@ yann.esposito@gmail.com
+ @yogsototh
+
yogsototh
+
yogsototh
+
yogsototh
+
yogsototh
ADA: DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
I am a Senior Software Engineer (Clojurist) for Cisco, Threatgrid team.
+I was a Machine Learning expert and Software Engineer for Vigiglobe.
+I tend to use functional programming a lot. Mostly Haskell and Clojure.
+I am generally passionate about:
+But before all, I love to learn. For example, I learned many programming languages:
+Functional:
+ +Object Oriented:
+ +Also:
+ + +
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ It is not exactly a CMS. But a Framework to generate static web pages.
+You have to program yourself webpages, the code to generate the menu…
+I added feature to make my website multilingual for example
+You’ll can find many informations on the official nanoc website.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ As Andy Lester told me ack is a simple file you only have to copy in your ~/bin folder. Now I’ve got ack on my professional server.
Go on http://betterthangrep.com to download it.
+Sincerely, I don’t understand ack don’t become a common command on all UNIX systems. I can no more live without. For me it is as essential as which or find.
One of the my main usage of grep is
Most of time it is enough. But it is far better with colored output. ack-grep in Ubuntu does that. As I couldn’t install it on my ‘Evil Company Server’, I had done one myself in very few lines:
#!/usr/bin/env zsh
+(($#<1)) && { print 'usage: ack "regexp"' >&2; exit 1 }
+
+listeFic=( **/*(.) )
+autoload zargs
+zargs -- $listeFic -- grep $1 | perl -ne 'use Term::ANSIColor;
+if (m/([^:]*)(:.*)('$1')(.*)/) {
+ print color("green").$1;
+ print color("reset").$2;
+ print color("black","on_yellow").$3;
+ print color("reset").$4."\n";
+} 'For my team and I it is usable enough. I hope it could help.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ 
+…this movie must be watched knowing you’ll cannot resolve the solution. At his best you’ll can suggest an interpretation close to the one of David Lynch.
I believe I had found a coherent interpretation which allow to follow the movie without being totally lost. I believed it can give the keys necessary to make its own idea of the movie…
Lost Higway is a really good movie. You keep watching it event it seem totally obscure. This is one of the strength of David Lynch.
+The first time I watched Lost Highway, I was a bit lost. Here some of explanations of Lost Highway I found on the Internet:
+and I don’t speak about many point of view found in forums.
+I finished to find two good site talking about this movie. But none of them still totally convinced me:
+Nonetheless, this movie must be watched knowing you’ll cannot resolve the solution. At his best you’ll can suggest an interpretation close to the one of David Lynch.
+I believe I had found a coherent interpretation which allow to follow the movie without being totally lost. I believed it can give the keys necessary to make its own idea of the movie.
+
+Like the protagonist, everybody see what he want to see in this movie. It is an invitation to think. Watch this movie is a little like watch a Rorschach’s test. What do we see in it? Everybody put its own personnality in the interpretation of the movie.
+Generally, we stay in this movie and we fail explaining everything. There is almost always a point that don’t fit within the interpretation of the movie. This is why trying to find a unique good interpretation of this movie is a mistake.
+I give an interpretation and not an explanation. Just to tell my vision of the movie should be very different from yours. There is certainly many coherent explanations.
+I write this post because I believe I had found an interpretation which seems coherent for most of the movie.
+All is in Fred’s memory
+In a first, it is clear for me, it is not a fantastic movie. If you follow this line, you’ll face many problem explaining some scenes.
+My hypothesis is the movie describe the Fred’s representation of reality. Each of his tries to escape reality will fail.
+Fred had commited an horrible act, a murder, and try to repair his memory to accepts it. He’ll then create alternative realities.
+Because of the dialog at the begining of the movie. Cops ask Fred if he’s own a video camera:
+++“Do you own a video camera?”
+
+“No, Fred hates them.”
+“I like to remember things my own way.”
+“What do you mean by that?”
+“How I remember them, not necessarily the way they happened.”
Then, what we see is not reality but the Fred’s perception. Fred is the God of the reality we see. This is why some God/Devil interpretation of the movie works not so bad.
+
+Who’s this mysterious man? He tells Fred it’s him who invited him in his house. He’s present at the party and in the house of Fred in the same time. Eyes wide open, looking everything Fred’s doing?
+It’s a key of the movie. In my humble opinion, I believe it represents the bad part of Fred. Certainly jalousy. If I was catholic, I’ll said he’s Satan. He observe, film but don’t act. He helps Fred to kill Dick Laurent. Fred had let him enter and cannot let him go. As Iago of Shakespeare is imprisonned by its own jalousy. The Mysterious Man help Fred doing the acts of violence. It also force Fred to remember the reality.
+When he makes love to his wife (Renee), he sees the face of the Mysterious Man instead of his wife’s face. In reality, it’s the same person for Fred. It should be her who’s the origin of his interior badness.
+Certainly it’s the mysterious man (Fred himself) who makes them. Their reason should be:
+There is many possibilities here. But we have many indices. Here is a supposition.
+The protagonist is a garagist fallen in love with a porno actress. He believe the producer is the bad guy who go again his will. Then he kills Dick Laurent.
+He was really married, he had killed his wife. The the remorse let him create an alternate self, which live in a kind of perfect world. But after the time pass, his obsession about the murder came again. And nobody could know if he had killed Andy or not.
+The second hypothesis seems better. We can make much more interpretation with it. It explain in most part the strange phone call from Dick Laurent to Pete. But the first hypothesis remain coherent. And, we should probably make an in depth explanantion using the first hypothesis. And I’m not sure it would be better.
+One of the strength of this movie is to understand there is many other coherent hypothesis. It is an expression of the Rashomon effect. Many different persons could describe in a coherent manner what they saw. But each description contradicts the others.
+There is much to tell about this movie. But I believe I put all essential keys here. It is a proof this movie is not a random one.
+I believe it is essential to remember the “test of Rorschach effet” when watching this movie.
+I’d like to know or opinion ; is my interpration wrong?
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ My wife bought about 500€ (at least) of TV Shows on iTunes. She bought the first season of Battlestar Gallactica in english (she notified the language after the dowload). DRM make it impossible to play it with french sub-titles.
++WTF? +
+Result, my wife would never buy any TV show on iTunes. She don’t like DVD because it is not as easy to buy and to use than to simply download episodes.
+Therefore far less money for you EVIL Copyrighter!!!!!
+My wife won’t see these episodes.
This is a ‘LOSE-LOSE’ cooperation.
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ I use git simply to synchronize stuff for personnal projects. Therefore, when I create a local branch I want most of time this branch to be created remotely.
+Here is the script I use to achieve that:
+#!/usr/bin/env zsh
+
+if (($#<1)); then
+ print -- "usage: $0:t branch_name" >&2
+ exit 1
+fi
+
+branch=$1
+git br ${branch}
+git co ${branch}
+git config branch.${branch}.remote origin
+git config branch.${branch}.merge refs/heads/${branch}Of course, I suppose origin is already configured.
Edit: Now I use git push -u
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ 
+I use Git to manage my personnal projects. I have a centralized repository which all my computer should synchronize with. Unfortunately I didn’t find clearly what I needed on the official Git documentation.
+In two words, if you want to use an SVN workflow with Git (and all its advantages) here is how to proceed.
+Suppose I’ve got a directory on my local computer containing a project I want to manage via Git. Here what to do:
+ +Now all files in the to/project/directory/ are versionned. If you want not to follow some just edit the file .gitignore
for example mine is:
+Next, you want to put your project on a directory accessible from the web:
+ +Now on any computer you can do:
+ +and local_directory will contain an up-to-date project.
You should make this operation also on the computer used to create the repository. Just to verify all will be okay.
+ +To resume you now have one repository on the Internet, and one or many computer associated with it. Now, what you want is to synchronize everything.
+Before begining your work, the first thing to do is to get all modification from the Internet to your local host:
+After that you can do (many times):
+ +When you want your local modification to be on the Internet just do a simple:
+All should be ok.
+If you have some trouble with the push and pull verify your .git/config file ; it should contain the following lines:
Well, now, all seems ok, but you have to worry about two little things. Git is all about decentralisation and branches. It is very easy to manage one branch, or many branches on the same host. But synchronize branches on many hosts is not a natural operation.
+This is why I created two simple scripts to automate this. One for creating a branch locally and remotely. And one to get remotely created branched on your local host.
+Then when you want to create a new branch (locally and remotely) ; you simply have to do a:
+git-create-new-branch branch_name
+and when you are on another computer and want to get locally all the remote branches you execute:
+git-get-remote-branches
+Here are the code of theese two scripts:
+#!/usr/bin/env zsh
+
+# recup branches not on local
+localbranches=( $(git br | sed 's/\*/ /') )
+remoteMissingBranches=( $(git br -r | \
+ egrep -v "origin/HEAD|(${(j:|:)localbranches})" ) )
+for br in $remoteMissingBranches; do
+ branch=${br#origin/}
+ print "get remote branch $branch"
+ git br ${branch}
+ git config branch.${branch}.remote origin
+ git config branch.${branch}.merge refs/heads/${branch}
+done
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ I upgraded to Mac OS X 10.6 Snow Leopard(c), and my YClock screensaver didn’t work on it. After searching on google, the problem seems to be just a recompilation away. Unfortunately, even recompiling it in 64 bit it didn’t work either. After a bit more research (thanks to ElectricSheep ).
+I discovered the good parameters for compilation.
+
+For now I didn’t compiled it to work also on Tiger and Leopard. I don’t know XCode enought to know how to make the Garbage collector to be disabled on 32 bits version and enabled on 64 bits version.
+It was a bit difficult to discover these informations. Hope this post helped someone.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ In order to bypass evil company firewall and to surf safely on unsafe
Then from my laptop or my local computer I just have to launch the marvelous
+ +and a local
I get this information from this post.
+Here I don’t want to talk about how great
I have Mac with Snow Leopard(c) at home and it is far from enough to modify the /etc/sshd.config file. The system use launchd to launch starting daemons.
I posted the question on Apple Discussions in this discussion thread. Thanks to all guys who helped me. And the solution is:
+Create the file /Library/LaunchDaemons/ssh-443.plist containing:
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+ <key>Disabled</key>
+ <false/>
+ <key>Label</key>
+ <string>local.sshd</string>
+ <key>Program</key>
+ <string>/usr/libexec/sshd-keygen-wrapper</string>
+ <key>ProgramArguments</key>
+ <array>
+ <string>/usr/sbin/sshd</string>
+ <string>-i</string>
+ </array>
+ <key>Sockets</key>
+ <dict>
+ <key>Listeners</key>
+ <dict>
+ <key>SockServiceName</key>
+ <string>https</string>
+ </dict>
+ </dict>
+ <key>inetdCompatibility</key>
+ <dict>
+ <key>Wait</key>
+ <false/>
+ </dict>
+ <key>StandardErrorPath</key>
+ <string>/dev/null</string>
+ <key>SHAuthorizationRight</key>
+ <string>system.preferences</string>
+</dict>
+</plist>It is a copy of /System/Library/LaunchDaemons/ssh.plist with some modifications:
SockServiceName from ssh to https.Label from com.openssh.sshd to something not existing as local.sshdTell me if it was helpfull or if you have any question.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ I changed from whos.amung.us to Google Analytics.
+Most of time I prefer not to use the same product as everybody and try some new. But this time I believe whosamung.us had too much ads on the page. I had to put their image on my website and they only give then number of user currently on the website, not the number of visits.
+This is why I now use google analytics. The only problem, remains for pages with no javascript support.
+Then for now:
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ iDisk should soon disapear. This entry is mainly obsolescent now.
+I updated my script which is now incremental. Since the writing of this article, Apple(c) had made many efforts about the bandwith of its European servers.
+I live in France and iDisk upload is just terrible. Upload speed remind me the old 56k modem. Most operations such as list the content of a directory take at least 30 seconds (for 15 elements). Renaming a directory fail most of time.
+Apple(c) use a WebDav server to host files. It works on port 80 (like http). I realized WebDav via https work better (2 to 3 times faster with far less errors). But even https is too slow.
+I upload from my Mac and sometimes from an Ubuntu PC (iDisk mounted with webdavfs).
+Here is the script I use in order to synchronize my website with maximum safety. It try each operations until it works.
+The idea are:
+For now I use rsync which in fact is no more efficient than a simple cp with WebDav. And I should use a method to keep track of elements who have changed. before the publication.
In fact when I’m on a Mac, I use Transmit which is very cool and far more efficient than the Finder to synchronize files. After the synchronization, I swap the directories.
+My script take a -s option in order to make only the swap option. It also take a -a in order to put the new index.html which should point to the new homepage (not the iWeb one).
In order to keep this script working for you, just modify the username by yours (the value of the mobileMeUser).
#!/usr/bin/env zsh
+
+# Script synchronisant le site sur me.com
+# normalement, le site est indisponible le moins de temps possible
+# le temps de deux renommages de répertoire
+
+mobileMeUser="yann.esposito"
+siteName="siteName"
+
+# Depending of my hostname the
+if [[ $(hostname) == 'ubuntu' ]]; then
+ iDisk='/mnt/iDisk'
+else
+ iDisk="/Volumes/$mobileMeUser"
+fi
+
+root=$HOME/Sites/$siteName
+destRep=$iDisk/Web/Sites/$siteName
+
+[[ ! -d $root ]] && {
+ print -- "$root n'existe pas ; vérifiez la conf" >&2;
+ exit 1
+}
+
+[[ ! -d $destRep ]] && {
+ print -- "$destRep n'existe pas, veuillez remonter le FS" >&2;
+ exit 1
+}
+
+if [[ $1 == '-h' ]]; then
+ print -- "usage: $0:h [-h|-a|-s]"
+ print -- " -a sychronise aussi l'index"
+ print -- " -h affiche l'aide"
+ print -- " -s swappe simplement les répertoires"
+fi
+
+if [[ $1 == '-a' ]]; then
+ print -- "Synchronisation de l'index (${destRep:h})"
+ rsync -av $root/index.html ${destRep:h}/index.html
+fi
+
+print -- "Root = $root"
+print -- "Dest = $destRep"
+
+if [[ ! $1 = '-s' ]]; then
+ [[ ! -d $destRep.tmp ]] && mkdir $destRep.tmp
+ print -P -- "%B[Sync => tmp]%b"
+ result=1
+ essai=1
+ while (( $result > 0 )); do
+ rsync -arv $root/Scratch/ $destRep.tmp
+ result=$?
+ if (( $result > 0 )); then
+ print -P -- "%BEchec du rsync%b (essai n°$essai)" >&2
+ fi
+ ((essai++))
+ done
+fi
+
+# SWAP
+print -P -- "%B[Swap des Répertoires (tmp <=> target)]%b"
+essai=1
+while [[ -e $destRep.old ]]; do
+ print -n -- "suppression de $destRep.old"
+ if ((essai>1)); then
+ print " (essai n°$essai)"
+ else
+ print
+ fi
+ ((essai++))
+ \rm -rf $destRep.old
+done
+
+print -- " renommage du repertoire sandard vers le .old"
+essai=1
+while [[ -e $destRep ]]; do
+ mv $destRep $destRep.old
+ (($?)) && print -- "Echec du renommage (essai n°$essai)" >&2
+ ((essai++))
+done
+
+print -- " renommage du repertoire tmp (nouveau) vers le standard"
+print -P -- " %BSite Indisponible%b $(date)"
+essai=1
+while [[ ! -e $destRep ]]; do
+ mv $destRep.tmp $destRep
+ (($?)) && print -P -- "%B[Site Indisponible]%b(essai n°$essai) Echec du renommage (mv $destRep.tmp $destRep)" >&2
+ ((essai++))
+done
+
+print -P -- "\t===\t%BSITE DISPONIBLE%b\t==="
+
+print -- " renommage du repertoire old vers le tmp"
+essai=1
+while [[ ! -e $destRep ]]; do
+ mv $destRep.old $destRep.tmp
+ (($?)) && print -P -- "Echec du renommage n°$essai" >&2
+ ((essai++))
+done
+
+print -P -- " publication terminée"#!/usr/bin/env zsh
+
+# Author: Yann Esposito
+# Mail: yann.esposito@gmail.com
+# Synchronize with "mobileMe" iDisk account.
+
+mobileMeUser="firstname.lastname"
+siteName="siteName"
+
+# Depending of my hostname the
+if [[ $(hostname) == 'ubuntu' ]]; then
+ iDisk='/mnt/iDisk'
+else
+ iDisk="/Volumes/$mobileMeUser"
+fi
+
+root=$HOME/Sites/$siteName
+destRep=$iDisk/Web/Sites/$siteName
+
+[[ ! -d $root ]] && {
+ print -- "$root does not exist ; please verify the configuration ($0)" >&2;
+ exit 1
+}
+
+[[ ! -d $destRep ]] && {
+ print -- "$destRep does not exist, please mount the filesystem" >&2;
+ exit 1
+}
+
+if [[ $1 == '-h' ]]; then
+ print -- "usage: $0:h [-h|-a|-s]"
+ print -- " -a sychronize primary index"
+ print -- " -h show this help"
+ print -- " -s only swap directories"
+fi
+
+if [[ $1 == '-a' ]]; then
+ print -- "Index synchronisation (${destRep:h})"
+ rsync -av $root/index.html ${destRep:h}/index.html
+fi
+
+print -- "Root = $root"
+print -- "Dest = $destRep"
+
+if [[ ! $1 = '-s' ]]; then
+ [[ ! -d $destRep.tmp ]] && mkdir $destRep.tmp
+ print -P -- "%B[Sync => tmp]%b"
+ result=1
+ essai=1
+ while (( $result > 0 )); do
+ rsync -arv $root/Scratch/ $destRep.tmp
+ result=$?
+ if (( $result > 0 )); then
+ print -P -- "%Brsync failed%b (try n°$essai)" >&2
+ fi
+ ((essai++))
+ done
+fi
+
+# SWAP
+print -P -- "%B[Directory Swap (tmp <=> target)]%b"
+essai=1
+while [[ -e $destRep.old ]]; do
+ print -n -- "remove $destRep.old"
+ if ((essai>1)); then
+ print " (try n°$essai)"
+ else
+ print
+ fi
+ ((essai++))
+ \rm -rf $destRep.old
+done
+
+print -- " renommage du repertoire sandard vers le .old"
+essai=1
+while [[ -e $destRep ]]; do
+ mv $destRep $destRep.old
+ (($?)) && print -- "Failed to rename (try n°$essai)" >&2
+ ((essai++))
+done
+
+print -- " renaming folder tmp (new) to the standard one"
+print -P -- " %BThe WebSite isn't working%b $(date)"
+essai=1
+while [[ ! -e $destRep ]]; do
+ mv $destRep.tmp $destRep
+ (($?)) && print -P -- "%B[WebSite not working]%b(try n°$essai) Failed to rename (mv $destRep.tmp $destRep)" >&2
+ ((essai++))
+done
+
+print -P -- "\t===\t%BWEBSITE SHOULD WORK NOW%b\t==="
+
+print -- " rename old folder to tmp folder"
+essai=1
+while [[ ! -e $destRep ]]; do
+ mv $destRep.old $destRep.tmp
+ (($?)) && print -P -- "Failed to rename n°$essai" >&2
+ ((essai++))
+done
+
+print -P -- " Publish terminated"
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ In fact this method works for old threads. But it fails to create new post threads. This is why I tried and be conquered by intensedebate, as you can see in the bottom of this page.
+Remark I didn’t have any comment on my blog when I switched. Therefore my lack of influence was a good thing :-).
+Before begining, I must state that I love Disqus.
+I know there is a similar blog entry at Trephine.org. Here I just add a straight and easy way to load disqus asynchronously using jQuery.
+I also know there is a jQuery plugin to make just that. Unfortunately I had some issue with CSS.
+Now let’s begin.
+Why should I want to load the disqus javascript asynchronously?
+I give a solution with jQuery, but I’m certain it will work with many other js library.
+replace:
+ +by
+If you forget the window.disqus_no_style=true; then your page will be blank. Simply because without this option, the javascript use a document.write action after the document was closed, which cause a complete erasing of it.
But with this option you still need to provide a CSS. This is why you have to copy the css code from the embed.js file and rewrite it in a CSS file. You can download the CSS I obtained.
Now it’s done. I believe all should be fine but I just finished the manip for my own site only 1 hour ago. Therefore there should be some error, tell me if it is the case.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ I made a blog entry about how I tried to integrate Disqus. I had to wait Disqus comment to be displayed before loading correctly my page. This is why I tried to include it in a “non-blocking” way. Unfortunately, I had difficulties to make it works correctly.
+Furthermore, it was not trivial to make comment to be shared between multiple version of the same page (each page has three differents representations, one for each language and one more for the multi-language version).
+I am a bit sad to quit Disqus because I must confess giannii had helped me has efficiently as he could. But the problem I had with disqus are inherent to some design choice not simply technical ones.
+During the time I tried to integrate Disqus I never tried Intense Debate. Now that I have tried, i must confess it does exactly what I needed.
+In order to make it fully asynchronous, you’ve just to download their common js and replace the following line:
+ +by:
+To conclude, main advantages (for me) of Intense Debate over Disqus:
+Voilà.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Here is how I done the tag cloud of my blog. It is done mostly in jQuery. All my site is static and pages are generated with nanoc. It is (in my humble opinion) the modern geek way to make a website. The tagcloud should work for machine with and without javascript.
+This is why I’ll give only a Ruby Generator, not a full javascript generator. But you can easily translate from Ruby to Javascript.
+Here is what you should obtain:
+<%= tagCloud %>
+Here is the simple jQuery code:
+This code will hide all the div containing links to articles containing the tag. And create a function do show the div containing the tag.
+For each tag I create a span element:
+and a div containing links associtated to this tag:
+Here is how I generate this using nanoc 2.
+If you want to make it fully jQuery one, it shouldn’t be too difficult, to use my ruby code and translate it into javascript.
+In a first time tags correpond of the list of all tags.
A function to create a data structure associating to each tag its occurence.
+I also need a data structure who associate to each tag a list of pages (at least url and title).
+Calculate the real size of each tag to be displayed.
+I choosen not to use the full range of size for all the tag. Because if no tag has more than n (here 10) occurences, then it doesn’t deserve to be of the maximal size.
def tagRealSize
+ tags=tagNumber
+ max=tags.values.max
+ min=tags.values.min
+ # size in CSS em.
+ minSize=1.0
+ maxSize=2.5
+ tagSize={}
+ tags.each do |t,n|
+ if ( max == min )
+ tagSize[t]=minSize
+ else
+ # normalized value between 0 and 1
+ # if not tag appear more than 10 times,
+ # then it cannot have the maximal size
+ tagSize[t]=[ ( n - min + 0.0 ) / ( max - min ) ,
+ (n - min) / 10.0 ].min
+ # from normalized size to real size
+ tagSize[t]=( tagSize[t] ) * (maxSize - minSize) + minSize
+ end
+ end
+ return tagSize
+endFinaly a function to generate the XHTML/jQuery code
+# generate an XHTML/jQuery code for tag cloud
+def tagCloud
+ tagLinks=tagRefs
+ tagSize=tagRealSize
+
+ # begin to write the code
+ tagCloud=%{<script type="text/javascript">
+ $(document).ready( function(){$('.list').hide();} );
+ function tagSelected(id) {
+ $('.list').hide();
+ $('#'+id).fadeIn();
+ $('.tag.selected').removeClass('selected');
+ $('#tag_'+id).addClass('selected');
+ }
+ </script><div id="tagcloud">}
+ # Creation of the tags <span>
+ tagSize.sort{|a,b| a[0].downcase <=> b[0].downcase}.each do |t,s|
+ tag_in_id=t.gsub(/\W/,'_')
+ # HTML protected version of the tag
+ # for example, replace ' ' by ' '
+ protected=t.gsub(/&/,'&').gsub(/ /,' ').gsub(/</,'<').gsub(/>/,'>')
+ tagCloud <<= %{
+ <span style="font-size: #{s}em;"
+ class="tag"
+ onClick="tagSelected('#{tag_in_id}')"
+ id="tag_#{tag_in_id}">
+ #{protected}
+ </span> }
+ end
+ tagCloud <<= %{</div><div id="hiddenDivs" >}
+ # Creation of the divs containing links associated to a tag.
+ tagLinks.each do |t,l|
+ tag_in_id=t.gsub(/\W/,'_')
+ tagCloud <<= %{
+ <div id="#{tag_in_id}" class="list">
+ <h4>#{t}</h4><ul>}
+ # generate the link list
+ l.each do |p|
+ tagCloud <<= %{<li><a href="#{p.path}">#{p.title}</a></li>}
+ end
+ tagCloud <<= %{</ul></div>}
+ end
+ tagCloud <<= %{</div>}
+ return tagCloud # yeah I know it is not necessary
+endYou can download the complete file to put in your ‘lib’ directory.
+Of course to be nice you need the associated CSS
+That’s all folks.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ My problem is simple:
+I want to filter a text except some part of it. I can match easily the part I don’t want to be filtered. For example
+ +I searched a better way to do that, but the best I can do is using split and scan.
def allExceptCode( f, content )
+ # Beware the behaviour will change if you add
+ # parenthesis (groups) to the regexp!
+ regexp=/<code[^>]*>.*?<\/code>|<pre[^>]*>.*?<\/pre>/m
+ tmp=""
+ mem=[]
+ content.scan(regexp).each do |c|
+ mem <<= c
+ end
+ i=0
+ content.split(regexp).each do |x|
+ tmp <<= send(f,x)
+ if not mem[i].nil?
+ tmp <<= mem[i]
+ i+=1
+ end
+ end
+ tmp
+endAn usage is:
+ +A better syntax would be:
+I would expect the split make a search on a regular expression and then give the matched expression into the $& variable. But it is not the case.
If someone know a nicer way to do that I will be happy to know how.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ I already talked about how I synchronized my website with mobileme. I ameliorated this script in order to make it incremental.
+Here is my new script, it first create a map which associate to each file its hash. After that it compare this file to the remote one. Then for each different file, update the content.
+Even with this script I also have some problem. Mostly due to ‘webdav’ issues. For example, renaming a folder work really badly (on Linux at least). I use webdavfs. For example:
+ mv folder folder2
+It returns OK and I’ve got:
+ $ ls folder folder2
+Booh….
+In order to handle most webdav issues I use a framework in zsh. It handle almost all except the correct renaming of folder. Working on it… Anyway here is the code I use.
+ #!/usr/bin/env zsh
function samelineprint { print -n -P – "\r$*" }
+maxessais=300
+function trymkdir { target=“$1” print – mkdir -p $target local essai=1 while ! mkdir -p $target; do samelineprint "Echec: essai n°$essai" ((essai++)) ((essai>maxessais)) && exit 5 done print }
+function trycp { element=“$1” target=“$2” if [[ ! -d ${target:h} ]]; then trymkdir ${target:h} fi local essai=1 print – cp $element $target while ! $element $target; do samelineprint "Echec: essai n°$essai" ((essai++)) ((essai>maxessais)) && exit 5 done print }
+function tryrm { target=“$1” local essai=1 local options=’’ [[ -d $target ]] && options=‘-rf’ print – rm $options $target while ! rm $options $target; do samelineprint "Echec: essai n°$essai" ((essai++)) ((essai>maxessais)) && exit 5 done essai=1 while [[ -e $element ]]; do samelineprint “rm reussi mais fichier source non disparu n°$essai” sleep 1 ((essai++)) ((essai>maxessais)) && exit 5 done print }
+function tryrename { element=“$1” target=“$2” local essai=1 while [[ -e $target ]]; do samelineprint “Echec n°$essai le fichier $target existe déjà” ((essai++)) ((essai>maxessais)) && exit 5 sleep 1 done print – mv $element $target while ! mv $element $target; do samelineprint "Echec: essai n°$essai" ((essai++)) ((essai>maxessais)) && exit 4 done essai=1 while [[ -e $element ]]; do samelineprint “mv reussi mais fichier source non disparu n°$essai” sleep 1 ((essai++)) ((essai>maxessais)) && exit 5 done print }
+And here is the code on how I synchronize my website. There is a little cryptic code. It correspond a problem caused by the bluecloth filter which is a markdown program made in ruby. Each time my email is written it is transformed differently. This is why I remove this part from the content of each html file. Without it, all my files containing email are different at each regeneration of my website.
+ #!/usr/bin/env zsh
source $0:h/config
+source $0:h/webdav-framework
+if [[ $1 == ‘-h’ ]]; then print – “usage : $0:h [-h|-s|-d]” print – " -a sychronise aussi l’index" print – " -h affiche l’aide" print – " -d modification directe (pas de swap)" print – " -s swappe simplement les répertoires" fi
+function incrementalPublish { local ydestRep=destRepsuffix localRef=“$srcRep/map.yrf” print – “Creation du fichier de references” create-reference-file.sh > $localRef remoteRef="/tmp/remoteSiteMapRef.$$.yrf" if [[ ! -e "$ydestRep/map.yrf" ]]; then # pas de fichier de reference sur la cible print – “pas de fichier de reference sur la cible, passage en mode rsync” rsyncPublish swap else trycp “$ydestRep/map.yrf" "$remoteRef” typeset -U filesToUpdate filesToUpdate=( $(diff $localRef $remoteRef | awk ’/1/ {print $2}' ) ) if ((${#filesToUpdate} == 1)); then print – “Seul le fichier ${filesToUpdate} sera téléversé" elif ((${#filesToUpdate}<10)); then print –”${#filesToUpdate} fichiers seront téléversés :" print -- "${filesToUpdate}" else print – “${#filesToUpdate} fichiers seront téléversés” fi # copy all file with some differences # except the map in case of error for element in $filesToUpdate; do if [[ $element == “/map.yrf” ]]; then continue fi if [[ -e srcRepelement ]]; then trycp srcRepelement ydestRepelement else tryrm ydestRepelement fi done # if all went fine, copy the map file trycp $srcRep/map.yrf $ydestRep/map.yrf # remove the temporary file }
+function rsyncPublish { result=1 essai=1 while (( $result > 0 )); do print – rsync -arv $srcRep/ $destRep.tmp if ((!testmode)); then rsync -arv $srcRep/ destRep.tmpfiresult=? if (( $result > 0 )); then print -P -- "%BEchec du rsync%b (essai n°$essai)" >&2 fi ((essai++)) done }
+function swap { print -P – “%B[Directory Swap (tmp <=> target)]%b” [[ -e $destRep.old ]] && tryrm $destRep.old
+print -- " renommage du repertoire sandard vers le .old"
+tryrename $destRep $destRep.old
+
+print -- " renommage du repertoire tmp (nouveau) vers le standard"
+print -P -- "%B[Site Indisponible]%b $(date)"
+tryrename $destRep.tmp $destRep
+print -P -- "%B[Site Disponible]%b $(date)"
+
+print -- " renommage du repertoire old vers le tmp"
+tryrename $destRep.old $destRep.tmp
+
+print -P -- " publication terminée"}
+print – “Root = $webroot” print – “Dest = $destRep”
+if [[ “$1” = “-s” ]]; then swap else if [[ “$1” = “-d” ]]; then suffix="" else suffix=“.tmp” fi print -P – “%BSync%b[${Root:t} => destRep : tsuffix]” incrementalPublish fi +This is my way to replace rsync with filesystem not handling it. Hope it is usefull. I’ll be happy to hear a way to handle the webdav rename folder problem. This is really annoying.
<>↩
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Avec Firefox et Safari cette page est bien plus jolie !This page is far nicer with Firefox and Safari!
.For developer IE is a nightmare. This is why, I use a method to disable my standard CSS and enable a IE only CSS. I use jQuery to accomplish that.
+$(document).ready( function() {
+ if ($.browser["msie"]) {
+ // include the ie.js file
+ $('head').append('<script type="text/javascript" src="/js/ie.js"></scr' + 'ipt>');
+ }
+});// Remove all CSS I don't want to use on IE
+$('link[rel=stylesheet]').each(function(i)
+{
+ if (this.getAttribute('href') == '/css/layout.css')
+ this.disabled = true;
+ if (this.getAttribute('href') == '/css/shadows.css')
+ this.disabled = true;
+ if (this.getAttribute('href') == '/css/gen.css')
+ this.disabled = true;
+}) ;
+
+// Append the CSS for IE only
+$('head').append('<link rel="stylesheet" type="text/css" href="/css/ie.css"/>');
+
+// I also add a message on top of the page
+$('body').prepend('<div id="iemessage"><p><span class="fr"><em>Avec <a href="http://www.firefox.com"> Firefox </a> et <a href="http://www.apple.com/safari">Safari</a> cette page est bien plus jolie !</em></span><span class="en"><em>This page is far nicer with <a href="http://www.firefox.com"> Firefox </a> and <a href="http://www.apple.com/safari">Safari</a>!</em></span></p>.</div>');That’s it.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ I believe the goal researched by minimalism is Focus. But I don’t believe minimalism should be the goal. Focus should be the goal, and I believe minimalism isn’t necessary to reach it.
+This is why my design is not minimalist, but I decided to remove most of the navigation stuff of all pages of my website. May be I’ll prefer to hide the menu only when you are on blog article. For now, I hide the menu everywhere on the website.
+For those who want the technical details behind the show/hide menu, here is the simple jQuery code.
+The HTML:
+ +The CSS:
+#menuButton {
+ font-size: 2em;
+ height: 2em;
+ line-height: 1.8em;
+ width: 2em;
+ position: fixed;
+ left: 0;
+ top: 0;
+ z-index: 9001 }
+
+#menuButton:hover {
+ cursor: pointer; }
+
+#entete {
+ top: 5em;
+ left: 0;
+ position: fixed;
+ width: 10em;
+ z-index: 9000; }The javascript code (using jQuery)
+function hideMenu() {
+ $('#entete').animate({left:"-10em"}, 500 );
+ $('#menuButton').html('→');
+}
+function showMenu() {
+ $('#entete').animate({left:"0em"}, 500 );
+ $('#menuButton').html('←');
+}
+function toggleMenu() {
+ if ( $('#entete').css('left')=='-10em' ) {
+ showMenu();
+ } else {
+ hideMenu();
+ }
+}And the result is shown in the top left corner of this website.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Here is a live example of what appear while loading my pages.
+ ++Hello! I’ve finished loading! +
++Click me to see me disapear again. +
+Loading… 
I first tried to integrate queryLoader, but it didn’t fill my needs.
+The plugin add a black div to hide all the content. But as the script had to be launched at the end of the source code my website show for a small time.
+In order to hide this small artefact, here is how I do that.
+In a first time, I added at the top of the body the div hiding all the content.
+ +and here is the associated CSS to #blackpage:
and the associated jQuery code:
+ +Yes, it is as simple as that. And, putting the #blackpage div at the top of my page, I ensure to hide anything while loading.
I hope it had helped you!
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ I discussed earlier why I prefer to hide my navigation menu. I finally decided to hide it only after a short time. Just the time needed for a user to see it. But how make it disappear only when it is not used for some time?
+Here is how to accomplish that easily.
+HTML:
+ <div id="menuButton"></div>
+ <div id="entete">
+ <ul>
+ <li> menu item 1 </li>
+ ...
+ <li> menu item n </li>
+ </ul>
+ </div>CSS:
+ #entete {
+ top: 1em;
+ left: 0;
+ position: fixed;
+ width: 10em;
+ z-index: 2000; }
+
+ #entete {
+ top: 1em;
+ height: 22em;
+ left: 0;
+ position: fixed;
+ width: 10em; }Javascript:
+var last=0;
+
+// will hide the menu in 5 seconds
+// if the variable 'last' has not changed its value
+function autoHideMenu(value) {
+ setTimeout(function(){
+ if ( last == value ) { hideMenu(); }
+ },5000);
+}
+
+$(document).ready( function() {
+ // show the menu when the mouse is on
+ // the good area
+ $('#menuButton').hover(showMenu);
+
+ // If the mouse is on the menu change the
+ // value of 'last'
+ // try to hide the menu when the mouse
+ // go out off the menu.
+ $('#entete').hover(
+ function(){last+=1;},
+ function(){autoHideMenu(last);} );
+ autoHideMenu(0);
+});
+
+// show / hide menu functions details
+
+// move to the left
+function hideMenu() {
+ $('#entete').animate({left:"-10em"}, 500 );
+}
+
+// move to right and will try to hide in 5 sec.
+function showMenu() {
+ $('#entete').animate({left:"0em"}, 500 );
+ last+=1;
+ autoHideMenu(last);
+}Simple and lightweight. No timer (almost), no memory leak, no Date…
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Here is a tip, I don’t know why, but I almost always forgot how to do that.
+When you want to launch a command and this command should not be killed after you close your terminal. Here is how to accomplish that from command line:
+ +where cmd is your command.
I let this command here for me and I wish it could also help someone.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ I explain why I had so much difficulties to use Git. There is an “untaught rule” that make hard to work without. Until I read the good document.
+“Cheap branches” aren’t designed to be totally isolated branches but rather should follow a “Master Branch”. There is a Standard Workflow to follow. If you don’t follow it, you prepare yourself with some hard time with Git.
+I was a huge user of subversion (svn). Until the day I saw this video of Linus Torvald. Where he explain Git and all advantages of Decentralized Concurrent Versioning System(DCVS)
+I must say I was completely convinced. And the more you learn about DCVS the more you see good reason to use them.
+I then needed a versioning system for my team. As they were not used to open source versioning system except those heavy, with a GUI and with and administrator†
+After some web searches, I founded three main choices:
+ +After trying each other I chosen Bazaar. It has the simplest User Interface*. My choice was done.
+It was really natural to learn when coming from subversion. The pull command corresponding to update, push command to commit. Commands like commit and update are still there if you want to use an SVN workflow.
After some times, reading on many blogs, I realize Git is far more popular and by influent people.
+I then decide to use Git in particular to version this current website. But after trying it, I found it difficult and couter intuitive (I’ll speak a work about it later).
+After calling for some help, when I say Bazaar is much simpler to learn, some people answer me that Git:
+++— SO-MUCH-EASY my 12 year old daughter uses it to version its school documents. She has no difficulties at all, creating branches, blah, blah, blah…
+
If a 12 years old girl has no problem with Git and I (with my Computer Science Ph.D.) have difficulties to uses it like I want, it is frustrating and humiliating. But what makes Git natural for some people and confusing for me?
+I finally understood why reading a document I didn’t read before. It was the untaught part of the conception. The part every developer found so natural it is not necessary to say a word about it. But it was not natural for me.
+† - I speak about ClearCase(c). I know there exists command line tools. But it was not the way my team used it.
+* - I never really given its chance to Mercurial. The terminology they chosen was too far from the svn one. And I was used to it.
+When you see explanation about branches and DCVS we imagine each branch is totally uncorrelated to each other, except when merging. Everything is magic. This is the “Parallel World” explanation. This way of seeing is explained more in depth in the real good article about branches on betterexplained.
+Git was designed to manage the Linux Kernel. Git was designed using the concept of Patch instead of Parallel Worlds.
+From one site Parallel World and Patches from the other. There is many equivalent notions in the two point of vue, but also some differences.
+I will not argument about which is the best. Just tell my vision of DCVS come from the Parallel World vision and Git was designed the other way‡.
+I believe I understood conceptual mechanism under Git. But I had some difficulties with real usage. The worst point, the one I didn’t get before long was because I didn’t get really well the notion of Cheap Branching.
+What is a Cheap Branch? If like me you come from Bazaar, it is a totally new notion. It is in fact the ability to create a branches all of them using the same directory.
+You just have to launch a Git command and the local directory reflect the state of the branch you selected.
+In theory, Cheap Branches are exactly like Bazaar branches. The word used is Branch and not Cheap Branch. But there is a slight difference between them. A slight difference between a Cloned Branch and a Cheap Branch.
+A “Standard branch” is what is theoretically a kind of new Parallel World. But Cheap branch was designed to be future Patch for the main branch of the directory/Cloned branch.
+Of course, I know anybody can state you can totally use Cheap branches as Cloned branches. But they weren’t designed for that. On daily usage, it is a bit uneasy to use it like this.
+Here how Git cheap branches should be used (for more details see Git for Designers):
+Here’s how you should not use Git:
+This simple minor difference of point of view confused me a lot.
+Now I have understood all that. I understand why Git has some many people claiming it is the best DCVS.
+Cheap branching notion is essential in Git and is a really useful feature. Particularly for this website. But, there are not exactly, completely parallel line of development. Because they are designed to path the main branch. Of course, it is not an obligation, but there are slight messages which tell you this should be used like that.
+If I want to separate in a better way some branches I just have to Clone them. And I return exactly in branches Bazaar provided me.
+For now, I prefer (from far) Bazaar terminology. They are cleaner and more understandable.
+bzr revert
+Is clearer than
+git reset –hard HEAD
+We can tell the same thing about
+bzr revert -r -3
+which seems preferable to
+git reset –hard HEAD~3
+Until now, it is not big business. But now, things will go worse. If we want to revert time on all the tree we use the keyword reset.
Now, if I want to revert time on on file. We should naturally imagine the command will be:
+git reset –hard FILE
+The solution is:
+git checkout FILE
+What? checkout !? Well, ok. I accept. why not? With Bazaar it is:
git revert FILE
+What I personally found far more natural.
+But the command to change the current cheap branch is really hard to be accepted (from the User Interface point of view). With Bazaar it is:
+cd ../branch
+Well yes. With Bazaar you have to change your directory to change your branch. It needs more disk resources but it is really clear. Which is my current branch, is just a pwd away. For Git here is the command:
git checkout branch
+WTF? I believed checkout was the key to get a file in some state (not the entire tree).
Then checkout is the same keyword used to get back in time on a file (BUT NOT ON ALL THE TREE where you have to use reset --hard) and to change current branch!
It is totally unnatural. Even if it is theoretically totally justified like you can see in the really good article Git for Computer Scientist. From the user point of vue, it is difficult to do worse than that. It is like somebody made it on purpose to make it the hardest possible to learn and understand.
++++
+- — Try to find the good keyword for this operation
+- — Wrong! Try again!
+- — False, it is not yet right!
+
That were the Git bad side. But It has many advantages. Once you’ve understood the cheap branching paradigm. All became clearer for me after. Even if there is also some difficulties with the edit of the .git/config files (not user friendly at all).
‡ I must precise that I worked a lot with multi-modal logic and particularly about “Temporal Logics” (linear or not). This is why I was more inclined to see things this way. “Ah ! Just to remember my firsts love with computer science !”
+Was it a good idea to change to a decentralised versionning system? Clearly yes. Decentralisation give far much great possibilities. Such as working on a fix on a totally isolated branches.
+Speaking about features I’ll tell Git is the best. But Git was too much in my way. Is was exactly what I didn’t want for my first DCVS.
+I shouldn’t have had those difficulties about understanding cheap branching which must be a patch. In reality, Git make a difference between the Tree and the Branch. Which is obviously not the case for Bazaar. Conceptually, bazaar is simpler to understand.
+In conclusion, I use Git more often than Bazaar and I must say, that I have some preferences for Git. However, Git lack hardly clear commands name like revert. For now I don’t made alias to correct that. But may be one day I should do that.
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ A detailed tutorial of Git for people knowing very few about versions systems. You’ll understand utility of such program and how we use modern version control system. I try to stay as pragmatic as possible.
+Here is the list of sufficient and necessary command to use Git. There is very few. It is normal not to understand immediately but it is to gives you an idea. Even if this article is long, 95% of Git usage is in these 7 commands:
+Get a project from the web:
+ +Everyday Git usage:
+# get modifications from other
+git pull
+# read what was done
+git log
+
+# Make local changes to files
+hack, hack, hack...
+# list the modified files
+git status
+# show what I've done
+git diff
+
+# tell git to version a new file
+git add new/file
+
+# commit its own modifications
+# to its local branch
+git commit -a -m "Fix bug #321"
+
+# send local modifications to other
+git pushThis article is written for people knowing very few about versionning systems. It is also written for those who had didn’t followed progress since CVS or subversion (SVN). This is why, in a first time I’ll explain quickly which are the goal of such systems. Secondly, I’ll explain how to install and configure Git. Then, I give the command for each feature a DCVS must have.
+If you just want to use Git immediately, just read dark part. You read this part later to understand correctly foundations of version systems and not doing strange things.
+Git is a DCVS, which means a Decentralized Concurrent Versions System. Let’s analyze each part of this long term:
+Firstly, versions system manage files. When somebody work with files without a versions system, the following happens frequently:
+When you modify a somehow critical file you don’t want to loose. You copy naturally this file with another name. For example:
+ +In consequence of what, the new file, play the role of backup. If you break everything, you can always return in the last state by overwriting your modifications. Of course, this method is not very professional and is a bit limited. If you make many modifications, you’ll end with many files with strange names like:
+If you want to make it works correctly, you’ll have to use naming convention. Files take many place even if you modify most of time only some lines.
+Fortunately, versions system are here to help.
+You only have to signal you want a new version of a file and the versions system will do the job for you. It will record the backup where it could be easily recovered. Generally, systems version do it better than you, making the backup only of the modified lines and not the total file.
+Once upon a time versions were managed for each file separately. I think about CVS. Then it naturally appears projects are a coherent set of files. Recover each file separately was a tedious work. This is why versions number passed from files to the entire project.
+It is therefore possible to say, “I want to get back three days earlier”.
+What gives versions system? (I didn’t mention everything at all)
+Version Systems are already useful to manage its own projects. They help to organize and resolve partially backup problems. I say partially because you have to backup your repository on a decent file system. But versions system are really interesting is on projects done by many people.
+Let’s begin by an example, a two person project ; Alex and Beatrice. On a file containing a Lovecraft’s gods list:
+ +Say Alex is home and modify the file: +
+Cthulhu
+Shubniggurath
+Soggoth
+Yogsototh
+
+after that he send the file on the project server. Then on the server there is the Alex file:
+A bit later, Beatrice who had not get the Alex file on the server make the modification:
+
+Cthulhu
+Dagon
+Shubniggurath
+Yogsototh
+
+Beatrice send her file on the server
+Alex modification is lost. One more time, versions system are here to help.
+A version system would had merge the two files at the time Beatrice send the file on the server. And like by magic, on the server the file would be:
++Cthulhu +Dagon +Shubniggurath +Soggoth +Yogsototh ++
In real life, at the moment Beatrice want to send her modifications, the versions system alert her a modification had occurred on the server. Then she uses a command which pull the modification from the server to her local computer. And this command update her file. After that, Beatrice send again the new file on the server.
+In what Concurrent Versions System help?
+This word became popular only recently about CVS. And it mainly means two things:
+First, until really recently (SVN), you’ll have to be connected to the distant server to get informations about a project. Like get the history. New decentralized systems work with a local REPOSITORY (directory containing backups and many informations linked to the versions system functionalities). Hence, one can view the history of a project without the need of being connected.
+All instances of a project can live independently.
+To be more precise, DCVS are base on the branch notion.
+Practically, it has great importance. It means, everybody work separately, and the system help to glue all their work.
+It is even more than just that. It help to code independently each feature and bug fixes. Under other system it was far more difficult.
+Typical example:
+++I develop my project. I’m ameliorating something. An urgent bug is reported.
+With a DCVS I can easily, get back to the version with the bug. Fix it. Send the fix. Get back to my feature work. And even, use the fix for the new version with my new feature.
+In a not decentralized version system, doing such a thing is possible but not natural. Decentralization means it become natural to use a branch for each separable work.
+
Advantages given by DCVS:
+Let’s resume what we can easily do with DCVS:
+Versions Systems
+Concurrent
+Decentralized
+Now let’s see how to obtain all these things easily with Git.
+Under Linux Ubuntu or Debian:
+ +Under Mac OS X:
+ + +Save the following file as your ~/.gitconfig.
[color]
+ branch = auto
+ diff = auto
+ status = auto
+[alias]
+ st = status
+ co = checkout
+ br = branch
+ lg = log --pretty=oneline --graph
+ logfull = log --pretty=fuller --graph --stat -p
+ unstage = reset HEAD
+ # there should be an article on what this command do
+ uncommit = !zsh -c '"if (($0)); then nb=$(( $0 - 1 )); else nb=0; fi; i=0; while ((i<=nb)); do git revert -n --no-edit HEAD~$i; ((i++)); done; git commit -m \"revert to $0 version(s) back\""'
+ undomerge = reset --hard ORIG_HEAD
+ conflict = !gitk --left-right HEAD...MERGE_HEAD
+ # under Mac OS X, you should use gitx instead
+ # conflict = !gitx --left-right HEAD...MERGE_HEAD
+[branch]
+ autosetupmerge = trueYou can achieve the same result using for each entry the command: git config --global. Next, configure your name and your email. For example, if your name is John Doe and your email is john.doe@email.com. Launch the following commands:
Here it is. Base configuration is over. The file containing alias will help to type shorter commands.
+If a project is already versionned with Git you should have an URL of the sources. Then use the following command:
If there is no git server but you’ve got an ssh access. Just replace the git://host by ssh://user@host. In order not to type your password each time, use:
Reply to question and do not enter a password. Then copy your keys to the distant server. This is not the safest way to do this. The safest being, using ssh-agent.
The easiest way if you have ssh-copy-id:
or manually
+me@locahost$ scp ~/.ssh/id_rsa.pub me@main.server:
+me@locahost$ ssh me@main.server
+password:
+me@main.server$ cat id_rsa.pub >> ~/.ssh/authorized_keys
+me@main.server$ rm id_rsa.pub
+me@main.server$ logoutNow you don’t need to write your password to access the main.server.
Suppose you already have a project with files. Then it is really easy to version it.
+ +Let do a small remark. If you don’t want to version every file. Typically intermediate compilation file, swap files… Then you need to exclude them. Just before launching the git add . command. You need to create a .gitignore file in the root directory of your project. This file will contain all exclude pattern. For example:
Now, if you want to create a repository on a distant server, it must not be in bare mode. The repository will contain only versionning informations, but not the files of the project. To achieve that:
Others will be able to get your modifications.
+ +You now have a local directory on your computer. It is versionned and you can say it is, because there is a .git directory at the root (and the root only) of your project. This directory contain all necessary informations for Git to version your project.
Now you only need to know how to use it.
+Here is one from many way to use Git. This method is sufficient to work on a project. Not there is many other workflows.
+Work with Git immediately:
+git pull,git log,git status and git diff,git add [file],git commit -a -m "message",git push (redo a git pull if push return an error).With these few commands you can use Git. Even if it is sufficient, you need to know one more thing before really begin ; How to manage conflicts.
+Conflicts can arise when you change the same line of code on the same file from another branch you’re merging. It can seems a bit intimidating, but with Git this kind of thing is really simple to handle.
+You start from the following file
+and you modify one line
+
+Zoot the pure
+
+except during this time, another user had also modified the same line and had done a push.
+Zoot, just Zoot
+
+Now when you do a:
+$ git pull
+remote: Counting objects: 5, done.
+remote: Total 3 (delta 0), reused 0 (delta 0)
+Unpacking objects: 100% (3/3), done.
+From /home/yogsototh/tmp/conflictTest
+ d3ea395..2dc7ffb master -> origin/master
+Auto-merging foo
+CONFLICT (content): Merge conflict in foo
+Automatic merge failed; fix conflicts and then commit the result.Our file foo now contains:
+<<<<<<< HEAD:foo +Zoot the pure +======= +Zoot, just Zoot +>>>>>>> 2dc7ffb0f186a407a1814d1a62684342cd54e7d6:foo ++
To resolve the conflict you only have to edit the file for example, writing:
+
+Zoot the not so pure
+
+and to commit
+ +Now you’re ready to use Git. Git provide many other functionnalities. Now we’ll see some Git usages older CVS couldn’t handle.
+Because with Git you can work on many part of some project totally independently. This is the true efficiency of decentralisation.
+Each branch use the same directory. Then you can easily change your branch. You can also change branch when some files are modified. You can then dispatch your work on many different branches and merge them on one master branch at will.
+Using the git rebase you can decide which modifications should be forget or merged into only one modification.
What does it mean for real usage? You can focus on coding. For example, you can code, a fix for bug b01 and for bug b02 and code a feature f03. Once finished you can create a branch by bug and by feature. And finally you can merge these modifications on a main branch.
+All was done to code and decide how to organize your versions after. In other VCS it is not as natural as in Git.
+With Git you can depend of many different sources. Then, there is not necessarily a ‘master’ repository where everybody puts its modifications.
+What changes the most with Git when you come from SVN, it’s the idea of a centralized project on one server. With Git many people could work on the same project but not necessarily on the same repository as main reference. One can easily fix a bug and send a patch to many different versions of a project.
+In the first part, we saw the list of resolved problem by Git. To resume Git should do:
+or more generally
+ +revert three version before (see my .gitconfig file).
Undo the las merge (if something goes wrong)
+ +list files being modified
+ +differences between last version files and local files
+ +differences between some version and local files
+ +To create a branch:
+ +To change the current branch:
+ +
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ It is unbelievable you cannot filter your call with an iPhone! The only reason I see for that is a negotiation with phone operator to force users to get phone advertising. It is simple unacceptable.
+I’m a λ iPhone’s user. The only way to filter your call and to manage blacklist is to jailbreak your iPhone. And I don’t want to do that. Then, if like me you find it unacceptable, just write a line to Apple: http://www.apple.com/feedback/iphone.html
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Why even if I believe git has many bad point I believe it is the best DCVS around to work with. This is why I first tell why I prefer Bazaar over Git. Secondly I’ll talk about the only advantage of git against Bazaar which lead me to prefer it.
Before beginning this article, you should know I come from subversion. I find subversion to be a really good CVS. But I was converted to the decentralized ones.
+There is two way of perceive version control system. Either you think in term of branches (see the really good article on betterexplained) or think in term of patches. Another way to say that, is weather you concentrate on vertices or on transitions of the graph of possible states of your project.
+This is the second approach who was behind git and this is the first behind Bazaar. git was created by Linus Torvald in order to close some gap in the version system used to develop the Linux kernel. And patches is a term which is more present than ‘state’ in the development community.
I first was convinced by Bazaar. Why? Argument in favor of Bazaar were: user friendly, terminology close to the subversion one. And I tried a bit the two, and it was clearly more natural for me to use Bazaar. But after seeing so many people using git I decided to give it a serious try.
And it was so fastidious! The git terminology was horrible! And it is nothing to say it.
gitThe first example, checkout is used to make only one thing from the technical point of vue. But from the user perspective, you make many different things with this word. Example:
undo the current modification of the file pipo
change the current branch to the branch pipo
And, like me, you remark, it is exactly the same command to make two completely different things. What occur when you have a pipo branch and a pipo file? By default, it change the current branch. In order to leave the ambiguity you have to use the following syntax:
Yes, hum…
+It works, but it is clearly not really user friendly. Furthermore, checkout had a complete different signification in older CSV like cvs et svn. checkout was used to get a distant project locally.
Bazaar terminology is far more natural, because there is no command to change the current branch as there is only one branch per directory. Changing a branch in Bazaar is changing the current directory. I also believe it is the biggest problem of Bazaar, I’ll tell you why. And to undo things in Bazaar:
+ +Furthermore, most Bazaar command take a revision number in parameter. For example, to get back 3 versions earlier, it is enough to write:
+ +The git equivalent is far more cryptic:
One more time, Bazaar is far more readable.
+Back in time for all the project:
+with Bazaar:
+ +and with git? git checkout? Of course not! It would be too simple. What we find in the documentation (man) and everywhere on the net:
Except that this command is horrible. It forget revisions! Then you must use it with prudence. And you cannot tell other people working on the project you discard some changes. If someone had pulled the bad version, you are doomed. This is why you can also use:
+ +Just to keep a backup branch. Without it we can definitively loose the current version HEAD. But some error may rest when there were some addition and deletion of files. The unique way to be really clean without any risk is to use the following command:
+for i in $(seq 0 2); do
+ git revert -n --no-edit head~$i;
+done
+git commit -m "reverted 3 versions back"And with this command this is the only good way to undo things in a project and tell other contributor you reverted something. You simply revert version in backward order.
+The rule is simple: NEVER use the git reset command on a version somebody else could have fetched
It was said. Discover the best method took me some time. I’d made many different tries. The safer and best way of reverting back your tree is to use this method. If you want to make it automatic just had the following alias in your ~/.gitconfig. Of course this alias will work only on environment having zsh installed. Which is the cas for most UNIX (Ubuntu, Mac OS X…).
[alias]
+ uncommit = !zsh -c '"if (($0)); then nb=$(( $0 - 1 )); else nb=0; fi; i=0; while ((i<=nb)); do git revert -n --no-edit HEAD~$i; ((i++)); done; git commit -m \"revert to $0 version(s) back\""'git by far the best DCVS todayAfter talking about the negatives points of git, now it’s time to speak about the very positive feature that make git the best DCVS in my humble opinion.
You always work into the same main directory. For example, you can work on two fix in the same time. Say fix1 require you to work on file1 and fix2 to work on file2. You can work in any order on file1 and file2 in the master branch. And then go to branch fix1, commit file1 into it. Then go to branch fix2 and commit file2 into it. And finally merge the two branches fix1 and fix2 into master.
> vim file1
+> vim file2
+> git br fix1
+> git add file1
+> git commit -m 'fix1'
+> git br fix2
+> git add file2
+> git commit -m 'fix2'
+> git commit master
+> git merge fix1
+> git merge fix2And this is great not to worry about working in the good branch and coding in the same time. You just worry about your code and then about the versionning system.
+And I use this possibilities a lot. Working with bazaar, I often made the error to begin a change in the bad branch. then I have to copy my modifications, then revert. In short it was tiedous.
+This is why I prefer using git on an every day usage. If Bazaar implement the same way of cheap branching than git. I should switch again.
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ I just found a way to change the default shell on Mac OS X. This note is mostly for me, but somebody else should find it useful. Just launch the following command:
+ > chsh
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ How to stop using bad Microsoft© font under Ubuntu Linux in order to user nice anti aliased font under Firefox.
+Just modify the /etc/fonts/local.conf with the following code:
+<?xml version="1.0"?>
+<!DOCTYPE fontconfig SYSTEM "fonts.dtd">
+<fontconfig>
+
+<!-- Miscellaneous settings -->
+
+<include ignore_missing="yes">misc.conf</include>
+
+<!-- Define alias -->
+
+<include ignore_missing="yes">alias.conf</include>
+
+<!-- Rules for Microsoft fonts -->
+
+<include ignore_missing="yes">msfonts-rules.conf</include>
+
+ <match target="pattern" name="family" >
+ <test name="family" qual="any" >
+ <string>Tahoma</string>
+ </test>
+ <edit mode="assign" name="family" >
+ <string>Verdana</string>
+ </edit>
+ </match>
+ <selectfont>
+ <acceptfont>
+ <pattern>
+ <patelt name="family">
+ <string>Lucida Grande</string>
+ </patelt>
+ </pattern>
+ </acceptfont>
+ </selectfont>
+
+ <match target="pattern" name="family" >
+ <test name="family" qual="any" >
+ <string>Georgia</string>
+ </test>
+ <edit mode="assign" name="family" >
+ <string>Georgia</string>
+ </edit>
+ </match>
+ <selectfont>
+ <acceptfont>
+ <pattern>
+ <patelt name="family">
+ <string>Century Schoolbook L</string>
+ </patelt>
+ </pattern>
+ </acceptfont>
+ </selectfont>
+
+</fontconfig>Hope it helped someone who like me had his eyes crying in face of such ugly fonts.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Sometimes you cannot simply write:
+ if str.match(regexp) and not str.match(other_regexp) do_something
+and you have to make this behaviour with only one regular expression. But, there exists a major problem: the complementary of a regular language might not be regular. Then, for some expression it is absolutely impossible to negate a regular expression.
+But sometimes with some simple regular expression it should be possible†. Say you want to match everything containing the some word say bull but don’t want to match bullshit. Here is a nice way to do that:
# match all string containing ‘bull’ (bullshit comprised) /bull/
/bull([^s]|)|bulls([h]|)| bullsh([^i]|)|bullshi([t]|)/
+Let look closer. In the first line the expression is: bull([^s]|$), why does the $ is needed? Because, without it the word bull would be no more matched. This expression means:
++The string finish by
+bull
+or,
+containsbullfollowed by a letter different froms.
And this is it. I hope it could help you.
+Notice this method is not always the best. For example try to write a regular expression equivalent to the following conditional expression: + # Begin with ‘a’: ^a # End with ‘a’: c$ # Contain ‘b’: .b. # But isn’t ‘axbxc’ if str.match(/^a.b.c/)andnotstr.match(/axbxc/) do_something end
+A nice solution is:
+ /abc| # length 3 a.bc| # length 4 ab.c| a[^x]b[^x]c| # length 5 a…b.c| # length >5 a.b…c/
+This solution uses the maximal length of the string not to be matched. There certainly exists many other methods. But the important lesson is it is not straightforward to exclude something of a regular expression.
+† It can be proved that any regular set minus a finite set is also regular.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ In my previous post I had given some trick to match all except something. On the same idea, the trick to match the smallest possible string. Say you want to match the string between ‘a’ and ‘b’, for example, you want to match:
++a.....a......b..b..a....a....b... ++
Here are two common errors and a solution:
++/a.*b/ +a.....a......b..b..a....a....b... ++
The first error is to use the evil .*. Because you will match from the first to the last.
+/a.*?b/ +a.....a......b..b..a....a....b... ++
The next natural way, is to change the greediness. But it is not enough as you will match from the first a to the first b. Then a simple constatation is that our matching string shouldn’t contain any a nor b. Which lead to the last elegant solution.
+/a[^ab]*b/ +a.....a......b..b..a....a....b... ++
Until now, that was, easy. Now, just pass at the case you need to match not between a and b, but between strings. For example:
This is a bit difficult. You need to match
+ +The first method would be to use the same reasoning as in my previous post. Here is a first try:
+ +But what about the following string:
+ +That string should not match. This is why if we really want to match it correctly† we need to add:
+ +Yes a bit complicated. But what if the string I wanted to match was even longer?
+Here is the algorithm way to handle this easily. You reduce the problem to the first one letter matching:
+# transform a simple randomly choosen character
+# to an unique ID
+# (you should verify the identifier is REALLY unique)
+# beware the unique ID must not contain the
+# choosen character
+s/X/_was_x_/g
+s/Y/_was_y_/g
+
+# transform the long string in this simple character
+s/<li>/X/g
+s/<\/li>/Y/g
+
+# use the first method
+s/X([^X]*)Y//g
+
+# retransform choosen letter by string
+s/X/<li>/g
+s/Y/<\/li>/g
+
+# retransform the choosen character back
+s/_was_x_/X/g
+s/_was_y_/Y/gAnd it works in only 9 lines for any beginning and ending string. This solution should look less I AM THE GREAT REGEXP M45T3R, URAN00B, but is more convenient in my humble opinion. Further more, using this last solution prove you master regexp, because you know it is difficult to manage such problems with only a regexp.
+† I know I used an HTML syntax example, but in my real life usage, I needed to match between en: and ::. And sometimes the string could finish with e::.
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Strangely enough, I didn’t find any built-in tool to split a file by keyword. I made one myself in awk. I put it here mostly for myself. But it could also helps someone else. The following code split a file for each line containing the word UTC.
#!/usr/bin/env awk BEGIN{i=0;} /UTC/ { i+=1; FIC=sprintf(“fic.%03d”,i); } {print $0>>FIC}
+In my real world example, I wanted one file per day, each line containing UTC being in the following format:
++Mon Dec 7 10:32:30 UTC 2009 ++
I then finished with the following code:
+ #!/usr/bin/env awk BEGIN{i=0;} /UTC/ { date=$1$2$3; if ( date != olddate ) { olddate=date; i+=1; FIC=sprintf(“fic.%03d”,i); } } {print $0>>FIC}
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Regular expression are really useful. Unfortunately, they are not always the best way of doing things. Particularly when transformations you want to make are easy.
+I wanted to know how to get file extension from filename the fastest way possible. There is 3 natural way of doing this:
+ # regexp str.match(/[^.]*/); ext=&
ext=str.split(‘.’)[-1]
+At first sight I believed that the regexp should be faster than the split because it could be many . in a filename. But in reality, most of time there is only one dot and I realized the split will be faster. But not the fastest way. There is a function dedicated to this work in the File module.
Here is the Benchmark ruby code:
+ #!/usr/bin/env ruby require ‘benchmark’ n=80000 tab=[ ‘/accounts/user.json’, ‘/accounts/user.xml’, ‘/user/titi/blog/toto.json’, ‘/user/titi/blog/toto.xml’ ]
And here is the result
++Get extname + user system total real +regexp: 2.550000 0.020000 2.570000 ( 2.693407) + split: 1.080000 0.050000 1.130000 ( 1.190408) + File: 0.640000 0.030000 0.670000 ( 0.717748) ++
Conclusion of this benchmark, dedicated function are better than your way of doing stuff (most of time).
+ #!/usr/bin/env ruby require ‘benchmark’ n=80000 tab=[ ‘/accounts/user.json’, ‘/accounts/user.xml’, ‘/user/titi/blog/toto.json’, ‘/user/titi/blog/toto.xml’ ]
and here is the result:
++remove extension + user system total real + File: 0.970000 0.060000 1.030000 ( 1.081398) +chomp: 0.820000 0.040000 0.860000 ( 0.947432) ++
Conclusion of the second benchmark. One simple function is better than three dedicated functions. No surprise, but it is good to know.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Standard:
+ git clone git@github.com:yogsototh/project.git
+Using HTTPS port:
+ git clone git+ssh://git@github.com:443/yogsototh/project.git
+git clone can only fetch the master branch.
If you don’t have much branches, you can simply use clone your project and then use the following command:
+ git branch –track local_branch remote_branch
+ $ git clone git@github:yogsototh/example.git $ git branch master $ git branch -a master remotes/origin/HEAD -> origin/master remotes/origin/experimental $ git branch –track experimental remotes/origin/experimental $ git branch master * experimental
+If you have many branches it can be useful to use the following script/long command line.
+ # first clone your project $ git clone git@github.com:yogsototh/project.git
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Here is a solution to maintain divergent branches in git. Because it is easy to merge by mistake. I give a script that encapsulate git in order to forbid some merge and warn you some merge should be dangerous.
+I work on a project in which some of my git branches should remain divergent. And divergences should grow.
+I also use some branch to contain what is common between projects.
+Say I have some branches:
+master: common to all branches dev: branch devoted to unstable development client: branch with features for all client but not general enough for master clientA: project adapted for client A clientB: project adapted for client B
+Here how I want to work:
+
+And more precisely the branch hierarchy:
+
+An arrow from A to B means, you can merge A in B. If there is no arrow from A to B that means it is forbidden to merge A in B. Here is the corresponding rubycode:
+ $architecture={ :master => [ :dev, :client ], :dev => [ :master ], :client => [ :clientA, :clientB ] }
+Having a :master => [ :dev, :client ] means you can merge master branch into dev and client.
If by mistake I make a git checkout master && git merge clientA, I made a mistake. This is why I made a script which encapsulate the git behaviour to dodge this kind of mistake.
But this script do far more than that. It also merge from top to down. The action allmerges will do:
git co dev && git merge master git co client && git merge master git co clientA && git merge client git co clientB && git merge client
+That means, I can update all branches. The algorithm will not make loop even if there is a cycle in the branch hierarchy.
+Here it is:
+ #!/usr/bin/env ruby # encoding: utf-8
$architecture={ :master => [ :dev, :client ], :dev => [ :master ], :client => [ :clientA, :clientB ] }
+def get_current_branch() (git branch --no-color | awk '$1 == "*" {print $2}').chop.intern end
if ARGV.length == 0 puts %{usage: $0:t [git_command or local_command]
+local commands: allmerges: merge from top to down} exit 0 end
+require ‘set’ $known_branches=Set.new $architecture.each do |k,v| $known_branches.add(k) v.each { |b| $known_branches.add(b) } end
+def rec_merge(branch) if $architecture[branch].nil? return end $architecture[branch].each do |b| if $flag.has_key?(b.to_s + branch.to_s) next end flagname=branch.to_s + b.to_s if $flag.has_key?(flagname) next end if system %{eng checkout #{b}} if get_current_branch != b puts “Can’t checkout to #{b}” exit 2 end if system %{eng merge #{branch}} $flag[flagname]=true rec_merge(b) else exit 1 end else exit 1 end end end
+def do_all_merges puts ‘Will merge from father to sons’ current_branch=get_current_branch $flag={} rec_merge(:master) system %{git co #{current_branch}} end
+def do_merge current_branch=get_current_branch src_branch=ARGV[1].intern puts %{do_merge: #{src_branch} => #{current_branch}} if $known_branches.include?(current_branch) if $known_branches.include?(src_branch) if $architecture.has_key?(src_branch) and $architecture[src_branch].include?(current_branch) system %{git merge #{src_branch}} else puts %{Forbidden merge: #{src_branch} => #{current_branch}} end else puts %{Warning! #{src_branch} not mentionned in rb configuration} sleep 2 system %{git merge #{src_branch}} puts %{Warning! #{src_branch} not mentionned in rb configuration} end end end
+case ARGV[0] when ‘allmerges’ then do_all_merges when ‘merge’ then do_merge else system %{git #{ARGV.join(’ ’)}} end +All you need to do to make it work is simply to copy eng in a directory contained in your PATH.
+Of course try to use as few as possible cherry-pick and rebase. This script was intended to work with workflow using pull and merge.
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Hi all!
+++The more you wait to do something, the more difficult it is to start doing it. {: cite=“http://www.madore.org/~david/weblog/2010-05.html#d.2010-05-12.1752” }
+
I had to write another post for this blog. I had added many article idea in my todolist. But, I made many other things, and I’ve always said (until now), I’ll do this later. What changed my mind is the haunt of this simple remark about how to be productive in programming. > Stop write TODO in your code and make it now!
+> You’ll be surprised by the results.
In short: > Just do it! ou Juste fait le comme auraient dit les nuls.
+Finally I’ll certainly write blog post more often for a short period of time.
+I finished some web services/application for gridpocket(c).
+I also finished to update my blog engine to nanoc3. The difficult part was to handle nicely multiple languages. But I should detail why in a future post.
+I also have a real life. I enjoyed some vacancies with my family.
+I work with Luc on a simple ruby REST/JSON/API oriented framework. It works fairly well, with really few bug until now. We planify to make a simple todolist tutorial. May be in two to three blog posts. This framework is not public for now. It will certainly be after we’ll create some simple web service with it and made a nice website for it.
+Then what I plan to do from now:
+There is some random in some of these achivement mostly because they don’t depend totally on me.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ hello ]*$/m,'')
+ depth-=1
+ depth.downto(0).each { |x| res<<= %{} }
+ res
+end
diff --git a/src/Scratch/en/blog/2010-05-19-How-to-cut-HTML-and-repair-it/index.html b/src/Scratch/en/blog/2010-05-19-How-to-cut-HTML-and-repair-it/index.html
new file mode 100644
index 0000000..92e0c39
--- /dev/null
+++ b/src/Scratch/en/blog/2010-05-19-How-to-cut-HTML-and-repair-it/index.html
@@ -0,0 +1,172 @@
+
+
+
+
+ For my main page, you can see, a list of my latest blog entry. And you have the first part of each article. To accomplish that, I needed to include the begining of the entry and to cut it somewhere. But now, I had to repair this cutted HTML. Here is an example: After the cut, I obtain: Argh! In the middle of an In fact, it is not as difficult as it should sound first. The secret is, you don’t need to keep the complete tree structure to repair it, but only the list of not closed parents. Given with our example, when we are after the first paragraph. we only have to close the Then, all you have to do, is not remember all the XML tree, but only the heap containing your parents. Suppose we treat the complete first example, the stack will pass through the following state, in order: The algorihm, is then really simple: ~~~~~~ {.html} let res be the XML as a string ; read res and each time you encouter a tag: if it is an opening one: push it to the stack else if it is a closing one: pop the stack. remove any malformed/cutted tag in the end of res for each tag in the stack, pop it, and write: res = res + closed tag return res ~~~~~~ And Finally, this is the code in ruby I use. The I don’t know if the code can help you, but the raisonning should definitively be known. tl;dr: : For my job, I needed to resolve a problem. It first seems not too hard. Then I started working directly on my program. I entered in the infernal: try & repair loop. Each step was like: – Just this thing to repair and that should be done. After two days of this Sisyphus work, I finally just stopped to rethink the problem. I took a pen, a sheet of paper. I simplified the problem, reminded what I learned during my Ph.D. about trees. Finally, the problem was crushed in less than 20 minutes. I believe the important lesson is to remember that the most efficient methodology to resolve this pragmatic problem was the theoretical one. And therefore, argues opposing science, theory to pragmatism and efficiency are fallacies. Apparently 90% of programmer are unable to program a binary search without bug. The algorithm is well known and easy to understand. However it is difficult to program it without any flaw. I participated to this contest. And you can see the results here1. I had to face a problem of the same kind at my job. The problem was simple to the start. Simply transform an The source and the destination format was in the following general format: At first sight I believed it will be easy. I was so certain it will be easy that I fixed to myself the following rules: You can try if you want. If you attack the problem directly opening an editor, I assure you, it will certainly be not so simple. I can tell that, because it’s what I’ve done. And I must say I lost almost a complete day at work trying to resolve this. There was also, many small problems around that make me lose more than two days for this problem. Why after two days did I was unable to resolve this problem which seems so simple? What was my behaviour (workflow)? This was a standard workflow for computer engineer. The flaw came from the first step. I thought about how to resolve the problem but with the eyes of a pragmatic engineer. I was saying: That should be a simple perl search and replace program. This is the second sentence that was plainly wrong. I started in the wrong direction. And the workflow did not work from this entry point. After some times, I just stopped to work. Tell myself “it is enough, now, I must finish it!”. I took a sheet of paper, a pen and began to draw some trees. I began by make by removing most of the verbosity. I first renamed and Then I made myself the following reflexion: Considering Tree Edit Distance, each unitary transformation of tree correspond to a simple search and replace on my One of the particularity of atomic transformations on trees, is ; if you remove a node, all children of this node, became children of its father. An example: If you delete the And look at what it implies when you write it in Then deleting all Therefore, if there exists a one state deterministic transducer which transform my trees ; I can transform the Transform this tree: to this tree: can be done using the following one state deterministic tree transducer: C -> ε Wich can be traduced by the following simple search and replace directives: Once adapted to That is all. It should seems a bit paradoxal, but sometimes the most efficient approach to a pragmatic problem is to use the theoretical methodology. I translate most of my blog entries in French and English. Most people advice me to have one file per language. Generally it ends with: This way of handling translations force you to write completely an article in one language, copy it, and translate it. However, most of time, there are common parts like images, source code, etc… When I want to correct some mistake on these parts, I have to make twice the work. With sometimes adding another mistake in only one language. This is why I preferred to handle it differently. I use tags on a single file. Finally my files looks like: As I edit my files with vim, it is really easy to add You can get my blog code source (without most of articles) at github.com/yogsototh/Scratch. I published a light version of my blog engine based on nanoc yesterday night. By light, I mean a lighter, more portable CSS (without round border). You can get it on github.com. What this system provide? Once installed (follow the README.md instructions). Now your website reside into the All files in If you want to add another language, you’ll have to modify You can separate multi content div using the: You can create div using You can create nice description table using In French all ‘:’, ‘;’, ‘!’ and ‘?’ are preceded automatically by You can use small caps using To write source code you should use the following format: ~~~~~~ {.html} ~~~~~~ {.ruby} The code ~~~~~~ The If you want to make really long blog post, you can separate them into many files. To accomplish that, you simply have to make your files like: All files are intended to be generated into the The order of post is done using the You can hide some file from the menu by setting: To know more about this blog engine, you should look at nanoc project. Then look at the files inside your project: This is a way not to count your own visits to your blog. First you should look on how I handle analytics. All analytics are handled in one javascript file, this make things really convenient. Then you need to know my method use the I check if the key then create two the other to be visible again (it can be useful): Now accessing these files with you browser you can hide or appear in your statistics. You just have to think to access these file from all you browser. Here is how to track all clicks on your website using google analytics asynchronously. First in your And here is the Replace the: To see what occurs, simply go in Happy tracking! Here is a fast and easy way to create jQuery popup. What does this code do? At the loading of the page, I create a Then when we click on a tl;dr: Before start, I must say I know Cappuccino and jQuery are no more comparable than Cocoa and the C++ standard library. One is oriented for user interface while the other is and helper for low level programming. Nonetheless I used these two to make the same web application. This is why I compare the experience I had with each of them for this specific task. I made a web version of my dashboard widget YPassword. It is a simple widget to manage your online password with a strong security and with a totally portable way. It is not intended to replace a keychain. It is more a password generator. The first was made from the code of my dashboard widget and with some jQuery. You can try it here. I then made a second version with the Cappuccino. You can try it here. If you don’t mind about what does my widget and just want to know how the two frameworkcompare, you should go directly to the next part. I manage my password on many site with a simple method. I remember a strong master password. And my password is mainly In reality I need a bit more informations to create a password: The result password is this: In fact depending of websites, some give some strange constraint to your password: And if you want to change your password the leak number is here for that. All informations such as user name, maximal length can be stored in a public file. The only real secret is the master password. If you want to know even more details you can always look at some of my old blog entries: First, I’d like to say Cappuccino applications look simply awesome. It is like having a Cocoa application in your web browser. And this is great. I also must admit I enjoyed making my application with Cappuccino. It is like programming for an iPhone application. If you are a bit familiar with Cocoa, you feel at home. If you don’t know anything about Cocoa, I suggest you to look at it. This is a really great framework to make User Interface. I am not a specialist, but I have done some MFC, java Swing1 and WXWindows User Interfaces (some years ago). And I must say, Cocoa is far better than those. Cappuccino is a great web application oriented development. But there was also some drawbacks Things I liked: Some things I didn’t like: I didn’t use bindings because I believe they are not ready by now. The jQuery version of YPassword is not as finished as the Cappuccino one. Because, there is no slider directly with jQuery. I’d have to use jQueryUI. And I believe, using it will make the application weight far more than the today 106KB. To make this version I simply copied my widget source code and adapted it. It was straightforward. But jQuery is not an application oriented framework. It is more a “dark side javascript animation framework”2. I don’t have too much to say about the jQuery version. But this was way more low level programming than Cappuccino. If you want to make an iPhone compatible web application just don’t use Cappuccino yet. If you want to make simple application like mine, I also believe, Cappuccino is a bit too much. If you want to make a complex web oriented application, Cappuccino is a great choice. But you may have some difficulties to begin programming with it. Finally, to terminate my web version of my widget, I’ll give a try to Dashcode 3. It seems to be a good alternative to create web widgets. I don’t know if Dashcode 3 is portable on non webkit browser. But if it is, it could be the end of projects like Cappuccino and Sproutcore. Some Reddit users reported my website was really long to load and to scroll. They thinks it was because of the ‘1px shadow’ I apply on all the text. I was a bit surprised, because I make some test into a really slow virtual machine. And all have always worked fine. In fact, what slow down so much are by order of importance: On Safari on Mac there is absolutely no rendering time problem. But when I use Chrome under Linux it is almost unusable. Safari and Chrome use webkit, when you access my website with javascript enabled, an additionnal browser specific CSS is loaded. Until now I switched only between: IE, Mozilla and Webkit. Now I added one more special case for Chrome. Now I continue to use gradient for Safari but no more on Chrome. I didn’t tried to verify the efficiency of all new CSS 3 features. But I advise you not to use I also detected that Many tell me to use text-shadows sparingly. But I believe it was not the real reason of the slow down. This is why I’ll get them back. Do not use <% # toremove_ %> tl;dr: I pretend to create a world to give examples of different meanings behind the word undecidability: If a demiurge made our world, he certainly had a great sense of humor. After this read, you should be convinced. I’ll pretend to be him. I’ll create a simplified world. A world that obey to simple mathematical rules. And I’ll tell you about one of the curse on this world: the undecidability. The inability to know if we had find the truth. The inability to predict many things that should be natural. Here begin the story. In the beginning there was only void. Then a blog post beginning to be written. I breath profoundly to feel the weight of the act I will accomplish. A last tense moment and… I create the Universe. An incredible Universe which will exists only the time of this read. I’m the demiurge of this universe and you are its observer. I construct this world using only simples rules. I decide that real rules of this world will be the one we believe are true for our world. Note the difference. For their world, everything we believe today is true for them. Their world is then probably simpler than our. Particularly, we can describe this world with axioms and mathematic rules. It is not so sure for our Universe. But we’ll talk about that later. Lets the work begin. I create an Earth. I populate it with intelligent people, the Ys. Of course they are curious. In particular they try to understand their world. They believe that if they know the rules of their world they will be able to predict the consequences of most of their acts. They are so naive. If only they knew. But I’m here to help them. I am a God who likes jokes. The first joke I make to Ys is to make their sense imperfect. Furthermore it is not possible to make perfect precise measure in my world. I let Ys ameliorate their technology but there is a theoretical limit to the best precision they can reach. I’d like to precise that these people believe their world is flat. Some believe it is possible to find the rules of their Universe. Now, let the game begins. Lets start easily, errors can cause undecidability. Here is what one of them think: All triangle I observe seems to share the same property. Each time I sum up their angles I obtain π radiants (180°). It is certainly a rule of my Universe. But how to be certain all triangle in my Universe share this property? Some began to formalize the problem. They end by writing a mathematical proof. Marvelous! The proof seems correct, but, a problem remains. The proof is based on rules and axioms. How to be certain these rules and axioms are right in their world? They will try to measure again and again the sum of the angles of triangles. The measure will never fail. But they’ll never be certain the rules and axioms are right. Because then only way to verify all axioms depends of observation. And as a facetious god, I forbid perfect measure in observation. Of course, they prey, they call me to help. And as any respectful god, I don’t answer. Ah ah ah! I’ve always loved to make these kind of thing. Let’s act as if I don’t exists. What a good joke! They feel sad. But they have some hope: Hope If we make small measure error, we will make small predictive error. Unfortunately, the three bodies problem will crush this hope. Using Newton’s Universal Law of gravitation with two bodies, we can predict with precision what will be their position and speed in the future. Until there all seems OK. But now, add another body. All errors will grow. Errors will grow at a point that any prediction will be unusable. Even with this bad news there is the hope to control the error. May we should know the maximal measure error we can handle to predict something. And we should at least determine what we can predict and what we cannot. Once again, this should not terminate has they hope. Consider the following question: Consider some GPS coordinates on a point around the cost of the “Bretagne” in France. The coordinates are 3 feet precise. Is the point in the water or on Earth? For some coordinates it is not possible to know. Even if we are authorize to move a bit to dodge the borders. Because there are some zone in which all point could be a “border” for any size of the zone. We can even imagine some mathematical structure where all points are at the border1. Until there all problem were undecidable because of measure errors. May be in a controlled world without any error we should be able to predict anything. It is the halting problem. Theorem: It is undecidable given a description of a program, whether the program finishes running or will run forever. The idea of the proof is simple enough to be part of this article. And this is with pleasure I give you one here. Suppose a program able to decide if any program halt exists. More precisely: Hypothesis: there exists a program Remark: Any program can be represented as a string. Therefore, a program can be used as the input of another program. It is authorized to write Let Now, what is the value of Therefore there is a contradiction the only way to handle is by the non existence of the program I am the demiurge of this imaginary world. And I cannot know the future of this world. Therefore, creative power isn’t equivalent to omnipotence. After all this, it becomes difficult to know what we can believe. But it would be another error to throw away all our knowledge. In a future next part, I’ll explain what we can hope and what attitude we should have once we’ve realized most of truth are unaccessible. Before my holidays many visitors tell me my website was too long to scroll. This is why I completely changed my website design. Now all should scroll smoothly on all platforms. I was inspired by Readability and iBooks(c) (the iPhone(c) application). Tell me what you think of this new design. I now changed my hosting to Heroku. I believe it will be far more reliable. But as you should know my website is completely static. I use nanoc to generate it. But here is the conf to make it work on heroku. The root of my files is and the Now, just follow the heroku tutorial to create an application : Now I’ll should be able to redirect properly to my own 404 page for example. I hope it is helpful. I had to send a mail using only command line. I was surprised it isn’t straightforward at all. I didn’t had What Internet say (via google) is I tried it. And it works almost each times. But for my file, it didn’t worked. I compressed it to And to obtain the “encoded” file in base64 I used: That is all. Sometimes technology is so easy to use. If I need it another time I should consider to make a shell script to automatize this. You can remark at the bottom of each page I provide a last modification date. This label was first calculated using the I use git to version my website. And fortunately I can know the last date of real change of a file. This is how I do this with nanoc: Of course I know it is really slow and absolutely not optimized. But it works as expected. Now the date you see at the bottom is exactly the date I modified the content of the page. Edit: Thanks to Eric Sunshine and Kris to provide me some hints at cleaning my code. Lets be straight: here are two functions to add to your code to have To use it, simply copy the code in your class and use as this: The I changed the design of my blog. Now it should be far cleaner. I believe I use no CSS3 feature and far less javascript. Of course before my website was perfectly browsable without javascript. Unfortunately some CSS3 feature are not mature enough on some browser. For more details you can read my older blog entry. But the major problem came from, I hope the new design please you. tl;dr: on Mac I’ve (re)discovered how to become S/MIME compliant. I am now suprised how easy it was. Some years ago it was far more difficult. Now I’m able to sign and encrypt my emails. Signing: it tell the other with an aboslute certitude the writer of the mail is you or at least used your computer. Encrypt: because sometimes you need to be 100% sure a conversation remains private. n.b.: if you use gmail, you and work not alway with a Mac, you should consider to try the gmail S/MIME firefox addon. tl;dr: Played to process a edit: I wanted this program to work only on one specific machine (a x86 on a 32 bit Ubuntu). Therefore I didn’t had any portability consideration. This is only a hack. I had to compute the sum of the absolute values of data of a I didn’t programmed in A Surprisingly, I believe that reading this kind of file is easier in To read this kind of data in Ruby, I certainly had to write a block of code for each element in the struct. But in Only one step to fill my data structure. Magic! Then, get an int value coded on two Bytes is also not a natural operation for high level language. In Finally I ended with the following code. Remark I know the wav format (16 bit / 48000Hz): Of course it is only a hack. But we can see how easy and clean it should be to improve. As I say often: the right tool for your need instead of the same tool for all your needs. Because here I am curious to know if somebody know a nice way to do this with Ruby or Python. edit: for compatibility reasons (64bit machines) used Edit (2): after most consideration about portability I made an hopefully more portable version. But I must confess this task was a bit tedious. The code remain as readable as before. But I had to use some compiler specific declaration to force the structure to be packed: Therefore this implementation should for big and little endian architecture. However, it must be compiled with Edit(3): On reddit Bogdanp proposed a Python version: and luikore proposed an impressive Ruby version: tl;dr: I made a simple macro system for my blog. Now I juste have to write %latex and it show as LaTeX. I added a macro system for my blog system. When we are used to LaTeX this lack can be hard to handle. Particularly when using mathematical notations. In the header of my files I simply write: In the body it will replace every occurrence of: The source code is really simple. For Macros could be very useful, read this article for example. Happy New Year! I was busy during the last months. But I will revive a bit this blog. I made a project to write book in markdown syntax and generating HTML and high quality PDF. I am not finished with this. I had written an efficient & simplistic MVC javascript framework. Best wishes for 2011! Update: I might change my mind now. Why? I just discovered a js2coffee converter. Furthermore Denis Knauf told me about a tl;dr: I would have loved to program client side using a Ruby-like syntax. But in the end, CoffeScript raised more disavantages than advantages. Recently I read this entry on HackerNews. The most upvoted comment praised (within other) CoffeeScript. Recently I used a lot of javascript. After trying Sproutcore, Cappuccino, looking at backbone.js & javascriptMVC, I’ve finally decided to make my own minimal javascript MVC framework.1 I had to fight the horrible syntax of javascript. It was like experiencing a back-in-time travel: It was so annoying at a point, I had thinked about creating my own CoffeeScript. I’d finished a first draft of my MVC javascript framework. Just after I learned about the existence of CoffeeScript, I immediately created a new git branch to try it. Here is my experience: Advantages: Disadvantages: The last two point were definitively really problematic for me. But even if I’ll have to work alone, I certainly won’t use CoffeeScript either. CoffeeScript is a third party and any of their update can break my code. I experienced this kind of situation many times, and it is very annoying. Far more than coding with a bad syntax. I am sad. I wanted so much to program on Web Client with a Ruby-like syntax. But in the end I think it is not for me. I have to use the horrible javascript syntax for now. At least I would have preferred a complete Typically The only way to handle this is to make the following code: Knowing this, I am now hosted on github. Diff is a very useful tool. But it is not so easy to read for us, simple mortal. This is why, when you use Here is the script I use when I want to use human readable Yesterday I was happy to make a presentation about Category Theory at Riviera Scala Clojure Meetup (note I used only Haskell for my examples). If you don't want to read them through an HTML presentations framework or downloading a big PDF
+just continue to read as a standard web page.
+ Recent Math Field Certainly one of the more abstract branches of math
+★: When is one thing equal to some other thing?, Barry Mazur, 2007 Programming is doing Math Strong relations between type theory and category theory. Not convinced? One of the goal of Category Theory is to create a homogeneous vocabulary between different disciplines. Math vocabulary used in this presentation: Category, Morphism, Associativity, Preorder, Functor, Endofunctor, Categorial property, Commutative diagram, Isomorph, Initial, Dual, Monoid, Natural transformation, Monad, Klesli arrows, κατα-morphism, ... \(\ob{\mathcal{C}}\) is a collection \(A\) and \(B\) objects of \(\C\) \(\hom{\C}\) the collection of all morphisms of \(\C\) Composition (∘): associate to each couple \(f:A→B, g:B→C\)
+ $$g∘f:A\rightarrow C$$
+ for each object \(X\), there is an \(\id_X:X→X\), Composition is associative: Two path with the same source and destination are equal. \(\ob{\C},\hom{\C}\) fixed, is there a valid ∘? Each Monoid \((M,e,⊙): \ob{M}=\{∙\},\hom{M}=M,\circ = ⊙\) Only one object. Examples: At most one morphism between two objects. Any set \(E: \ob{E}=E, \hom{x,y}=\{x\} ⇔ x=y \) Only identities A≌B means A and B are essentially the same. An endofunctor for \(\C\) is a functor \(F:\C→\C\). Categories and functors form a category: \(\Cat\) Category \(\Hask\): Forget glitches because of Put normal function inside a container. Ex: list, trees...
+
+ Haskell functor can be seen as boxes containing all Haskell types and functions.
+Haskell types look like a fractal: Haskell functor can be seen as boxes containing all Haskell types and functions.
+Haskell types look like a fractal: Haskell functor can be seen as boxes containing all Haskell types and functions.
+Haskell types look like a fractal: Let \(F\) and \(G\) be two functors from \(\C\) to \(\D\). ex: between Haskell functors; tl;dr: How I use hakyll. Abbreviations, typography corrections, multi-language, use This website is done with Hakyll. Hakyll can be considered as a minimal cms. But more generally it is a library helping file generation. We can view it as an advanced build system (like From the user perspective I blog this way: Being short sighted one could reduce the role of Hakyll to: create (resp. update) html file when I create (resp. change) a markdown file. While it sounds easy, there are a lot of hidden details: The work of Hakyll is to help you with these. But let’s start with the basic concepts. For each file you create, you have to provide: First, let’s start with the simplest case: static files (images, fonts, etc…). Generally, you have a source directory (here is the current directory) and a destination directory The Hakyll code is: This program will copy If you create a file If the file the file But horror! Now if our See, it’s easy But we have a problem. How could we change the title or add keywords? The solution is to use And modify slightly our template: As Sir Robin said just before dying before the Bridge of Death: “That’s EASY!” – Sir Robin, the Not-Quite-So-Brave-As-Sir-Lancelot Now that we understand the basic functionality. How to: That’s easy. Simply call the executable using In order to help to reference your website on the web, it is nice to add some keywords as meta datas to your html page. In order to add keywords, we could not directly use the markdown metadatas. Because, without any, there should be any meta tag in the html. An easy answer is to create a Then we pass this ☞ Here are the imports I use for this tutorial. What I mean is to use url of the form: I prefer this than having to add file with Not too difficult. But! There might be a problem. What if there is a Very simple, we simply remove all And we apply this filter at the end of our compilation Creating an archive start to be difficult. There is an example in the default Hakyll example. Unfortunately, it assumes all posts prefix their name with a date like in I migrated from an older blog and didn’t want to change my url. Also I prefer not to use any filename convention. Therefore, I add the date information in the metadata Where And Here is how it is done: It wasn’t so easy. But it works pretty well. To create an rss feed, we have to: We could then render the posts twice. One for html rendering and another time for rss. Remark we need to generate the rss version to create the html one. One of the great feature of Hakyll is to be able to save snapshots. Here is how: Now for each post there is a snapshot named “content” associated. The snapshots are created before applying a template and after applying pandoc. Furthermore feed don’t need a source markdown file. Then we create a new file from no one. Instead of using The Great idea certainly steal from nanoc (my previous blog engine)! As I just said, nanoc was my preceding blog engine. It is written in Ruby and as Hakyll, it is quite awesome. And one thing Ruby does more naturally than Haskell is regular expressions. I had a lot of filters in nanoc. I lost some because I don’t use them much. But I wanted to keep some. Generally, filtering the content is just a way to apply to the body a function of type Also we generally want prefilters (to filter the markdown) and postfilters (to filter the html after the pandoc compilation). Here is how I do it: Where Now we have a simple way to filter the content. Let’s augment the markdown ability. Comparing to LaTeX, a very annoying markdown limitation is the lack of abbreviations. Fortunately we can filter our content. And here is the filter I use: It will search for all string starting by ‘%’ and it will search in the Do you really believe I type each time I write LaTeX? Generally I write my post in English and French. And this is more difficult than it appears. For example, I need to filter the language in order to get the right list of posts. I also use some words in the templates and I want them to be translated. First I create a Map containing all translations. Then I create a context for all key: The full code is here. And except from the main file, I use literate Haskell. This way the code should be easier to understand. If you want to know why I switched from nanoc: My preceding nanoc website was a bit too messy. So much in fact, that the dependency system recompiled the entire website for any change. So I had to do something about it. I had two choices: I added too much functionalities in my nanoc system. Starting from scratch (almost) remove efficiently a lot of unused crap. So far I am very happy with the switch. A complete build is about 4x faster. I didn’t broke the dependency system this time. As soon as I modify and save the markdown source, I can reload the page in the browser. I removed a lot of feature thought. Some of them will be difficult to achieve with Hakyll. A typical example: In nanoc I could take a file like this as source: And it will create a file We could also add the metadatas in an external file ( Here is the obfuscated code: To launch it, you’ll need to have haskell installed and to run: Here is some image after 50 iterations: Here is the more readable version. I believe with this far more readable version, no more explanation is needed. tl;dr: A progressive Haskell example. A Mandelbrot set extended in 3D, rendered using OpenGL and coded with Haskell. In the end the code will be very clean. The significant stuff will be in a pure functional bubble. The display details will be put in an external module playing the role of a wrapper. Imperative language could also benefit from this functional organization. In my preceding article I introduced Haskell. This article goes further. It will show how to use functional programming with interactive programs. But more than that, it will show how to organize your code in a functional way. This article is more about functional paradigm than functional language. The code organization can be used in most imperative language. As Haskell is designed for functional paradigm, it is easier to use in this context. In reality, the firsts sections will use an imperative paradigm. As you can use functional paradigm in imperative language, you can also use imperative paradigm in functional languages. This article is about creating an useful and clean program. It can interact with the user in real time. It uses OpenGL, a library with imperative programming foundations. Despite this fact, most of the final code will remain in the pure part (no I believe the main audience for this article are: I had in mind for some time now to make a Mandelbrot set explorer. I had already written a command line Mandelbrot set generator in Haskell. This utility is highly parallel; it uses the This time, we will not parallelize the computation. Instead, we will display the Mandelbrot set extended in 3D using OpenGL and Haskell. You will be able to move it using your keyboard. This object is a Mandelbrot set in the plan (z=0), and something nice to see in 3D. Here are some screenshots of the result: And you can see the intermediate steps to reach this goal: From the 2nd section to the 4th it will be dirtier and dirtier. We start cleaning the code at the 5th section. Download the source code of this section → 01_Introduction/hglmandel.lhs We can consider two parts. The first being mostly some boilerplate2. And the second part more focused on OpenGL and content. For efficiency reason3, I will not use the default Haskell We declare some useful functions for manipulating complex numbers: We start by giving the main architecture of our program: Mainly, we initialize our OpenGL application. We declared that the function Also here, there is only one interesting line; the draw will occur in the function This function will provide a list of draw actions. Remember that OpenGL is imperative by design. Then, one of the consequence is you must write the actions in the right order. No easy parallel drawing here. Here is the function which will render something on the screen: The We also need some kind of global variables. In fact, global variable are a proof of a design problem. We will get rid of them later. And of course our list of colored points. In OpenGL the default coordinate are from -1 to 1. We need a function which transform an integer value to some color: And now the It uses the main Mandelbrot function for each complex \(c\). The Mandelbrot set is the set of complex number \(c\) such that the following sequence does not escape to infinity. Let us define \(f_c: \) The sequence is: Of course, instead of trying to test the real limit, we just make a test after a finite number of occurrences. Well, if you download this file (look at the bottom of this section), compile it and run it this is the result: A first very interesting property of this program is that the computation for all the points is done only once. It is a bit long before the first image appears, but if you resize the window, it updates instantaneously. This property is a direct consequence of purity. If you look closely, you see that See what occurs if we make the window bigger: We see some black lines because we have drawn less point than there is on the surface. We can repair this by drawing little squares instead of just points. But, instead we will do something a bit different and unusual. Download the source code of this section → 01_Introduction/hglmandel.lhs Download the source code of this section → 02_Edges/HGLMandelEdge.lhs This time, instead of drawing all points, we will simply draw the edges of the Mandelbrot set. The method I use is a rough approximation. I consider the Mandelbrot set to be almost convex. The result will be good enough for the purpose of this tutorial. We change slightly the And now, we should change our list of points. Instead of drawing every point of the visible surface, we will choose only point on the surface. We only need to compute the positive point. The Mandelbrot set is symmetric relatively to the abscisse axis. This function is interesting. For those not used to the list monad here is a natural language version of this function: In fact using the list monad you write like if you consider only one element at a time and the computation is done non deterministically. To find the smallest number such that No rocket science here. See the result now: Download the source code of this section → 02_Edges/HGLMandelEdge.lhs Download the source code of this section → 03_Mandelbulb/Mandelbulb.lhs Now we will we extend to a third dimension. But, there is no 3D equivalent to complex. In fact, the only extension known are quaternions (in 4D). As I know almost nothing about quaternions, I will use some extended complex, instead of using a 3D projection of quaternions. I am pretty sure this construction is not useful for numbers. But it will be enough for us to create something that look nice. This section is quite long, but don’t be afraid, most of the code is some OpenGL boilerplate. If you just want to skim this section, here is a high level representation: We declare a new type The most important part is the new multiplication instance. Modifying this formula will change radically the shape of the result. Here is the formula written in a more mathematical notation. I called the third component of these extended complex strange. Note how if \(z=z’=0\) then the multiplication is the same to the complex one. As we will use some 3D, we add some new directive in the boilerplate. But mainly, we simply state that will use some depth buffer. And also we will listen the keyboard. The We introduce some helper function to manipulate standard And we use them to code the function handling keyboard. We will use the keys Note Not much to say about this function. Mainly there are two parts: apply some transformations, draw the object. We have finished with the OpenGL section, let’s talk about how we generate the 3D points and colors. First, we will set the number of details to 200 pixels in the three dimensions. This time, instead of just drawing some line or some group of points, we will show triangles. The function In fact, we will provide six ordered points. These points will be used to draw two triangles. The next function is a bit long. Here is an approximative English version: Also, I added a test to hide points too far from the border. In fact, this function show points close to the surface of the modified mandelbrot set. But not the mandelbrot set itself. If you look at the function above, you see a lot of common patterns. Haskell is very efficient to make this better. Here is a harder to read but shorter and more generic rewritten function: If you prefer the first version, then just imagine how hard it will be to change the enumeration of the point from (x,y) to (x,z) for example. Also, we didn’t searched for negative values. This modified Mandelbrot is no more symmetric relatively to the plan The rest of the program is very close to the preceding one. We simply add a new dimension to the Here is the result: Download the source code of this section → 03_Mandelbulb/Mandelbulb.lhs Download the source code of this section → 04_Mandelbulb/Mandelbulb.lhs The first approach to clean the code is to separate the GLUT/OpenGL part from the computation of the shape. Here is the cleaned version of the preceding section. Most boilerplate was put in external files. The We set some global constant (this is generally bad). We then generate colored points from our function. This is similar to the preceding section. This code is cleaner but many things doesn’t feel right. First, all the user interaction code is outside our main file. I feel it is okay to hide the detail for the rendering. But I would have preferred to control the user actions. On the other hand, we continue to handle a lot rendering details. For example, we provide ordered vertices. Download the source code of this section → 04_Mandelbulb/Mandelbulb.lhs Download the source code of this section → 05_Mandelbulb/Mandelbulb.lhs Some points: OpenGL and GLUT is done in C. In particular the Our main problem come from user interaction. If you ask “the Internet”, about how to deal with user interaction with a functional paradigm, the main answer is to use functional reactive programming (FRP). I won’t use FRP in this article. Instead, I’ll use a simpler while less effective way to deal with user interaction. But The method I’ll use will be as pure and functional as possible. Here is how I imagine things should go. First, what the main loop should look like if we could make our own: Clearly, ideally we should provide only three parameters to this main loop function: Here is a real working code, I’ve hidden most display functions. The YGL, is a kind of framework to display 3D functions. But it can easily be extended to many kind of representation. We first set the mapping between user input and actions. The type of each couple should be of the form And of course a type design the World State. The important part is that it is our World State type. We could have used any kind of data type. The important part to glue our own type to the framework is to make our type an instance of the type class The We also need to set all our transformation functions. These function are used to update the world state. Note The resize is used to generate the 3D function. As I wanted the time spent to generate a more detailed view to grow linearly I use this not so straightforward formula. The Here is our initial world state. We will define Now the function which will generate points in 3D. The first parameter ( The type With the color function. The rest is similar to the preceding sections. I won’t explain how the magic occurs here. If you are interested, just read the file Download the source code of this section → 05_Mandelbulb/Mandelbulb.lhs Download the source code of this section → 06_Mandelbulb/Mandelbulb.lhs Our code architecture feel very clean. All the meaningful code is in our main file and all display details are externalized. If you read the code of Before our program structure was: Now we have The World state could change. The compiler can no more optimize the computation for us. We have to manually explain when to redraw the shape. To optimize we must do some things in a lower level. Mostly the program remains the same, but it will provide the list of atoms directly. Our initial world state is slightly changed: The use of We use the We know that resize is the only world change that necessitate to recompute the list of atoms (triangles). Then we update our world state accordingly. All the rest is exactly the same. And you can also consider minor changes in the Download the source code of this section → 06_Mandelbulb/Mandelbulb.lhs As we can use imperative style in a functional language, know you can use functional style in imperative languages. This article exposed a way to organize some code in a functional way. I’d like to stress the usage of Haskell made it very simple to achieve this. Once you are used to pure functional style, it is hard not to see all advantages it offers. The code in the two last sections is completely pure and functional. Furthermore I don’t use The If you want to go further, it shouldn’t be hard to add parallelism. This should be easy mainly because most of the visible code is pure. Such an optimization would have been harder by using directly the OpenGL library. You should also want to make a more precise object. Because, the Mandelbulb is clearly not convex. But a precise rendering might be very long from O(n².log(n)) to O(n³). Unfortunately, I couldn’t make this program to work on my Mac. More precisely, I couldn’t make the DevIL library work on Mac to output the image. Yes I have done a Generally in Haskell you need to declare a lot of import lines. This is something I find annoying. In particular, it should be possible to create a special file, Import.hs which make all the necessary import for you, as you generally need them all. I understand why this is cleaner to force the programmer not to do so, but, each time I do a copy/paste, I feel something is wrong. I believe this concern can be generalized to the lack of namespace in Haskell.↩ I tried tl;dr: Some hints on how to make great documentation for Haskell libraries. Great documentation make a big difference. A bad documentation could simply make people not using your lib. My friend was learning Haskell. To start he tried a Haskell library to make a small application. The documentation was deprecated to the point he wasn’t able to make a basic example work. How do you believe he felt? What does he thought about Haskell in general? So here are my hint on how to make a great documentation in Haskell. Documentation can take many different form. To prevent obsolescence of your tutorial, use That way when you’ll do a To use And to make it works simply verify you have a and in Now There are plenty of alternative solution. I provide the one I believe would be used by most people. So if you use Add a If you are afraid by such its complexity you might just want to use this one: Don’t forget to activate your repo in travis. For some bonus points add the build status badge in your Congratulation! Now if you break your documentation examples, you’ll get notified. You could add badges to your Here is a list of some: If you didn’t declared your package to See Stackage Badges for more informations. If you use So edit your And then you can create a new projec with: Even not doing anything, if you submit your library to hackage, haddock should generate some API documentation for free. But to make real documentation you need to add some manual annotations. Functions: Data: Module: Documentation Structure: That will generate headings. In Haskell we have great tools like And But generally we lack a lot of Tutorials and Guides. This post was an attempt to help people making more of them. But there are other good ideas to help improve the situation. In clojure when you create a new project using If you try to search for some clojure function on a search engine there is a big chance the first result will link to: For each symbol necessiting a documentation. You don’t only have the details and standard documentation. You’ll also get: Most of the time, if you google the function you search you end up on clojuredocs for wich there are many contributions. Currently stackage is closer to these feature than hackage. Because on stackage you have access to the README and also some comments by package. I believe it would be more efficient to have at least a page by module and why not a page by symbol (data, functions, typeclasses…). For example, we could provide details about Today, if you want to help documenting, you need to make a PR to the source of some library. While if we had an equivalent to clojuredocs for Haskell, adding documentation would simply be a few clicks away: There are more than 23k people on And last but not least, Design is a vague word. A good design should care not only about how something look, but also how users will interact with it. For example by removing things to focus on the essential. When I stumble upon some random blog post or random specification in the Haskell community, I had too much a feeling of old fashioned design. If you look at node.js community lot of their web page look cleaner, easier to read and in the end, more user friendly. Haskell is very different from node, I wouldn’t like to replace all long and precise documentation with short human unprecise concepts. I don’t want to transform scientific papers by tweets. But like the scientific community has upgraded with the use of LaTeX, I believe we could find something similar that would make, very clean environment for most of us. A kind of look and feel that will be tl;dr: A very short and dense tutorial for learning Haskell. Thanks to: I really believe all developers should learn Haskell. I don’t think everyone needs to be super Haskell ninjas, but they should at least discover what Haskell has to offer. Learning Haskell opens your mind. Mainstream languages share the same foundations: Haskell is very different. The language uses a lot of concepts I had never heard about before. Many of those concepts will help you become a better programmer. But learning Haskell can be hard. It was for me. In this article I try to provide what I lacked during my learning. This article will certainly be hard to follow. This is on purpose. There is no shortcut to learning Haskell. It is hard and challenging. But I believe this is a good thing. It is because it is hard that Haskell is interesting. The conventional method to learning Haskell is to read two books. First “Learn You a Haskell” and just after “Real World Haskell”. I also believe this is the right way to go. But to learn what Haskell is all about, you’ll have to read them in detail. In contrast, this article is a very brief and dense overview of all major aspects of Haskell. I also added some information I lacked while I learned Haskell. The article contains five parts: Some might not work, but most will. You should see a link just below. 01_basic/10_Introduction/00_hello_world.lhs There are different way to install Haskell, I would recommend to use There are other way to install Haskell on your system you could visit, you can learn more about it by visiting haskell.org or haskell-lang.org Tools: Many books/articles about Haskell start by introducing some esoteric formula (quick sort, Fibonacci, etc…). I will do the exact opposite. At first I won’t show you any Haskell super power. I will start with similarities between Haskell and other programming languages. Let’s jump to the mandatory “Hello World”. To run it, you can save this code in a or if you use You could also download the literate Haskell source. You should see a link just above the introduction title. Download this file as 01_basic/10_Introduction/00_hello_world.lhs 01_basic/10_Introduction/10_hello_you.lhs Now, a program asking your name and replying “Hello” using the name you entered: First, let us compare this with similar programs in a few imperative languages: The structure is the same, but there are some syntax differences. The main part of this tutorial will be dedicated to explaining why. In Haskell there is a Just remember that Haskell can look a lot like mainstream imperative languages. 01_basic/10_Introduction/10_hello_you.lhs 01_basic/10_Introduction/20_very_basic.lhs Before continuing you need to be warned about some essential properties of Haskell. Functional Haskell is a functional language. If you have an imperative language background, you’ll have to learn a lot of new things. Hopefully many of these new concepts will help you to program even in imperative languages. Smart Static Typing Instead of being in your way like in Purity Generally your functions won’t modify anything in the outside world. This means they can’t modify the value of a variable, can’t get user input, can’t write on the screen, can’t launch a missile. On the other hand, parallelism will be very easy to achieve. Haskell makes it clear where effects occur and where your code is pure. Also, it will be far easier to reason about your program. Most bugs will be prevented in the pure parts of your program. Furthermore, pure functions follow a fundamental law in Haskell: Applying a function with the same parameters always returns the same value. Laziness Laziness by default is a very uncommon language design. By default, Haskell evaluates something only when it is needed. In consequence, it provides a very elegant way to manipulate infinite structures, for example. A last warning about how you should read Haskell code. For me, it is like reading scientific papers. Some parts are very clear, but when you see a formula, just focus and read slower. Also, while learning Haskell, it really doesn’t matter much if you don’t understand syntax details. If you meet a You might be used to declaring functions like this: In In JavaScript: in Python: in Ruby: In Scheme: Finally, the Haskell way is: Very clean. No parenthesis, no Don’t forget, Haskell uses functions and types a lot. It is thus very easy to define them. The syntax was particularly well thought out for these objects. Although it is not mandatory, type information for functions is usually made explicit. It’s not mandatory because the compiler is smart enough to discover it for you. It’s a good idea because it indicates intent and understanding. Let’s play a little. We declare the type using 01_basic/10_Introduction/20_very_basic.lhs 01_basic/10_Introduction/21_very_basic.lhs Now try You should get this error: The problem: 01_basic/10_Introduction/21_very_basic.lhs 01_basic/10_Introduction/22_very_basic.lhs The solution: don’t declare a type for It works! Luckily, we don’t have to declare a new function for every single type. For example, in But, what type should we declare? To discover the type Haskell has found for us, just launch ghci: Uh? What is this strange type? First, let’s focus on the right part In the type So instead of having a forced type like in This is sometimes called parametric polymorphism. It’s also called having your cake and eating it too. Generally Type classes are a very powerful language construct. We can do some incredibly powerful stuff with this. More on this later. Finally, Let Yes, strange. In fact, in Haskell no function really has two arguments. Instead all functions have only one argument. But we will note that taking two arguments is equivalent to taking one argument and returning a function taking the second argument as a parameter. More precisely Another notation exists for functions. The lambda notation allows us to create functions without assigning them a name. We call them anonymous functions. We could also have written: The If you are not used to functional programming your brain should be starting to heat up. It is time to make a real application. 01_basic/10_Introduction/22_very_basic.lhs 01_basic/10_Introduction/23_very_basic.lhs But just before that, we should verify the type system works as expected: It works, because, 01_basic/10_Introduction/23_very_basic.lhs 01_basic/10_Introduction/24_very_basic.lhs If we force our function to work with different types, it will fail: The compiler complains. The two parameters must have the same type. If you believe that this is a bad idea, and that the compiler should make the transformation from one type to another for you, you should really watch this great (and funny) video: WAT 01_basic/10_Introduction/24_very_basic.lhs I suggest that you skim this part. Think of it as a reference. Haskell has a lot of features. A lot of information is missing here. Come back here if the notation feels strange. I use the Yeah! And also rational numbers FTW! But you need to import the module In Haskell strings are list of Remark: In real code you shouldn’t use list of char to represent text. You should mostly use The type of couple is To remove some parentheses you can use two functions: 01_basic/20_Essential_Haskell/10a_Functions.lhs Just a reminder: Remember that defining the type of a function before its declaration isn’t mandatory. Haskell infers the most general type for you. But it is considered a good practice to do so. Infix notation Note We can remove Note we can declare functions with Tests An implementation of the absolute function. Note: the Another equivalent version: Notation warning: indentation is important in Haskell. Like in Python, bad indentation can break your code! 01_basic/20_Essential_Haskell/10a_Functions.lhs The hard part can now begin. In this section, I will give a short example of the impressive refactoring ability provided by Haskell. We will select a problem and solve it in a standard imperative way. Then I will make the code evolve. The end result will be both more elegant and easier to adapt. Let’s solve the following problem: Given a list of integers, return the sum of the even numbers in the list. example: To show differences between functional and imperative approaches, I’ll start by providing an imperative solution (in JavaScript): In Haskell, by contrast, we don’t have variables or a for loop. One solution to achieve the same result without loops is to use recursion. Remark: Recursion is generally perceived as slow in imperative languages. But this is generally not the case in functional programming. Most of the time Haskell will handle recursive functions efficiently. Here is a Keep this code in mind. We will translate it into Haskell. First, however, I need to introduce three simple but useful functions we will use: Note that for any non empty list The first Haskell solution. The function To test a function you can use Here is an example of execution2: Coming from an imperative language all should seem right. In fact, many things can be improved here. First, we can generalize the type. Next, we can use sub functions using Next, we can use pattern matching. What is pattern matching? Use values instead of general parameter names3. Instead of saying: But pattern matching goes even further. It is also able to inspect the inner data of a complex value. We can replace with This is a very useful feature. It makes our code both terser and easier to read. In Haskell you can simplify function definitions by η-reducing them. For example, instead of writing: you can simply write We use this method to remove the To make things even better we should use higher order functions. What are these beasts? Higher order functions are functions taking functions as parameters. Here are some examples: Let’s proceed by small steps. where The function Our next step is to use another technique to accomplish the same thing as a loop. We will use the Which can be replaced by: If you really want to know how the magic works, here is the definition of But as Haskell is lazy, it doesn’t evaluate Now our new version of We can also simplify this by using directly a lambda notation. This way we don’t have to create the temporary name And of course, we note that Finally To help you understand what’s going on here, let’s look at a step by step evaluation: Another useful higher order function is We can take advantage of this operator to η-reduce our function: Also, we could rename some parts to make it clearer: It is time to discuss the direction our code has moved as we introduced more functional idioms. What did we gain by using higher order functions? At first, you might think the main difference is terseness. But in fact, it has more to do with better thinking. Suppose we want to modify our function slightly, for example, to get the sum of all even squares of elements of the list. Updating version 10 is extremely easy: We just had to add another “transformation function”[^0216]. The We didn’t have to modify anything inside the function definition. This makes the code more modular. But in addition you can think more mathematically about your function. You can also use your function interchangably with others, as needed. That is, you can compose, map, fold, filter using your new function. Modifying version 1 is left as an exercise to the reader ☺. If you believe we have reached the end of generalization, then know you are very wrong. For example, there is a way to not only use this function on lists but on any recursive type. If you want to know how, I suggest you to read this quite fun article: Functional Programming with Bananas, Lenses, Envelopes and Barbed Wire by Meijer, Fokkinga and Paterson. This example should show you how great pure functional programming is. Unfortunately, using pure functional programming isn’t well suited to all usages. Or at least such a language hasn’t been found yet. One of the great powers of Haskell is the ability to create DSLs (Domain Specific Language) making it easy to change the programming paradigm. In fact, Haskell is also great when you want to write imperative style programming. Understanding this was really hard for me to grasp when first learning Haskell. A lot of effort tends to go into explaining the superiority of the functional approach. Then when you start using an imperative style with Haskell, it can be hard to understand when and how to use it. But before talking about this Haskell super-power, we must talk about another essential aspect of Haskell: Types. tl;dr: In Haskell, types are strong and static. Why is this important? It will help you greatly to avoid mistakes. In Haskell, most bugs are caught during the compilation of your program. And the main reason is because of the type inference during compilation. Type inference makes it easy to detect where you used the wrong parameter at the wrong place, for example. Static typing is generally essential for fast execution. But most statically typed languages are bad at generalizing concepts. Haskell’s saving grace is that it can infer types. Here is a simple example, the This function can Now compare with the amount of code necessary in C: For each type, you need to write a new function. The only way to work around this problem is to use some meta-programming trick, for example using the pre-processor. In C++ there is a better way, C++ templates: C++ does a far better job than C in this regard. But for more complex functions the syntax can be hard to follow: see this article for example. In C++ you must declare that a function can work with different types. In Haskell, the opposite is the case. The function will be as general as possible by default. Type inference gives Haskell the feeling of freedom that dynamically typed languages provide. But unlike dynamically typed languages, most errors are caught before run time. Generally, in Haskell: “if it compiles it certainly does what you intended” You can construct your own types. First, you can use aliases or type synonyms. But it doesn’t protect you much. Try to swap the two parameter of It will compile and execute. In fact you can replace Name, Color and String everywhere. The compiler will treat them as completely identical. Another method is to create your own types using the keyword Now if you switch parameters of Also notice that constructors are functions: The syntax of Generally the usage is to use the same name for the DataTypeName and DataTypeConstructor. Example: Also you can use the record syntax: And many accessors are made for you. Furthermore you can use another order when setting values. Example: You already encountered a recursive type: lists. You can re-create lists, but with a more verbose syntax: If you really want to use an easier syntax you can use an infix name for constructors. The number after If you want to be able to print ( When you add This prints: We’ll just give another standard example: binary trees. We will also create a function which turns a list into an ordered binary tree. Look at how elegant this function is. In plain English: You should obtain the following: This is an informative but quite unpleasant representation of our tree. Just for fun, let’s code a better display for our trees. I simply had fun making a nice function to display trees in a general way. You can safely skip this part if you find it too difficult to follow. We have a few changes to make. We remove the Without the Here is my version of how to show a binary tree. Don’t worry about the apparent complexity. I made a lot of improvements in order to display even stranger objects. The And now, we can play: Now it is far better! The root is shown by starting the line with the As we can test equality and order trees, we can make tree of trees! This is why I chose to prefix each line of tree display by Which is equivalent to and gives: Notice how duplicate trees aren’t inserted; there is only one tree corresponding to See how awesome this structure is: We can make trees containing not only integers, strings and chars, but also other trees. And we can even make a tree containing a tree of trees! 02_Hard_Part/40_Infinites_Structures.lhs It is often said that Haskell is lazy. In fact, if you are a bit pedantic, you should say that Haskell is non-strict. Laziness is just a common implementation for non-strict languages. Then what does “not-strict” mean? From the Haskell wiki: Reduction (the mathematical term for evaluation) proceeds from the outside in. so if you have For example in Haskell you can do: And it stops. How? Instead of trying to evaluate Also, note in Haskell there is a notation for infinite lists and most functions will work with them. Also, there is a built-in function 02_Hard_Part/40_Infinites_Structures.lhs 02_Hard_Part/41_Infinites_Structures.lhs Suppose we don’t mind having an ordered binary tree. Here is an infinite binary tree: A complete binary tree where each node is equal to 0. Now I will prove you can manipulate this object using the following function: See what occurs for this program: This code compiles, runs and stops giving the following result: Just to heat up your neurones a bit more, let’s make a slightly more interesting tree: Another way to create this tree is to use a higher order function. This function should be similar to Hint: I won’t talk more about this here. If you are interested in the generalization of Our definition is now: Look at the result for 02_Hard_Part/41_Infinites_Structures.lhs Congratulations for getting so far! Now, some of the really hardcore stuff can start. If you are like me, you should get the functional style. You should also understand a bit more the advantages of laziness by default. But you also don’t really understand where to start in order to make a real program. And in particular: Be prepared, the answers might be complex. But they are all very rewarding. 03_Hell/01_IO/01_progressive_io_example.lhs tl;dr: A typical function doing In this section, I will explain how to use IO, not how it works. You’ll see how Haskell separates the pure from the impure parts of the program. Don’t stop because you’re trying to understand the details of the syntax. Answers will come in the next section. What to achieve? Ask a user to enter a list of numbers. Print the sum of the numbers It should be straightforward to understand the behavior of this program. Let’s analyze the types in more detail. Or more interestingly, we note that each expression in the We should also pay attention to the effect of the If Another important note about using ou These two kinds of line will correspond to two different ways of sequencing actions. The meaning of this sentence should be clearer by the end of the next section. 03_Hell/01_IO/01_progressive_io_example.lhs 03_Hell/01_IO/02_progressive_io_example.lhs Now let’s see how this program behaves. For example, what happens if the user enters something strange? Let’s try: Argh! An evil error message and a crash! Our first improvement will simply be to answer with a more friendly message. In order to do this, we must detect that something went wrong. Here is one way to do this: use the type What is this thing? This is a nice way to tell there was an error while trying to create/compute a value. The Now to be a bit more readable, we define a function which goes like this: If the string has the wrong format, it will return We simply have to test the value in our main function. In case of error, we display a nice error message. Note that the type of each expression in the main’s One very important thing to note is the type of all the functions defined so far. There is only one function which contains Why does purity matter? Among the many advantages, here are three: This is why you should generally put as most code as possible inside pure functions. 03_Hell/01_IO/02_progressive_io_example.lhs 03_Hell/01_IO/03_progressive_io_example.lhs Our next iteration will be to prompt the user again and again until she enters a valid answer. We keep the first part: Now we create a function which will ask the user for an list of integers until the input is right. This function is of type «This is an If you want to understand the details behind all of this, you’ll have to read the next section. But really, if you just want to use IO just practice a little and remember to think about the type. Finally our main function is much simpler: We have finished with our introduction to If you practice a bit, you should be able to use Exercises: 03_Hell/01_IO/03_progressive_io_example.lhs Here is a tl;dr: for this section. To separate pure and impure parts, A function is guaranteed to have side effects only if it has this type. But look at a typical main function: We have a lot of temporary elements (here We create a function Bonus: Haskell has syntactical sugar for us: Why did we use this strange syntax, and what exactly is this For now let’s just forget all about the pure parts of our program, and focus on the impure parts: First remark: this looks imperative. Haskell is powerful enough to make impure code look imperative. For example, if you wish you could create a But you should have noticed that the notation is a bit unusual. Here is why, in detail. In an impure language, the state of the world can be seen as a huge hidden global variable. This hidden variable is accessible by all functions of your language. For example, you can read and write a file in any function. Whether a file exists or not is a difference in the possible states that the world can take. In Haskell the current state of the world is not hidden. Rather, it is explicitly said that Not all functions may access this variable. Those which have access to this variable are impure. Functions to which the world variable isn’t provided are pure5. Haskell considers the state of the world as an input variable to The Now let’s rewrite our main function with this in mind: First, we note that all functions which have side effects must have the type: where Another thing to note is the trick to fix the order of evaluation. In Haskell, in order to evaluate This is true because we’re working in a pure part of the language. Now, if you look at the main function, it is clear you must eval the first line before the second one since to evaluate the second line you have to get a parameter given by the evaluation of the first line. This trick works like a charm. The compiler will at each step provide a pointer to a new real world id. Under the hood, Now, if you look at the style of the main function, it is clearly awkward. Let’s try to do the same to the Before: After: This is similar, but awkward. Look at all these temporary The lesson is: naive IO implementation in Pure functional languages is awkward! Fortunately, there is a better way to handle this problem. We see a pattern. Each line is of the form: Even if for some lines the first Not only this, but we can also note that we always follow the same usage pattern: Each action can take from 0 to n parameters. And in particular, each action can take a parameter from the result of a line above. For example, we could also have: With, of course: IMPORTANT: there are only two important patterns to consider: and Now, we will do a magic trick. We will make the temporary world symbols “disappear”. We will But remember that Some examples of functions: The function This new It says that Now, remember the important patterns. The first was: Look at the types: Doesn’t it seem familiar? The idea is to hide the World argument with this function. Let’s go: As an example imagine if we wanted to simulate: Now, using the As print is of type Which is equivalent to: Didn’t you notice something? Yes, no temporary World variables are used anywhere! This is MA. GIC. We can use a better notation. Let’s use fr; Haskell a confectionné du sucre syntaxique pour vous : Ho Ho Ho! Merry Christmas Everyone! Haskell has made syntactical sugar for us: Is replaced by: Note that you can use But what about the lines not using the I didn’t simplify this definition for the purposes of clarity. Of course, we can use a better notation: we’ll use the And Is transformed into Also, another function is quite useful. This is the general way to put pure values inside the “IO context”. The general name for 03_Hell/01_IO/21_Detailled_IO.lhs To finish, let’s translate our example: Is translated into: You can compile this code to verify that it works. Imagine what it would look like without the 03_Hell/01_IO/21_Detailled_IO.lhs 03_Hell/02_Monads/10_Monads.lhs Now the secret can be revealed: Important remarks: In Haskell, Remarks: There are a lot of different types that are instances of Imagine a complex bank operation. You are eligible to gain about 700€ only if you can afford to follow a list of operations without your balance dipping below zero. 03_Hell/02_Monads/10_Monads.lhs 03_Hell/02_Monads/11_Monads.lhs Now, let’s make it better using Maybe and the fact that it is a Monad 03_Hell/02_Monads/11_Monads.lhs 03_Hell/02_Monads/12_Monads.lhs Not bad, but we can make it even better: We have proven that Monads are a good way to make our code more elegant. Note this idea of code organization, in particular for An important remark: The first element in the sequence being evaluated to You could also replay these example with the definition of The 03_Hell/02_Monads/12_Monads.lhs 03_Hell/02_Monads/13_Monads.lhs The list monad helps us to simulate non-deterministic computations. Here we go: MA. GIC. : For the list monad, there is also this syntactic sugar: I won’t list all the monads, since there are many of them. Using monads simplifies the manipulation of several notions in pure languages. In particular, monads are very useful for: If you have followed me until here, then you’ve done it! You know monads7! 03_Hell/02_Monads/13_Monads.lhs This section is not so much about learning Haskell. It is just here to discuss some details further. 04_Appendice/01_More_on_infinite_trees/10_Infinite_Trees.lhs In the section Infinite Structures we saw some simple constructions. Unfortunately we removed two properties from our tree: In this section we will try to keep the first property. Concerning the second one, we must relax it but we’ll discuss how to keep it as much as possible. Our first step is to create some pseudo-random number list: Just as a reminder, here is the definition of and See the result of: Yay! It ends! Beware though, it will only work if you always have something to put into a branch. For example will loop forever. Simply because it will try to access the head of Nonetheless, it is still a very cool example of what non strict programs have to offer. Left as an exercise to the reader: 04_Appendice/01_More_on_infinite_trees/10_Infinite_Trees.lhs 04_Appendice/01_More_on_infinite_trees/11_Infinite_Trees.lhs In order to resolve these problem we will modify slightly our A first problem, is the lack of infinite different number in our implementation of This shuffle function has the property (hopefully) not to have an upper nor lower bound. But having a better shuffle list isn’t enough not to enter an infinite loop. Generally, we cannot decide whether Any element of the left (resp. right) branch must all be strictly inferior (resp. superior) to the label of the root. Remark it will remains mostly an ordered binary tree. Furthermore, by construction, each node value is unique in the tree. Here is our new version of This new function Now run the program and be happy: You should realize the time to print each value is different. This is because Haskell compute each value when it needs it. And in this case, this is when asked to print it on the screen. Impressively enough, try to replace the depth from Left as an exercise to the reader: 04_Appendice/01_More_on_infinite_trees/11_Infinite_Trees.lhs Thanks to Particularly, I want to thank Emm a thousand times for the time he spent on correcting my English. Thank you man. Even if most recent languages try to hide them, they are present.↩ I know I’m cheating. But I will talk about non-strictness later.↩ For the brave, a more complete explanation of pattern matching can be found here.↩ Which is itself very similar to the javascript There are some unsafe exceptions to this rule. But you shouldn’t see such use in a real application except maybe for debugging purposes.↩ For the curious ones, the real type is Well, you’ll certainly need to practice a bit to get used to them and to understand when you can use them and create your own. But you already made a big step in this direction.↩ tl;dr: Few days ago there were about 20 job offer for Haskell. In only one day! How is that possible? As a real haskeller, I find this situation unbearable! After all, we must avoid success at all cost. And I’ll help SPJ achieve this honorable goal. Imagine a situation were you see people demonstrating some interest in learning Haskell. Quick! Prevent them from going further. If they come from the dynamic (uni-typed) languages like Python, Javascript…: Haskell? A statically typed language??? Hmm… You mean like C and Java? Such a remark should immediately shut down any interest in Haskell. If they want to produce application with them: Haskell? Isn’t it only a language for student! I don’t think it is useful for REAL WORLD applications! If they just want to learn something new: Haskell? Ah yes, I remember, mostly they only have the equivalent of Java interfaces and they stopped there. They don’t even have classes!!!! Can you imagine? I don’t even speak about class inheritance. We’re in 2016! And they don’t even support basic Object Oriented Programming. What a joke! If they love low level programming: Haskell? Ah yes, I heard that lazyness make it impossible to think about code complexity and generally cause lot of space leaks. And if it is not enough: Haskell? Ah yes. I’m not fan of their Stop the World GC. If they come from LISP and the statically typed language remark wasn’t enough. Try to mention the lack of macros in Haskell. Don’t mention template Haskell or even less Generics and all recent progress in GHC. Many hints there: The very first thing to do is to explain how Haskell is so easy to learn. How natural it is for everybody you know. And except someone you always considered very dumb, everybody was very productive in Haskell in few hours. Use vocabulary alien to them as much as possible. Here is a list of terms you should use in the very first minutes of your description of Haskell: Each of this term will hopefully be intimidating. Please don’t provide an obvious first example like: Instead prefer a fully servant example: This nice example should overflow the number of new concepts a Haskell newcomer should deal with: Of course use the most of your energy explaining the language extensions first. Use a great deal of details and if possible use as much as possible references to Category Theory. You’ll get bonus points if you mention HoTT! Double bonus points if you explain that understanding all details in HoTT is essential to use Haskell on a daily basis. Explain that what this does is incredible but for the wrong reasons. For example don’t mention why If you’re afraid that this example might be too close to a real world product, you can simply use some advanced lenses examples: Certainly a great example to start a new language with. If the the trends continue toward growth, then we might need to go further at the risk of breaking our own ecosystem: Yes we said, at all cost! So with all of this I believe we should be on the right track to avoid success at all cost! Sorry? What? Oh… Apparently I made a precedence mistake! SPJ didn’t asked to Sorry! My bad! Forget about all of this. Keep the good work everybody! Haskell is certainly one of the most awesome language in the world! Its community is also just great. I’m really happy to see it growth every year. Thanks to all contributors making it possible to still have a lot of fun after many years using Haskell! And the fact that in Haskell the right choice is preferred to the easiest choice, certainly helped. A good point to use more LISP syntax.↩ UPDATE: Nicholas Sterling had discovered a way to implement anonymous functions Thanks! With this last version you should use Example: tl;dr: some simple implementation of higher order function for zsh. Why is it important to have these functions? Simply because, the more I programmed with zsh the more I tended to work using functional programming style. The minimal to have better code are the functions Let’s compare. First a program which convert all gif to png in many different directories of different projects. Before ⇒ After ⇒ No more bloc! It might be a little bit harder to read if you’re not used to functional programming notation. But it is more concise and robusts. Another example with some tests. Find all files in project not containing an Before ⇒ After ⇒ Also, the first verstion is a bit easier to read. But the second one is clearly far superior in architecture. I don’t want to argue why here. Just believe me that the functional programming approach is superior. You can find an updated version of the code (thanks to Arash Rouhani). An older version is here thought. Here is the (first version) source code: tl;dr: Learn how to start a new Haskell project. Translate a starter tool written in “Good Sir Knight, will you come with me to Camelot, and join us at the Round Table?” In order to work properly with Haskell you need to initialize your environment. Typically, you need to use a cabal file, create some test for your code. Both, unit test and propositional testing (random and exhaustive up to a certain depth). You need to use In this article, we will create such an environment using a zsh script. Then we will write a Haskell project which does the same work as the zsh script. You will then see how to work in such an environment. If you are starting to understand Haskell but consider yourself a beginner, this tutorial will show you how to make a real application using quite surprisingly a lot of features: ☞ zsh is by its nature more suitable to file manipulation. But the Haskell code is clearly more organized while quite terse for a multi-purpose language. ☞ holy-project is on hackage. It can be installed with I recently read this excellent article: How to Start a New Haskell Project. While the article is very good, I lacked some minor informations1. Inspired by it, I created a simple script to initialize a new Haskell project. During the process I improved some things a bit. If you want to use this script, the steps are: What does this script do that Developing the script in In a first time, we initialize a new Haskell project with The different steps are: Features to note: So, apparently nothing too difficult to achieve. We should now have an initialized Haskell environment for us to work. The first thing you should do, is to go into this new directory and launch ‘./auto-update’ in some terminal. I personally use To print the introduction text in In the first Haskell version I don’t use colors. We see we can almost copy/paste. I just added the types. Now let’s just add the colors using the Edit Now look at the modified Haskell code: We could put this code in Make In order to ask questions, here is how we do it in shell script: If we want to abstract things a bit, the easiest way in shell is to use a global variable2 which will get the value of the user input like this: In Haskell we won’t need any global variable: Now our main function might look like: You could test it with We will see later how to guess the answer using the I don’t really like the ability to use capital letter in a package name. So in shell I transform the project name like this: In order to achieve the same result in Haskell (don’t forget to add the One important thing to note is that in zsh the transformation occurs on strings but in haskell we use list as intermediate representation: The module name is a capitalized version of the project name where we remove dashes. The haskell version is made by hand where zsh already had a capitalize operation on string with many words. Here is the difference between the shell and haskell way (note I splitted the effect of As the preceding example, in shell we work on strings while Haskell use temporary lists representations. Also I want to be quite restrictive on the kind of project name we can give. This is why I added a check function. Which verify the project name is not empty and use only letter, numbers and dashes: Making a project will consists in creating files and directories whose name and content depends on the answer we had until now. In shell, for each file to create, we used something like: In Haskell, while possible, we shouldn’t put the file content in the source code. We have a relatively easy way to include external file in a cabal package. This is what we will be using. Furthermore, we need a templating system to replace small part of the static file by computed values. For this task, I choose to use Cabal provides a way to add files which are not source files to a package. You simply have to add a Now we simply have to create our files at the specified path. Here is for example the first lines of the LICENSE file. It will be up to our program to replace the A first remark is for portability purpose we shouldn’t use String for file path. For example on Windows In order to use hastache we can either create a context manually or use generics to create a context from a record. This is the last option we will show here. So in a first time, we need to import some modules and declare a record containing all necessary informations to create our project. Once we have declared this, we should populate our Project record with the data provided by the user. So our main function should look like: Finally we could use hastache this way: We use external files in mustache format. We ask question to our user to fill a data structure. We use this data structure to create a context. Hastache use this context with the external files to create the project files. We need to initialize git and cabal. For this we simply call external command with the Our job is almost finished. Now, we only need to add some nice feature to make the application more enjoyable. The first one would be to add a better error message. And also update where this can be called We want to retrieve the We could note I changed the ask function slightly to take a maybe parameter. Concerning the parsing of We could notice, The task seems relatively easy, but we’ll see there will be some complexity hidden. Make a request on So the first problem to handle is to connect an URL. For this we will use the Generally, for simple request, we should use: But, after some research, I discovered we must declare an User-Agent in the HTTP header to be accepted by the github API. So we have to change the HTTP Header, and our code became slightly more complex: So now, we have a String containing a JSON representation. In javascript we would have used First we will need to add the It looks ugly, but it’s terse. In fact each function You can read this article on We now have all the feature provided by the original We will launch the API request sooner and in parallel to minimize our wait time: While it might feel a bit confusing, it is in fact quite simple. If you have a github account and had set correctly your We have a working product. But, I don’t consider our job finished. The code is about 335 lines. Considering that we: This is quite few. For short programs it is not obvious to split them into different modules. But my personal preference is to split it anyway. First we put all content of Of course you have to remember to rename the module of The One of the benefits in modularizing the code is that our main code is clearer. Some functions are declared only in a module and are not exported. This help us hide technical details. For example, the modification of the HTTP header to use the github API. We didn’t take much advantage of the project structure yet. A first thing is to generate some documentation. Before most function I added comment starting with Be sure to have And if you are at the root of your project you’ll get it. And now just launch: And magically, you’ll have a documentation in While the Haskell static typing is quite efficient to prevent entire classes of bugs, Haskell doesn’t discard the need to test to minimize the number of bugs. It is generally said to test we should use unit testing for code in IO and QuickCheck or SmallCheck for pure code. A unit test example on pure code is in the file Note So now, we could safely delete the directory You have to modify your cabal file. More precisely, you have to add So we have our example of unit testing using IO. We search the github nickname for some people I know and we verify github continue to give the same answer as expected. When it comes to pure code, a very good method is to use QuickCheck and SmallCheck. SmallCheck will verify all cases up to some depth about some property. While QuickCheck will verify some random cases. As this kind of verification of property is mostly doable on pure code, we will test the So don’t forget to declare Modify the The result is here: The test fail, but this is not an error. Our It is important to use Apparently, SmallCheck didn’t found any counter example. I don’t know how it generates Strings and using deeper search is really long. Congratulation! Now you could start programming in Haskell and publish your own cabal package. For example, you have to install the test libraries manually to use There is no easy way to do something like Having a good level of power in templates is very difficult. imho Mustache has made the best compromise.↩ tl;dr: You want to teach yourself vim (the best text editor known to human kind) in the fastest way possible. This is my way of doing it. You start by learning the minimal to survive, then you integrate all the tricks slowly. Vim the Six Billion Dollar editor Better, Stronger, Faster. Learn vim and it will be your last text editor. There isn’t any better text editor that I know of. It is hard to learn, but incredible to use. I suggest you teach yourself Vim in 4 steps: By the end of this journey, you’ll become a vim superstar. But before we start, just a warning. Learning vim will be painful at first. It will take time. It will be a lot like playing a musical instrument. Don’t expect to be more efficient with vim than with another editor in less than 3 days. In fact it will certainly take 2 weeks instead of 3 days. In a standard editor, typing on the keyboard is enough to write something and see it on the screen. Not this time. Vim is in Normal mode. Let’s go to Insert mode. Type the letter You should feel a bit better. You can type letters like in a standard editor. To get back to Normal mode just press the You now know how to switch between Insert and Normal mode. And now, here are the commands that you need in order to survive in Normal mode: Recommended: Only 5 commands. That is all you need to get started. Once these command start to become natural (maybe after a day or so), you should move on to level 2. But first, just a little remark about Normal mode. In standard editors, to copy you have to use the A last word about notations: You know the commands required for survival. It’s time to learn a few more commands. These are my suggestions: Insert mode variations: Basic moves Copy/Paste Undo/Redo Load/Save/Quit/Change File (Buffer) Take the time to learn all of these command. Once done, you should be able to do every thing you are able to do in other editors. You may still feel a bit awkward. But follow me to the next level and you’ll see why vim is worth the extra work. Congratulation for reaching this far! Now we can start with the interesting stuff. At level 3, we’ll only talk about commands which are compatible with the old vi editor. Let’s look at how vim could help you to repeat yourself: Some examples, open a file and type: Knowing how to move efficiently with vim is very important. Don’t skip this section. Word moves: By default, words are composed of letters and the underscore character. Let’s call a WORD a group of letter separated by blank characters. If you want to consider WORDS, then just use uppercase characters: Now let’s talk about very efficient moves: Believe me, the last three commands are gold. Remember about the importance of vi moves? Here is the reason. Most commands can be used using the following general format: For example : We also can do things like But what was true for With all preceding commands you should be comfortable using vim. But now, here are the killer features. Some of these features were the reason I started to use vim. A useful tip is: These command can only be used after an operator in visual mode. But they are very powerful. Their main pattern is: Where action can be any action, for example, Suppose the cursor is on the first Rectangular blocks are very useful for commenting many lines of code. Typically: Note: in Windows you might have to use In Insert mode, just type the start of a word, then type Example On a line containing only the number 1, type this: We saw an example with Add something at the end of all visually selected lines: These are the most important commands, but you should look at That was 90% of the commands I use every day. I suggest that you learn no more than one or two new commands per day. After two to three weeks you’ll start to feel the power of vim in your hands. Learning Vim is more a matter of training than plain memorization. Fortunately vim comes with some very good tools and excellent documentation. Run vimtutor until you are familiar with most basic commands. Also, you should read this page carefully: Then, you will learn about If you liked this article, there is a follow up: Vim as IDE tl;dr: Short introduction to Parsec for beginner.
+From String:
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+To data structure:
+
+ tl;dr: How I manage safely my password with success for some years now. Disclamer, this is an unashamed attempt to make you download my iPhone app ;-). You’re always here? Even if you won’t download my app, you should read more. My method doesn’t necessitate my app. It is both safe and easy to use everyday. If you just want to use the tools without searching to understand why it is safe, just jump at the end of this article by clicking here. Even paranoid could have ennemies. Imagine you find a really good password. You use it on GMail, Amazon, PayPal, Twitter, Facebook… One day you see a nice online game you want to try. They ask you your email and a password. Some week passes, and the host machine of this online game is hacked. Your mail and password is now in bad hands. Unfortunately for you, you use the same password everywhere. Then, the attacker can simply try your password everywhere. On PayPal for example. Well now, how could we fix that? the good, the bad & the ugly The mostly used method is to remember a subset of different passwords. In the best cases, your remember about 13 password. Some strong, some weak. What to do if you use more online services than your memory can handle? A bad solution would be to chose passwords like this: Unfortunately, if someone get your password on badonlinegame, he could easily find your other passwords. Of course you can imagine some better transformation. But it is hard to find a very good one. Fortunately, there exists functions which handle exactly this problem. Hash Function. Knowing the result of a hash function, it is difficult to know what was their input. For example: If someone has Let choose SHA1 as hash function. Now the password for any website should of the form: Where: But what about some website constraint? For example regarding the length of the password? What to do if you want to change your password? What to do if you want number or special characters? This is why, for each website I need some other parameters: Depending on my situation here are the tools I made & use: My password are at a copy/paste on all environment I use. I have some services for which I have password of 40 characters. Now I use 10 character for most of my passwords. Further more using shorter password make it even harder for an attaquer to retrieve my master password. I would be happy to hear your thoughts on using this methodology. tl;dr: Determine with the most objectivity possible the best(s) web framework(s) depending on your needs. Here are the results. Please note the actual ability to take a rational decision is pretty bad for now. This is it. It sounds easy! You just need to choose a good modern web framework, when suddenly: After your brain stack overflowed, you decide to use a very simple methodology. Answer two questions: Which language am I familiar with? Great! This is it. But, you continually hear this little voice. “You didn’t made a bad choice, yes. But … This article try to determine in the most objective and rational way the best(s) web framework(s) depending on your needs. To reach this goal, I will provide a decision tool in the result section. I will use the following methodology: Methodology ☞ Important Note This is why I made a very flexible decision tool: Here are the important features (properties/parameters) I selected to make the choice: Each feature is quite important and mostly independant from each other. I tried to embrace most important topics concerning web frameworks with these four properties. I am fully concious some people might lack another important feature. Nonetheless the methodology used here can be easily replicated. If you lack an important property add it at will and use this choice method. Also each feature is very hard to measure with precision. This is why we will only focus on order of magnitude. For each property a framework could have one of the six possible values: Excellent, Very Good, Good, Medium, Bad or Very Bad So how to make a decision model from these informations? One of the most versatile method is to give a weight for each cluster value. And to select the framework maximizing this score: For example: Using this weighted table, that means: So for each framework we compute its score relatively to a weighted table. And we select the best(s). Example: Using this hypothetic framework and the preceeding table. Most needs should be expressed by such a weighted table. In the result section, we will discuss this further. It is now time to try to get these measures. None of the four properties I choosen can be measured with perfect precision. But we could get the order of magnitude for each. I tried to focus on the framework only. But it is often easier to start by studying the language first. For example, I have datas about popularity by language and I also have different datas concerning popularity by framework. Even if I use only the framework focused datas in my final decision model, it seemed important to me to discuss about the datas for the languages. The goal is to provide a tool to help decision not to give a decision for you. RedMonk Programming Language Rankings (January 2013) provide an apparent good measure of popularity. While not perfect the current measure feel mostly right. They create an image using stack overflow and github data. Vertical correspond to the number of questions on stackoverflow. Horizontal correspond to the number of projects on github. If you look at the image, your eye can see about four clusters. The 1st cluster correspond to mainstream languages: Most developer know at least one of these language. The second cluster is quite bigger. It seems to correspond to languages with a solid community behind them. I don’t get into detail, but you could also see third and fourth tier popular languages. So: Mainstream: JavaScript, Java, PHP, Python, Ruby, Good: Scala, Haskell, Visual Basic, Assembly, R, Matlab, ASP, ActionScript, Coffeescript, Groovy, Clojure, Lua, Prolog Medium: Erlang, Go, Delphi, D, Racket, Scheme, ColdFusion, F#, FORTRAN, Arduino, Tcl, Ocaml Bad: third tier Very Bad: fourth tier I don’t thing I could find easily web frameworks for third or fourth tier languages. For now, I only talked about language popularity. But what about framework popularity? I made a test using number of question on stackoverflow only. Then by dividing by two for each 6 cluster: As we can see, our framework popularity indicator can be quite different from its language popularity. For now I didn’t found a nice way to merge the results from RedMonk with these one. So I’ll use these unperfect one. Hopefully the order of magninute is mostly correct for most framework. Another objective measure is efficiency. We all know benchmarks are all flawed. But they are the only indicators concerning efficiency we have. I used the benchmark from benchmarksgame. Mainly, there are five clusters: Remarks concerning some very slow languages: This is a first approach. The speed of the language for basic benchmarks. But, here we are interrested in web programming. Fortunately techempower has made some tests focused on most web frameworks: These benchmark doesn’t fit well with our needs. The values are certainly quite imprecise to your real usage. The goal is just to get an order of magnitude for each framework. Another problem is the high number of informations. As always, we should remember these informations are also imprecise. So I simply made some classes of efficiency. Remark: I separated the clusters by using power of 2 relatively to the fastest. These are manually made clusters. But you get the idea. Certainly, some framework could jump between two different clusters. So this is something to remember. But as always, the order of magnitude is certainly mostly right. Now, how to objectively measure expressiveness? RedMonk had a very good idea to find an objective (while imprecise) measure of each language expressiveness. Read this article for details. After filtering languages suitable for web development, we end up with some clusters: Unfortunately there is no information about dart. So I simply give a very fast look at the syntax. As it looked a lot like javascript and js is quite low. I decided to put it close to java. Also an important remark, javascript score very badly here while coffeescript (compiling to js) score “excellent”. So if you intend to use a javascript framework but only with coffescript that should change substantially the score. As I don’t believe it is the standard. Javascript oriented framework score very badly regarding expressiveness. I couldn’t find any complete study to give the number of bug relatively to each framework/language. But one thing I saw from experience is the more powerful the type system the safest your application is. While the type system doesn’t remove completely the need to test your application a very good type system tend to remove complete classes of bug. Typically, not using pointer help to reduce the number of bugs due to bad references. Also, using a garbage collector, reduce greatly the probability to access unallocated space. From my point of view, robustness is mostly identical to safety. Here are the clusters: So applying this to frameworks gives the following clusters: For the result I initialized the table with my own needs. And I am quite happy it confirms my current choice. I sware I didn’t given yesod any bonus point. I tried to be the most objective and factual as possible. Now, it is up to you to enter your preferences. On each line you could change how important a feature is for you. From essential to unsignificant. Of course you could change the matrix at will. I just show a top 10 frameworks. In order to give a more understandable measure I provide the log of the score. I didn’t had the courage in explaining in what the scoring system is good. Mostly, if you use product instead of sum for the score you could use power of e for the values in the matrix. And you could see the matrix as a probability matrix (each line sum to 1). Which provide a slighly better intuition on whats going on. Remember only that values are exponential. Do not double an already big value for example the effect would be extreme. All of this is based as most as I could on objective data. The choice method seems both rather rational and classical. It is now up to you to edit the score matrix to set your needs. I know that in the current state there are many flaws. But it is a first system to help make a choice rationally. I encourage you to go further if you are not satisfied by my method. The source code for the matrix shouldn’t be too hard to read. Just read the source of this webpage. You could change the positionning of some frameworks if you believe I made some mistake by placing them in some bad clusters. So I hope this tool will help you in making your life easier. tl;dr: How to use m4 to increase the power of deficient languages. Two examples: improve xslt syntax and make fractal with svg. xml was a very nice idea about structuring data. Some people where so enthusiastic about xml they saw it everywhere. The idea was: the future is xml. Then some believed it would be a good idea to invent many xml compatible format and even programming languages with xml syntax. Happy! Happy! Joy! Joy! Unfortunately, xml was made to transfert structured data. Not a format a human should see or edit directly. The sad reality is xml syntax is simply verbose and ugly. Most of the time it shouldn’t be a problem, as nobody should see it. In a perfect nice world, we should never deal directly with xml but only use software which deal with it for us. Guess what? Our world isn’t perfect. Too sad, a bunch of developer have to deal directly with this ugly xml. Unfortunately xml isn’t the only case of misused format I know. You have many format for which it would be very nice to add variables, loops, functions… If like me you hate with passion xslt or writing xml, I will show you how you could deal with this bad format or language. Let’s start by the worst case of misused xml I know: xslt. Any developer who had to deal with xslt know how horrible it is. In order to reduce the verbosity of such a bad languages, there is a way. Here are some example: Now just compile this file: Profit! Now svg is an xml format used to represent vector graphics, it even support animations. At its beginning some people believed it would be the new Flash. Apparently, it will be more canvas + js. Let me show you the result: Click to view directly the svg. It might slow down your computers if you have an old one. The positionning of the “esod” text with regards to the reversed “λ” was done by changing position in firebug. I didn’t had to manually regenerate to test. Making such a fractal is mostly: If I had to do this for each step, I had make a lot of copy/paste in my svg, because the transformation is always the same, but I cannot say, use transformation named “titi”. Then instead of manually copying some xml, I used m4 and here is the commented code: and I compiled it to The main λ is duplicated 3 times. Each transformation is named by: Each transformation is just a similarity (translate + rotation + scale). Once fixed, we should now simply copy and repeat for each new level. Now it is time to talk about where the magic occurs: At the final 5th level there is 35=243 λ. All level combined have 36-1 / 2 = 364 λ. I could preview the final result easily. Without the macro system, I would have to make 5 copy/paste + modifications for each try. It was fun to make a fractal in Another usage I thouhgt about is to use m4 to organize languages such as brainfuck. tl;dr: Install Haskell (OS X and Linux only) by pasting the following in your terminal: update (28 march 2015): I now use Haskell LTS instead of a random stackage version. If you are on windows, just download the Haskell Platform and follow the instruction to use Haskell LTS. If you want to know the why and the how; you should read the entire article. The main weakness of Haskell as nothing to do with the language itself but with its ecosystem1. The main problem I’ll try to address is the one known as cabal hell. The community is really active in fixing the issue. I am very confident that in less than a year this problem will be one of the past. But to work today, I provide an install method that should reduce greatly two effects of cabal hell: With my actual installation method, you should minimize your headache and almost never hit a dependency error. But there could exists some. If you encounter any dependency error, ask gently to the package manager to port its package to stackage. So to install copy/paste the following three lines in your terminal: You can read the script and you will see that this is quite straightforward. As the version of libraries is fixed up until you update the Haskell LTS version, you should never use cabal sandbox. That way, you will only compile each needed library once. The compiled objects/binaries will be in your This script use the latest Haskell LTS. So if you use this script at different dates, the Haskell LTS might have changed. While it comes to cabal hell, some solutions are sandboxes and From my point of view, Haskell LTS is the best step in the right direction. The actual cabal hell problem is more a human problem than a tool problem. This is a bias in most programmer to prefer resolve social issues using tools. There is nothing wrong with hackage and cabal. But for a package manager to work in a static typing language as Haskell, packages must work all together. This is a great strength of static typed languages that they ensure that a big part of the API between packages are compatible. But this make the job of package managing far more difficult than in dynamic languages. People tend not to respect the rules in package numbering2. They break their API all the time. So we need a way to organize all of that. And this is precisely what Haskell LTS provide. A set of stable packages working all together. So if a developer break its API, it won’t work anymore in stackage. And whether the developer fix its package or all other packages upgrade their usage. During this time, Haskell LTS end-users will be able to develop without dependency issues.
+The image of the cat about to jump that I slightly edited can found here
+ By ecosystem of a language I mean, the community, the tools, the documentations, the deployment environments, the businesses using the language, etc… Mainly everything that has nothing to do with the detail of a programming language but has to do on how and why we use it.↩ I myself am guilty of such behavior. It was a beginner error.↩ tl;dr: Default share buttons track your users, aren’t uniform with your design, use computer ressources and slow down your web page loading. Do it right. Use static links instead. If you don’t want to read, just copy/paste this in your html: Ever been on a website and want to tweet about it? Fortunately, the website might have a button to help you. But do you really know what this button do? The “Like”, “Tweet” and “+1” buttons will call a javascript. It will get access to your cookies. It helps the provider of the button to know who you are. In plain English, the “+1” button will inform Google you are visiting the website, even if you don’t click on “+1”. The same is true for the “like” button for facebook and the “tweet this” button for twitter. The problem is not only a privacy issue. In fact (sadly imho) this isn’t an issue for most people. These button consume computer ressources. Far more than a simple link. It thus slow down a bit the computer and consume energy. These button could also slow down the rendering of your web page. Another aspect is their design. Their look and feel is mostly imposed by the provider. The most problematic aspect in my opinion is to use a third party js on your website. What if tomorrow twitter update their tweet button? If the upgrade break something for only a minority of people, they won’t fix it. This could occur anytime without any notification. They just have to add a Using social network buttons: I will provide you two solutions with the following properties: Solution 1 (no js): But you have to replace Solution 2 (Just copy/paste): If you don’t want to write the url yourself, you could use some minimal js: Here is the result: If you don’t want just text but nice icons. You have many choices: As the first solution is pretty straightforward, I’ll explain the second one. Now add this to your html: Solution 1 (without js): Solution 2 (same with a bit more js): Here is the result: ps: On my personal website I continue to use Google analytics. Therefore, Google (and only Google, not facebook nor twitter) can track you here. But I might change this in the future. tl;dr: Web typography sucks and we’ll have to wait forever before it will be fixed. I stumbled upon open typography. Their main message is: «There is no reason to wait for browser development to catch up. We can all create better web typography ourselves, today.» As somebody who tried to make my website using some nice typography features and in particular ligatures, I believe this is wrong. I already made an automatic system which will detect and replace text by their ligatures in my blog. But this I never published this on the web and this is why. First, what is a ligatures? What is the problem between the Web and ligatures? The first one is: you cannot search them. For example, try to search the word “first”: The second one is the rendering, for example, try to use a ligature character with small caps: Here is a screenshot of what I see: The browser isn’t able to understand that the ligature character “fi” should render as This way, how could you use a ligature Unicode character on a site on which you could change the css? Let’s compare to LaTeX. If you take attention to detail, you’ll see the first “first” contains a ligature. Of course the second render nicely. The code I used were: LaTeX was intelligent enough to create himself the ligatures when needed. The “st” ligature is rare and not rendered in LaTeX by default. But if you want you could also render rare ligature using XƎLaTeX: I took this image from the excellent article of Dario Taraborelli. Clearly fix the rendering of ligature in a browser is a difficult task. Simply imagine the number of strange little exceptions: Nonetheless if someone has a solution, I would be happy to hear about it. In fact, you might see a ligature and the search works because I now use some CSS ninja skills: tl;dr: How to use vim as a very efficient IDE In Learn Vim Progressively I’ve show how Vim is great for editing text, and navigating in the same file (buffer). In this short article you’ll see how I use Vim as an IDE. Mainly by using some great plugins. There are a lot of Vim plugins. To manage them I use To install it: ☞ Note I have two parts in my Before anything, you should protect your eyes using a readable and low contrast colorscheme. For this I use solarized dark. To add it, you only have to write this in your You should be able to see and destroy trailing whitespaces. You can clean trailing whitespace with And also you should see your 80th column. One of the most important hidden skills in programming is the ability to search and find files in your projects. The majority of people use something like I switched to unite. No left column lost. Faster to find files. Mainly it works like Spotlight on OS X. First install Now type space twice. A list of files appears. Start to type some letters of the file you are searching for. Select it, type return and bingo the file opens in a new horizontal split. If something goes wrong just type Now you are able to search file by name easily and efficiently. Now search text in many files. For this you use Don’t forget to add a space after the These are two of the most powerful shortcut for working in a project. using So what If you type So with this you should already be able to navigate between files very easily. Show which line changed since your last commit. And the “defacto” git plugin: You can reset your changes from the latest git commit with Just select and type If you want to align the second column, Vim has a basic auto completion system. The shortcuts are My current Haskell programming environment is great! Each time I save a file, I get a comment pointing to my errors or proposing me how to improve my code. So here we go: ☞ Don’t forget to install Just enjoy! I use My main language at work is Clojure. And my current vim environment is quite good. I lack the automatic integration to So mainly you’ll have real rainbow-parenthesis (the default values are broken for solarized). I used the vim Working with Clojure will becomre quite smoother. You can eval any part of your code, you must launch a Clojure REPL manually in another terminal thought. I hope it will be useful. Last but not least, if you want to use my vim configuration you can get it here: tl;dr: Yesod is a framework which has recently matured to the point where you should consider using it. Before telling you why you should learn Haskell and use Yesod, I will illustrate the many features Yesod introduces which are missing in other frameworks. Let’s start by an obligatory link from xkcd: When you create a web application, a lot of time is spent dealing with strings. Strings for URL, HTML, JavaScript, CSS, SQL, etc… To prevent malicious usage you have to protect each strings to be sure, no script will pass from one point to another. Suppose a user enter this user name: You must transform each Yesod does its best to handle cross scripting issues. Both between the client and the server and between the server and your DB. Here is an example: As Yesod’s widgets are different from javascript widget. For yesod, widgets are sets of small parts of a web application. If you want to use many widgets in a same page yesod do the work. Some examples of widget are: For each of this part, you might need, Some in the header, some in the body. You can declare a widget as this (note I use a very high meta-language): The real syntax is: Note the awesome Shakespearean inspired name convention. Another good reason to use yesod. And when your page render, yesod makes it easy to render everything nicely: Furthermore, if you use say 10 widgets each with a bit of CSS, yesod will create a unique and compressed CSS file. Except if you expressed a need to change the header by using different CSS. This is just awesome! In standard routing system you have for each entry a couple: regexp → handler The only way to discover the right rules is to match each regexp to the current URL. Then you can see behaviour such as, if you change the order of the rules you can lose or win time. On the other hand yesod compiles the routes. Therefore it can optimize it. Of course two routes must not interfere. is invalid by default (you can make it valid, but I don’t think it is a good idea). You’d better and test if If you are a haskeller, I believe you shouldn’t fear the special syntax imposed by the standard yesod way of doing things. Just try it more than the firsts basic tutorials. Until here I believe it goes in the right direction. Even if I believe the real future is by generating HTML pages from the client (using javascript) and server limited to serve JSON (or XML, or any object representation system). To conclude, Yesod is awesome. Just overcome the difficulties about learning a bit of haskell and try it! There are no articles in the blog
+$else
+ -- Show the list of articles
+
+
+
+
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+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ How to repair a cutted XML?
+ and how to do it without any parsor?
+
+
+
+
+
+
+
+<div class="corps">
+ <div class="intro">
+ <p>Introduction</p>
+ </div>
+ <p>The first paragraph</p>
+ <img src="/img/img.png" alt="an image"/>
+ <p>Another long paragraph</p>
+</div>
+<div class="corps">
+ <div class="intro">
+ <p>Introduction</p>
+ </div>
+ <p>The first paragraph</p>
+ <img src="/img/im<img> tag.div for class corps and the XML is repaired. Of course, when you cut inside a tag, you sould go back, as if you where just before it. Delete this tag and all is ok.
+[]
+[div] <div class="corps">
+[div, div] <div class="intro">
+[div, div, p] <p>
+ Introduction
+[div, div] </p>
+[div] </div>
+[div, p] <p>
+ The first paragraph
+[div] </p>
+[div] <img src="/img/img.png" alt="an image"/>
+[div, p] <p>
+ Another long paragraph
+[div] </p>
+[] </div>res contain the repaired XML.xml variable contain the cutted XML.
+# repair cutted XML code by closing the tags
+# work even if the XML is cut into a tag.
+# example:
+# transform '<div> <span> toto </span> <p> hello <a href="http://tur'
+# into '<div> <span> toto </span> <p> hello </p></div>'
+def repair_xml( xml )
+ parents=[]
+ depth=0
+ xml.scan( %r{<(/?)(\w*)[^>]*(/?)>} ).each do |m|
+ if m[2] == "/"
+ next
+ end
+ if m[0] == ""
+ parents[depth]=m[1]
+ depth+=1
+ else
+ depth-=1
+ end
+ end
+ res=xml.sub(/<[^>]*$/m,'')
+ depth-=1
+ depth.downto(0).each { |x| res<<= %{</#{parents[x]}>} }
+ res
+end
+
+
+
+
+
+
+
+ Published on 2010-05-19
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
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+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Trees; Pragmatism and Formalism
+ When theory is more efficient than practice
+
+
+
+
+
+
+
+
+
+
+Abstract (longer than tl;dr: )
+
+
+
+– OK, now that should just work.
+– Yeah!!!
+– Oops! I forgotten that…
+repeat until death
+First: my experience
+
+<rubrique>
+ <contenu>
+ <tag1>value1</tag1>
+ <tag2>value2</tag2>
+ ...
+ </contenu>
+ <enfant>
+ <rubrique>
+ ...
+ </rubrique>
+ ...
+ <rubrique>
+ ...
+ </rubrique>
+ </enfant>
+</menu>
+<item name="Menu0">
+ <value>
+ <item name="menu">
+ <value>
+ <item name="tag1">
+ <value>value1</value>
+ </item>
+ <item name="tag2">
+ <value>value2</value>
+ </item>
+ ...
+ <item name="menu">
+ <value>
+ ...
+ </value>
+ <value>
+ ...
+ </value>
+ </item>
+ </value>
+ </item>
+ </value>
+</item>
+
+
+
+
+
+
+Let’s begin to write codeThink
+<item name="Menu"> by simpler name M for example. I obtained something like:
+
+
+r - x - a
+ \ \
+ \ b
+ y - c
+
+x node, you obtain
+ a
+ /
+r - b
+ \
+ y - c
+
+
+<r>
+ <x>
+ <a>value for a</a>
+ <b>value for b</b>
+ </x>
+ <y>
+ <c>value for c</c>
+ </y>
+</r>x nodes is equivalent to pass the Solution
+
+R - C - tag1
+ \ \
+ \ tag2
+ E -- R - C - tag1
+ \ \ \
+ \ \ tag2
+ \ E ...
+ R - C - tag1
+ \ \
+ \ tag2
+ E ...
+
+
+ tag1
+ /
+M - V - M - V - tag2 tag1
+ \ /
+ M --- V - tag2
+ \ \
+ \ M
+ \ tag1
+ \ /
+ V - tag2
+ \
+ M
+
+
+
+
+E -> M
+R -> V
+s%</?contenu>%%g
+s%<enfant>%<item name="menu">%g
+s%</enfant>%</item>%g
+s%<rubrique>%<value>%g
+s%</rubrique>%</value>%gConclusion
+
+
+
+
+
+
+
+
+
+
+ Published on 2010-05-24
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2010-06-15-Get-my-blog-engine/index.html b/src/Scratch/en/blog/2010-06-15-Get-my-blog-engine/index.html
new file mode 100644
index 0000000..a6684ea
--- /dev/null
+++ b/src/Scratch/en/blog/2010-06-15-Get-my-blog-engine/index.html
@@ -0,0 +1,166 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ multi language choices
+
+
+
+
+
+
+
+Bonjour,
+
+voici un exemple de texte en français.
+[image](url)
+
+
+Hello,
+
+here is an example of english text.
+[image](url)
+
+
+ fr: Bonjour,
+ en: Hello,
+
+ en: here is an example of english text.
+ fr: voici un exemple de texte en français.
+[image](url)
+
+fr: or en: at some line’s beginning using the useful C-v. However nanoc was conceived to be used for one language only. Or to be used with the first method. I tried to adapt nanoc to my usage. But after a while, I found it easier to pre-filter the nanoc work by a simple script. My script transform my file into two new files. And all work like a charm.
+
+
+
+
+
+
+
+ Published on 2010-06-14
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2010-06-17-hide-yourself-to-analytics/code/become_hidden.html b/src/Scratch/en/blog/2010-06-17-hide-yourself-to-analytics/code/become_hidden.html
new file mode 100644
index 0000000..946d873
--- /dev/null
+++ b/src/Scratch/en/blog/2010-06-17-hide-yourself-to-analytics/code/become_hidden.html
@@ -0,0 +1,20 @@
+
+
+
+
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Get my blog engine
+
+
+
+
+
+
+
+
+
+Main Documentation Page
+Use It NOW!
+
+$ cd /root/of/nanoc3_blog
+$ ./task/new_blog_entry Title of the blog
+$ vi latest.md
+$ ./task/recompileoutput directory.
+Documentation
+Useful things to know
+Multi-language
+multi are processed and copied in the content directory. For each file in multi, each line starting by ‘fr:’ are copied (without the fr: into the content/html/fr/ tree, but not into the content/html/en tree. File not starting by fr: or en: are copied in each destinations.tasks/config, and config.yaml, create a content/html/xx where xx is the language code.Edition & Rendering
+additional keywords
+n``ewcorps directive (see examples).b``egindiv(classname), e``nddiv. (See some existing blog entries for example). Use the class intro for the abstract part.<``desc> (See source code for example).Typography
+ . This enable not to have a line starting by a single special character.<sc> tags.
+
+(c``) is replaced by (c).(r``) is replaced by (r).<``- is replaced by <-.-``> is replaced by ->.source code
+file attribute is not required.blog
+
+multi/blog/2010-06-01-the-title.md
+multi/blog/2010-06-01-the-title/second_part.md
+multi/blog/2010-06-01-the-title/third_part.md
+
+mobileme
+output/Scratch directory. This was made like that to work nicely with iWeb organisation of websites.menu
+menupriority meta-data in the header of the files.isHidden: true in the header.Details
+
+
+
+
+
+
+
+
+ Published on 2010-06-15
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2010-06-17-track-events-with-google-analytics/code/yga.js b/src/Scratch/en/blog/2010-06-17-track-events-with-google-analytics/code/yga.js
new file mode 100644
index 0000000..99f4a46
--- /dev/null
+++ b/src/Scratch/en/blog/2010-06-17-track-events-with-google-analytics/code/yga.js
@@ -0,0 +1,45 @@
+$(document).ready( function() {
+ // add an event to all link for google analytics
+ $('a').click(function () {
+ // tell analytics to save event
+ try {
+ var identifier=$(this).attr('id') ;
+ var href=$(this).attr('href')
+ var label="";
+ if ( typeof( identifier ) != 'undefined' ) {
+ label=label+'[id]:'+identifier
+ category='JSLink'
+ }
+ if ( typeof( href ) != 'undefined' ) {
+ label=label+' [href]:'+href
+ if ( href[0] == '#' ) {
+ category='Anchor';
+ } else {
+ category='Link';
+ }
+ }
+ _gaq.push(['_trackEvent', category, 'clicked', label]);
+ // console.log('[tracked]: ' + category + ' ; clicked ; ' + label );
+ }
+ catch (err) {
+ console.log(err);
+ }
+
+ // pause to allow google script to run
+ var date = new Date();
+ var curDate = null;
+ do {
+ curDate = new Date();
+ } while(curDate-date < 300);
+ });
+});
+
+var _gaq = _gaq || [];
+_gaq.push(['_setAccount', 'UA-XXXXXXXX-1']);
+_gaq.push(['_trackPageview']);
+
+(function() {
+ var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
+ ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
+ var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);
+ })();
diff --git a/src/Scratch/en/blog/2010-06-17-track-events-with-google-analytics/index.html b/src/Scratch/en/blog/2010-06-17-track-events-with-google-analytics/index.html
new file mode 100644
index 0000000..2cf3e51
--- /dev/null
+++ b/src/Scratch/en/blog/2010-06-17-track-events-with-google-analytics/index.html
@@ -0,0 +1,162 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Hide Yourself to your Analytics
+
+
+
+
+
+
+ jquery-cookie.admin is not set in the cookie before adding the visit.
+ var admin = $.cookie('admin');
+ if (! admin) {
+ // put your analytics code here
+ } else {
+ console.log("[WARNING] you're HIDDEN to analytics");
+ }
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+ "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml" lang="fr" xml:lang="fr">
+ <head>
+ <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
+ <script type="text/javascript" src="jquery.js"></script>
+ <script type="text/javascript" src="jquery.cookie.js"></script>
+ <script>
+ $(document).ready(function(){
+ $.cookie('admin',1);
+ $('#info').html('Analytics can no more see you.')
+ });
+ </script>
+ <title>Hide to analytics</title>
+ </head>
+ <body>
+ <div id="info"></div>
+ </body>
+</html>
+<?xml version="1.0" encoding="utf-8"?>
+<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
+ "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
+<html xmlns="http://www.w3.org/1999/xhtml" lang="fr" xml:lang="fr">
+ <head>
+ <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
+ <script type="text/javascript" src="jquery.js"></script>
+ <script type="text/javascript" src="jquery.cookie.js"></script>
+ <script>
+ $(document).ready(function(){
+ $.cookie('admin',null);
+ $('#info').html('Analytics can see you.')
+ });
+ </script>
+ <title>Hide to analytics</title>
+ </head>
+ <body>
+ <div id="info"></div>
+ </body>
+</html>
+
+
+
+
+
+
+
+ Published on 2010-06-17
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2010-06-19-jQuery-popup-the-easy-way/code/essai.js b/src/Scratch/en/blog/2010-06-19-jQuery-popup-the-easy-way/code/essai.js
new file mode 100644
index 0000000..d0c8361
--- /dev/null
+++ b/src/Scratch/en/blog/2010-06-19-jQuery-popup-the-easy-way/code/essai.js
@@ -0,0 +1,22 @@
+// --- code popup ---
+function openPopup() {
+ $(this).clone(false).appendTo($("#_code"));
+ $("#_code").show();
+}
+
+function closePopup() {
+ $("#_code").html("");
+ $("#_code").hide();
+}
+
+function initCode() {
+ $(".code").click(openPopup);
+ $(".code").css({cursor: "pointer"});
+ $('body').append('');
+ $('#_code').css( { 'text-align': "justify", position: "fixed",
+ left:0, top:0, width: "100%", height: "100%",
+ "background-color": "rgba(0, 0, 0, 0.8)", 'z-index':2000, 'padding':'3px'} );
+ $('#_code').hide();
+ $('#_code').click(closePopup);
+}
+// --- end of code popup section ---
diff --git a/src/Scratch/en/blog/2010-06-19-jQuery-popup-the-easy-way/index.html b/src/Scratch/en/blog/2010-06-19-jQuery-popup-the-easy-way/index.html
new file mode 100644
index 0000000..f70f95f
--- /dev/null
+++ b/src/Scratch/en/blog/2010-06-19-jQuery-popup-the-easy-way/index.html
@@ -0,0 +1,131 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Track Events with Google Analytics
+ Asynchronous Complete Google Analytics with jQuery
+
+
+
+
+
+
+ yga.js:
+ <script type="text/javascript" src="jquery.js"></script>
+ <script type="text/javascript" src="yga.js"></script>yga.js file:
+$(document).ready( function() {
+ // add an event to all link for google analytics
+ $('a').click(function () {
+ // tell analytics to save event
+ try {
+ var identifier=$(this).attr('id') ;
+ var href=$(this).attr('href')
+ var label="";
+ if ( typeof( identifier ) != 'undefined' ) {
+ label=label+'[id]:'+identifier
+ category='JSLink'
+ }
+ if ( typeof( href ) != 'undefined' ) {
+ label=label+' [href]:'+href
+ if ( href[0] == '#' ) {
+ category='Anchor';
+ } else {
+ category='Link';
+ }
+ }
+ _gaq.push(['_trackEvent', category, 'clicked', label]);
+ // console.log('[tracked]: ' + category + ' ; clicked ; ' + label );
+ }
+ catch (err) {
+ console.log(err);
+ }
+
+ // pause to allow google script to run
+ var date = new Date();
+ var curDate = null;
+ do {
+ curDate = new Date();
+ } while(curDate-date < 300);
+ });
+});
+
+var _gaq = _gaq || [];
+_gaq.push(['_setAccount', 'UA-XXXXXXXX-1']);
+_gaq.push(['_trackPageview']);
+
+(function() {
+ var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true;
+ ga.src = ('https:' == document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js';
+ var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s);
+ })();UA-XXXXXXXX-1 by your google analytics code and you’re done.Content and Event Tracking as shown in the following screenshot:
+
+
+
+
+
+
+
+
+
+
+ Published on 2010-06-17
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2010-07-05-Cappuccino-and-Web-applications/index.html b/src/Scratch/en/blog/2010-07-05-Cappuccino-and-Web-applications/index.html
new file mode 100644
index 0000000..47996a7
--- /dev/null
+++ b/src/Scratch/en/blog/2010-07-05-Cappuccino-and-Web-applications/index.html
@@ -0,0 +1,190 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ jQuery popup the easy way
+
+
+
+
+
+
+
+// --- code popup ---
+function openPopup() {
+ $(this).clone(false).appendTo($("#_code"));
+ $("#_code").show();
+}
+
+function closePopup() {
+ $("#_code").html("");
+ $("#_code").hide();
+}
+
+function initCode() {
+ $(".code").click(openPopup);
+ $(".code").css({cursor: "pointer"});
+ $('body').append('<div id="_code"></div>');
+ $('#_code').css( { 'text-align': "justify", position: "fixed",
+ left:0, top:0, width: "100%", height: "100%",
+ "background-color": "rgba(0, 0, 0, 0.8)", 'z-index':2000, 'padding':'3px'} );
+ $('#_code').hide();
+ $('#_code').click(closePopup);
+}
+// --- end of code popup section ---div as wide as the window. This div is a bit transparent. Then I hide it. I also take care to its z-index value to be sure it is behind all elements.div of class code, I copy the content into this new wide div, and I show it. Really simple but really efficient. No need to use a jQuery plugin.
+
+
+
+
+
+
+
+ Published on 2010-06-19
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2010-07-07-CSS-rendering-problems-by-navigator/index.html b/src/Scratch/en/blog/2010-07-07-CSS-rendering-problems-by-navigator/index.html
new file mode 100644
index 0000000..b98692c
--- /dev/null
+++ b/src/Scratch/en/blog/2010-07-07-CSS-rendering-problems-by-navigator/index.html
@@ -0,0 +1,120 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Cappuccino vs jQuery
+
+
+
+
+
+
+
+
+
+
+
+
+
+What this widget do?
+
+
+hash(masterPassword+domainName)
+
+
+domainName=domaine_Name_Of_URL(url)
+hash=sha1( masterPassword + leakedTimes + domainName )
+if ( kind == 'base64' )
+ hash=base64(hash)
+end
+return hash[0..maxlength]
+
+Cappuccino
+
+
+
+
+onChange on the text fields.jQuery
+My conclusion
+
+
+
+
+
+
+
+
+
+
+ Published on 2010-07-05
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2010-07-09-Indecidabilities/index.html b/src/Scratch/en/blog/2010-07-09-Indecidabilities/index.html
new file mode 100644
index 0000000..71740e7
--- /dev/null
+++ b/src/Scratch/en/blog/2010-07-09-Indecidabilities/index.html
@@ -0,0 +1,201 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Do not use CSS gradient with Chrome
+
+
+
+
+
+
+
+
+Gradient
+-webkit-gradient on Chrome. At least when the host is a Linux.Box Shadows
+-moz-box-shadow elements slow down the rendering on Firefox under Linux. But there was very few time rendering issue with Safari on Mac.Text Shadows
+Conclusion
+-webkit-gradient on Chrome browser yet. Try to use -moz-box-shadow sparingly.
+
+
+
+
+
+
+
+ Published on 2010-07-07
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2010-07-31-New-style-after-holidays/index.html b/src/Scratch/en/blog/2010-07-31-New-style-after-holidays/index.html
new file mode 100644
index 0000000..2ac5169
--- /dev/null
+++ b/src/Scratch/en/blog/2010-07-31-New-style-after-holidays/index.html
@@ -0,0 +1,107 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Undecidabilities (part 1)
+
+
+
+
+
+
+
+
+
+
+
+The Undecidabilities
+
+
+
+
+
+Undecidability due to measure errors
+
+
+
+
+
+
+
+Growing errors Undecidability
+
+
+
+
+
+Fractal Undecidability
+
+
+
+Logical Undecidability
+
+
+
+
+I’m sorry to say no. Even in a self-contained mathematical world it can be possible to create object with an unpredictable behaviour.
+
+P such that:
+
+P(x,y) return “stop” in a finite amount of time if x(y)2 will stop running.P(x,y) return “loop” in a finite amount of time if x(y) will never stop running.P(x,x).Q be the following program using the return value of P.
+Q(x) :
+ if P(x,x)="stop" then I enter in an infinite loop
+ if P(x,x)="loop" then I stop
+
+P(Q,Q)?
+
+P(Q,Q) returns “stop” that imply by construction of Q that P(Q,Q) returns “loop”.P(Q,Q) returns “loop” that means by construction of Q that P(Q,Q) return “stop”.P.
+
+
+
+
+
+
+
+
+
+
+ Published on 2010-08-11
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2010-08-23-Now-heberged-on-heroku/code/config.ru b/src/Scratch/en/blog/2010-08-23-Now-heberged-on-heroku/code/config.ru
new file mode 100644
index 0000000..48ae352
--- /dev/null
+++ b/src/Scratch/en/blog/2010-08-23-Now-heberged-on-heroku/code/config.ru
@@ -0,0 +1,42 @@
+require 'rubygems'
+require 'rack'
+require 'rack/contrib'
+require 'rack-rewrite'
+require 'mime/types'
+
+use Rack::ETag
+module ::Rack
+ class TryStatic < Static
+
+ def initialize(app, options)
+ super
+ @try = ([''] + Array(options.delete(:try)) + [''])
+ end
+
+ def call(env)
+ @next = 0
+ while @next < @try.size && 404 == (resp = super(try_next(env)))[0]
+ @next += 1
+ end
+ 404 == resp[0] ? @app.call : resp
+ end
+
+ private
+ def try_next(env)
+ env.merge('PATH_INFO' => env['PATH_INFO'] + @try[@next])
+ end
+
+ end
+end
+
+use Rack::TryStatic,
+ :root => "output", # static files root dir
+ :urls => %w[/], # match all requests
+ :try => ['.html', 'index.html', '/index.html'] # try these postfixes sequentially
+
+errorFile='output/Scratch/en/error/404-not_found/index.html'
+run lambda { [404, {
+ "Last-Modified" => File.mtime(errorFile).httpdate,
+ "Content-Type" => "text/html",
+ "Content-Length" => File.size(errorFile).to_s
+ }, File.read(errorFile)] }
diff --git a/src/Scratch/en/blog/2010-08-23-Now-heberged-on-heroku/index.html b/src/Scratch/en/blog/2010-08-23-Now-heberged-on-heroku/index.html
new file mode 100644
index 0000000..a37f3a8
--- /dev/null
+++ b/src/Scratch/en/blog/2010-08-23-Now-heberged-on-heroku/index.html
@@ -0,0 +1,168 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ New style after holidays
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ Published on 2010-07-31
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2010-08-31-send-mail-from-command-line-with-attached-file/index.html b/src/Scratch/en/blog/2010-08-31-send-mail-from-command-line-with-attached-file/index.html
new file mode 100644
index 0000000..281f000
--- /dev/null
+++ b/src/Scratch/en/blog/2010-08-31-send-mail-from-command-line-with-attached-file/index.html
@@ -0,0 +1,142 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Now hosted by heroku
+ Host static website on Heroku
+
+
+
+
+
+
+ Now on Heroku
+/output. You only need to create a config.ru1 file:
+require 'rubygems'
+require 'rack'
+require 'rack/contrib'
+require 'rack-rewrite'
+require 'mime/types'
+
+use Rack::ETag
+module ::Rack
+ class TryStatic < Static
+
+ def initialize(app, options)
+ super
+ @try = ([''] + Array(options.delete(:try)) + [''])
+ end
+
+ def call(env)
+ @next = 0
+ while @next < @try.size && 404 == (resp = super(try_next(env)))[0]
+ @next += 1
+ end
+ 404 == resp[0] ? @app.call : resp
+ end
+
+ private
+ def try_next(env)
+ env.merge('PATH_INFO' => env['PATH_INFO'] + @try[@next])
+ end
+
+ end
+end
+
+use Rack::TryStatic,
+ :root => "output", # static files root dir
+ :urls => %w[/], # match all requests
+ :try => ['.html', 'index.html', '/index.html'] # try these postfixes sequentially
+
+errorFile='output/Scratch/en/error/404-not_found/index.html'
+run lambda { [404, {
+ "Last-Modified" => File.mtime(errorFile).httpdate,
+ "Content-Type" => "text/html",
+ "Content-Length" => File.size(errorFile).to_s
+ }, File.read(errorFile)] }.gems file needed to install rack middlewares.
+
+
+
+
+
+
+
+
+
+ Published on 2010-08-23
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2010-09-02-Use-git-to-calculate-trusted-mtimes/code/gitmtime.rb b/src/Scratch/en/blog/2010-09-02-Use-git-to-calculate-trusted-mtimes/code/gitmtime.rb
new file mode 100644
index 0000000..7aeec2b
--- /dev/null
+++ b/src/Scratch/en/blog/2010-09-02-Use-git-to-calculate-trusted-mtimes/code/gitmtime.rb
@@ -0,0 +1,14 @@
+def gitmtime
+ filepath=@item.path.sub('/Scratch/','content/html/').sub(/\/$/,'')
+ ext=%{.#{@item[:extension]}}
+ filepath<<=ext
+ if not FileTest.exists?(filepath)
+ filepath.sub!(ext,%{#{@item.raw_filename}#{ext}})
+ end
+ str=`git log -1 --format='%ci' -- #{filepath}`
+ if str.nil? or str.empty?
+ return Time.now
+ else
+ return DateTime.parse( str )
+ end
+end
diff --git a/src/Scratch/en/blog/2010-09-02-Use-git-to-calculate-trusted-mtimes/index.html b/src/Scratch/en/blog/2010-09-02-Use-git-to-calculate-trusted-mtimes/index.html
new file mode 100644
index 0000000..bcbf195
--- /dev/null
+++ b/src/Scratch/en/blog/2010-09-02-Use-git-to-calculate-trusted-mtimes/index.html
@@ -0,0 +1,123 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ send mail from command line with attached file
+
+
+
+
+
+
+ pine nor mutt or anything like that. Just mail and mailx..gz, .bz2 and .zip. Using .bz2 format it worked nicely, but not with other formats. Instead of having an attached file I saw this in my email.
+begin 664 fic.jpg
+M(R$O=7-R+V)I;B]E;G8@>G-H"GAL
+From: from@mail.com
+To: to@mail.com
+Subject: View the attached file
+Mime-Version: 1.0
+Content-Type: multipart/mixed; boundary="-"
+
+This is a MIME encoded message. Decode it with "Decoder"
+or any other MIME reading software. Decoder is available
+at
+ uuencode -m fic.jpg fic.jpg ~~~~~~
+
+
+
+
+
+
+
+ Published on 2010-08-31
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2010-09-02-base64-and-sha1-on-iPhone/code/iphone_base64_sha1.c b/src/Scratch/en/blog/2010-09-02-base64-and-sha1-on-iPhone/code/iphone_base64_sha1.c
new file mode 100644
index 0000000..cd98792
--- /dev/null
+++ b/src/Scratch/en/blog/2010-09-02-base64-and-sha1-on-iPhone/code/iphone_base64_sha1.c
@@ -0,0 +1,42 @@
+
+- (unsigned char *)sha1:(NSString *)baseString result:(unsigned char *)result {
+ char *c_baseString=(char *)[baseString UTF8String];
+ CC_SHA1(c_baseString, strlen(c_baseString), result);
+ return result;
+}
+
+- (NSString *)base64:(unsigned char *)result {
+ NSString *password=[[NSString alloc] init];
+ static const unsigned char cb64[65]="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+ for (int i=0; i
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Use git to calculate trusted mtimes
+
+
+
+
+
+
+ mtime of the file on the file system. But many times I modify this date just to force some recompilation. Therefore the date wasn’t a date of real modification.
+def gitmtime
+ filepath=@item.path.sub('/Scratch/','content/html/').sub(/\/$/,'')
+ ext=%{.#{@item[:extension]}}
+ filepath<<=ext
+ if not FileTest.exists?(filepath)
+ filepath.sub!(ext,%{#{@item.raw_filename}#{ext}})
+ end
+ str=`git log -1 --format='%ci' -- #{filepath}`
+ if str.nil? or str.empty?
+ return Time.now
+ else
+ return DateTime.parse( str )
+ end
+end
+
+
+
+
+
+
+
+ Published on 2010-09-02
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2010-10-06-New-Blog-Design-Constraints/index.html b/src/Scratch/en/blog/2010-10-06-New-Blog-Design-Constraints/index.html
new file mode 100644
index 0000000..c2de447
--- /dev/null
+++ b/src/Scratch/en/blog/2010-10-06-New-Blog-Design-Constraints/index.html
@@ -0,0 +1,112 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ base64 and sha1 on iPhone
+
+
+
+
+
+
+ base64 and hexadecimal version of the sha1 hash of an NSString.
+#import <CommonCrypto/CommonDigest.h>
+...
+NSString *b64_hash = [self b64_sha1:@"some NSString to be sha1'ed"];
+...
+NSString *hex_hash = [self hex_sha1:@"some NSString to be sha1'ed"];base64 algorithm must be programmed by hand on iPhone!
+
+- (unsigned char *)sha1:(NSString *)baseString result:(unsigned char *)result {
+ char *c_baseString=(char *)[baseString UTF8String];
+ CC_SHA1(c_baseString, strlen(c_baseString), result);
+ return result;
+}
+
+- (NSString *)base64:(unsigned char *)result {
+ NSString *password=[[NSString alloc] init];
+ static const unsigned char cb64[65]="ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+ for (int i=0; i<CC_SHA1_DIGEST_LENGTH; i+=3) {
+ password=[password stringByAppendingFormat:@"%c%c%c%c",
+ cb64[(result[i] &0xFC)>>2],
+ cb64[((result[i] & 0x03) << 4)
+ | ((result[i + 1] & 0xF0) >> 4)],
+ cb64[((result[i + 1] & 0x0F) << 2)
+ | ((result[i + 2] & 0xC0) >> 6)],
+ cb64[result[i+2]&0x3F]
+ ];
+ }
+ return password;
+}
+
+- (NSString *)hexadecimalRepresentation:(unsigned char *)result {
+ NSString *password=[[NSString alloc] init];
+ for (int i=0; i<CC_SHA1_DIGEST_LENGTH; i++) {
+ password=[password stringByAppendingFormat:@"%02x", result[i]];
+ }
+ return password;
+}
+
+- (NSString *)b64_sha1:(NSString *)inputString {
+ unsigned char result[CC_SHA1_DIGEST_LENGTH+1];
+ [self sha1:inputString result:result];
+ return [self base64:result];
+}
+
+- (NSString *)hex_sha1:(NSString *)inputString {
+ unsigned char result[CC_SHA1_DIGEST_LENGTH+1];
+ [self sha1:inputString result:result];
+ return [self hexadecimalRepresentation:result];
+}
+
+
+
+
+
+
+
+ Published on 2010-09-02
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2010-10-10-Secure-eMail-on-Mac-in-few-steps/index.html b/src/Scratch/en/blog/2010-10-10-Secure-eMail-on-Mac-in-few-steps/index.html
new file mode 100644
index 0000000..296e6ce
--- /dev/null
+++ b/src/Scratch/en/blog/2010-10-10-Secure-eMail-on-Mac-in-few-steps/index.html
@@ -0,0 +1,134 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ New Blog Design Constraints
+
+
+
+
+
+
+ font-shadow and gradients. Then my new design obey to the following rules:
+
+
+
+
+
+
+
+
+
+ Published on 2010-10-06
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2010-10-14-Fun-with-wav/code/wavsum.c b/src/Scratch/en/blog/2010-10-14-Fun-with-wav/code/wavsum.c
new file mode 100644
index 0000000..aa39828
--- /dev/null
+++ b/src/Scratch/en/blog/2010-10-14-Fun-with-wav/code/wavsum.c
@@ -0,0 +1,58 @@
+#include
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Secure eMail on Mac in few steps
+
+
+
+
+
+
+
+
+
+
+
+
+
+Why is it important?
+How to proceed?
+
+
+
+
+
+
+
+
+
+
+
+
+ Published on 2010-10-10
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2010-10-26-LaTeX-like-macro-and-markdown/code/macros.rb b/src/Scratch/en/blog/2010-10-26-LaTeX-like-macro-and-markdown/code/macros.rb
new file mode 100644
index 0000000..17ebf55
--- /dev/null
+++ b/src/Scratch/en/blog/2010-10-26-LaTeX-like-macro-and-markdown/code/macros.rb
@@ -0,0 +1,43 @@
+# usage:
+# ---
+# ...
+# macros:
+# test: "passed test"
+# ---
+# ...
+# Here is a %test.
+#
+class Macros < Nanoc3::Filter
+ identifier :falacy
+ attr_accessor :macro
+ def initialize(arg)
+ super
+ @macro={}
+ @macro[:tlal] = %{tlàl : }
+ @macro[:tldr] = %{tl;dr: }
+ if @item.nil?
+ if not arg.nil?
+ @macro.merge!( arg )
+ end
+ else
+ if not @item[:macros].nil?
+ @macro.merge!( @item[:macros] )
+ end
+ end
+ end
+ def macro_value_for(macro_name)
+ if macro_name.nil? or macro_name=="" or @macro[macro_name.intern].nil?
+ return %{%#{macro_name}}
+ end
+ return @macro[macro_name.intern]
+ end
+ def run(content, params={})
+ content.gsub(/%(\w*)/) do |m|
+ if m != '%'
+ macro_value_for($1)
+ else
+ m
+ end
+ end
+ end
+end
diff --git a/src/Scratch/en/blog/2010-10-26-LaTeX-like-macro-and-markdown/index.html b/src/Scratch/en/blog/2010-10-26-LaTeX-like-macro-and-markdown/index.html
new file mode 100644
index 0000000..feb06d6
--- /dev/null
+++ b/src/Scratch/en/blog/2010-10-26-LaTeX-like-macro-and-markdown/index.html
@@ -0,0 +1,160 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Fun with wav
+
+
+
+
+
+
+
+
+wav file. C was easier and cleaner than Ruby..wav file. For efficiency (and fun) reasons, I had chosen C language.C for a long time. From my memory it was a pain to read and write to files. But in the end I was really impressed by the code I get. It was really clean. This is even more impressive knowing I used mostly low level functions.wav file has an header containing many metadata. This header was optimized to take as few space as possible. The header is then a block of packed bytes.
+
+RIFF in ASCII,C than in most higher level language. Proof: I only have to search on the web the complete header format and write it in a struct.
+struct wavfile
+{
+ char id[4]; // should always contain "RIFF"
+ int totallength; // total file length minus 8
+ char wavefmt[8]; // should be "WAVEfmt "
+ int format; // 16 for PCM format
+ short pcm; // 1 for PCM format
+ short channels; // channels
+ int frequency; // sampling frequency
+ int bytes_per_second;
+ short bytes_by_capture;
+ short bits_per_sample;
+ char data[4]; // should always contain "data"
+ int bytes_in_data;
+};C I simply written:C, to read a sequence of 2 Bytes numbers I only had to write:
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+
+struct wavfile
+{
+ char id[4]; // should always contain "RIFF"
+ int totallength; // total file length minus 8
+ char wavefmt[8]; // should be "WAVEfmt "
+ int format; // 16 for PCM format
+ short pcm; // 1 for PCM format
+ short channels; // channels
+ int frequency; // sampling frequency
+ int bytes_per_second;
+ short bytes_by_capture;
+ short bits_per_sample;
+ char data[4]; // should always contain "data"
+ int bytes_in_data;
+};
+
+int main(int argc, char *argv[]) {
+ char *filename=argv[1];
+ FILE *wav = fopen(filename,"rb");
+ struct wavfile header;
+
+ if ( wav == NULL ) {
+ fprintf(stderr,"Can't open input file %s", filename);
+ exit(1);
+ }
+
+ // read header
+ if ( fread(&header,sizeof(header),1,wav) < 1 )
+ {
+ fprintf(stderr,"Can't read file header\n");
+ exit(1);
+ }
+ if ( header.id[0] != 'R'
+ || header.id[1] != 'I'
+ || header.id[2] != 'F'
+ || header.id[3] != 'F' ) {
+ fprintf(stderr,"ERROR: Not wav format\n");
+ exit(1);
+ }
+
+ fprintf(stderr,"wav format\n");
+
+ // read data
+ long sum=0;
+ short value=0;
+ while( fread(&value,sizeof(value),1,wav) ) {
+ // fprintf(stderr,"%d\n", value);
+ if (value<0) { value=-value; }
+ sum += value;
+ }
+ printf("%ld\n",sum);
+ exit(0);
+}C is clearly far superior than Ruby to handle this simple tasks.int16_t instead of short and int instead of int.
+
+gcc. The new code make more tests but still don’t use mmap. Here it is:
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h> // for memcmp
+#include <stdint.h> // for int16_t and int32_t
+
+struct wavfile
+{
+ char id[4]; // should always contain "RIFF"
+ int32_t totallength; // total file length minus 8
+ char wavefmt[8]; // should be "WAVEfmt "
+ int32_t format; // 16 for PCM format
+ int16_t pcm; // 1 for PCM format
+ int16_t channels; // channels
+ int32_t frequency; // sampling frequency
+ int32_t bytes_per_second;
+ int16_t bytes_by_capture;
+ int16_t bits_per_sample;
+ char data[4]; // should always contain "data"
+ int32_t bytes_in_data;
+} __attribute__((__packed__));
+
+int is_big_endian(void) {
+ union {
+ uint32_t i;
+ char c[4];
+ } bint = {0x01000000};
+ return bint.c[0]==1;
+}
+
+int main(int argc, char *argv[]) {
+ char *filename=argv[1];
+ FILE *wav = fopen(filename,"rb");
+ struct wavfile header;
+
+ if ( wav == NULL ) {
+ fprintf(stderr,"Can't open input file %s\n", filename);
+ exit(1);
+ }
+
+ // read header
+ if ( fread(&header,sizeof(header),1,wav) < 1 ) {
+ fprintf(stderr,"Can't read input file header %s\n", filename);
+ exit(1);
+ }
+
+ // if wav file isn't the same endianness than the current environment
+ // we quit
+ if ( is_big_endian() ) {
+ if ( memcmp( header.id,"RIFX", 4) != 0 ) {
+ fprintf(stderr,"ERROR: %s is not a big endian wav file\n", filename);
+ exit(1);
+ }
+ } else {
+ if ( memcmp( header.id,"RIFF", 4) != 0 ) {
+ fprintf(stderr,"ERROR: %s is not a little endian wav file\n", filename);
+ exit(1);
+ }
+ }
+
+ if ( memcmp( header.wavefmt, "WAVEfmt ", 8) != 0
+ || memcmp( header.data, "data", 4) != 0
+ ) {
+ fprintf(stderr,"ERROR: Not wav format\n");
+ exit(1);
+ }
+ if (header.format != 16) {
+ fprintf(stderr,"\nERROR: not 16 bit wav format.");
+ exit(1);
+ }
+ fprintf(stderr,"format: %d bits", header.format);
+ if (header.format == 16) {
+ fprintf(stderr,", PCM");
+ } else {
+ fprintf(stderr,", not PCM (%d)", header.format);
+ }
+ if (header.pcm == 1) {
+ fprintf(stderr, " uncompressed" );
+ } else {
+ fprintf(stderr, " compressed" );
+ }
+ fprintf(stderr,", channel %d", header.pcm);
+ fprintf(stderr,", freq %d", header.frequency );
+ fprintf(stderr,", %d bytes per sec", header.bytes_per_second );
+ fprintf(stderr,", %d bytes by capture", header.bytes_by_capture );
+ fprintf(stderr,", %d bits per sample", header.bytes_by_capture );
+ fprintf(stderr,"\n" );
+
+ if ( memcmp( header.data, "data", 4) != 0 ) {
+ fprintf(stderr,"ERROR: Prrroblem?\n");
+ exit(1);
+ }
+ fprintf(stderr,"wav format\n");
+
+ // read data
+ long long sum=0;
+ int16_t value;
+ int i=0;
+ fprintf(stderr,"---\n", value);
+ while( fread(&value,sizeof(value),1,wav) ) {
+ if (value<0) { value=-value; }
+ sum += value;
+ }
+ printf("%lld\n",sum);
+ exit(0);
+}
+#!/usr/bin/env python
+from struct import calcsize, unpack
+from sys import argv, exit
+
+def word_iter(f):
+ while True:
+ _bytes = f.read(2)
+
+ if len(_bytes) != 2:
+ raise StopIteration
+
+ yield unpack("=h", _bytes)[0]
+
+try:
+ with open(argv[1], "rb") as f:
+ wav = "=4ci8cihhiihh4ci"
+ wav_size = calcsize(wav)
+ metadata = unpack(wav, f.read(wav_size))
+
+ if "".join(metadata[:4]) != "RIFF":
+ print "error: not wav file."
+ exit(1)
+
+ print sum(abs(word) for word in word_iter(f))
+except IOError:
+ print "error: can't open input file '%s'." % argv[1]
+ exit(1)
+ data = ARGF.read
+ keys = %w[id totallength wavefmt format
+ pcm channels frequency bytes_per_second
+ bytes_by_capture bits_per_sample
+ data bytes_in_data sum
+ ]
+ values = data.unpack 'Z4 i Z8 i s s i i s s Z4 i s*'
+ sum = values.drop(12).map(&:abs).inject(:+)
+ keys.zip(values.take(12) << sum) {|k, v|
+ puts "#{k.ljust 17}: #{v}"
+ }
+
+
+
+
+
+
+
+ Published on 2010-10-14
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2011-01-03-Happy-New-Year/index.html b/src/Scratch/en/blog/2011-01-03-Happy-New-Year/index.html
new file mode 100644
index 0000000..86a8555
--- /dev/null
+++ b/src/Scratch/en/blog/2011-01-03-Happy-New-Year/index.html
@@ -0,0 +1,109 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ LaTeX like macro for markdown
+
+
+
+
+
+
+
+
+
+
+
+nanoc user, simply put this file in your lib directory.
+# usage:
+# ---
+# ...
+# macros:
+# test: "passed test"
+# ---
+# ...
+# Here is a Just a test.
+#
+class Macros < Nanoc3::Filter
+ identifier :falacy
+ attr_accessor :macro
+ def initialize(arg)
+ super
+ @macro={}
+ @macro[:tlal] = %{<span class="sc"><abbr title="Trop long à lire">tlàl</abbr> : </span>}
+ @macro[:tldr] = %{<span class="sc"><abbr title="Too long; didn't read">tl;dr</abbr>: </span>}
+ if @item.nil?
+ if not arg.nil?
+ @macro.merge!( arg )
+ end
+ else
+ if not @item[:macros].nil?
+ @macro.merge!( @item[:macros] )
+ end
+ end
+ end
+ def macro_value_for(macro_name)
+ if macro_name.nil? or macro_name=="" or @macro[macro_name.intern].nil?
+ return %{%#{macro_name}}
+ end
+ return @macro[macro_name.intern]
+ end
+ def run(content, params={})
+ content.gsub(/%(\w*)/) do |m|
+ if m != '%'
+ macro_value_for($1)
+ else
+ m
+ end
+ end
+ end
+end
+
+
+
+
+
+
+
+ Published on 2010-10-26
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2011-01-03-Why-I-sadly-won-t-use-coffeescript/index.html b/src/Scratch/en/blog/2011-01-03-Why-I-sadly-won-t-use-coffeescript/index.html
new file mode 100644
index 0000000..b541469
--- /dev/null
+++ b/src/Scratch/en/blog/2011-01-03-Why-I-sadly-won-t-use-coffeescript/index.html
@@ -0,0 +1,179 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Happy New Year
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ Published on 2011-01-01
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/2011-04-20-Now-hosted-on-github/index.html b/src/Scratch/en/blog/2011-04-20-Now-hosted-on-github/index.html
new file mode 100644
index 0000000..8a5c827
--- /dev/null
+++ b/src/Scratch/en/blog/2011-04-20-Now-hosted-on-github/index.html
@@ -0,0 +1,108 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Why I won't use CoffeeScript (sadly)
+
+
+
+
+
+
+
+
+
+
+
+CoffeeScript.eval function. And as Denis said: “it is time to use Coffeescript as a javascript with Ruby-like syntax not a Ruby-like programming language”.
+
+
+
+this doesn’t work really well),
+
+node.js and use npm just to use CoffeeScript. It wasn’t a big deal but it wasn’t as straightfoward as I expected either.--watch option of coffee was also really helpful to help in the translation. But I had to write my own shell script in order to follow an entire directory tree.eval. But in order to work, the string in the eval must be written in pure javascript not in coffee. It was like writing in two different languages. Really not so good.Conclusion
+
+
+
+
+
+
node.js, npm and CoffeeScript,Digression
+ruby2js script for example2. But I believe it would be a really hard task just to simulate the access of current class for example.@x translate into this.x. But the following code will not do what I should expect. Call the foo function of the current class.
+->
+class MyClass
+ foo: ->
+ alert('ok')
+
+ bar: ->
+ $('#content').load( '/content.html', ( -> @foo(x) ) )
+ # That won't call MyClass.foo
+->
+class MyClass
+ foo: ->
+ alert('ok')
+
+ bar: ->
+ self=this
+ $('#content').load( '/content.html', ( -> self.foo(x) ) )@ notation lose most of its interrest for me.
+
+
+
+
+
+
+
+
+
+ Published on 2011-01-03
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/A-more-convenient-diff/code/ydiff b/src/Scratch/en/blog/A-more-convenient-diff/code/ydiff
new file mode 100644
index 0000000..90d6c85
--- /dev/null
+++ b/src/Scratch/en/blog/A-more-convenient-diff/code/ydiff
@@ -0,0 +1,22 @@
+#!/usr/bin/env zsh
+
+# Load colors helpers
+autoload -U colors && colors
+
+function colorize_diff {
+ while read line; do
+ case ${line[0]} in
+ +) print -n $fg[green];;
+ -) print -n $fg[red];;
+ @) # Display in cyan the @@ positions @@
+ if [[ ${line[1]} = '@' ]]; then
+ line=$(print $line | perl -pe 's#(\@\@[^\@]*\@\@)(.*)$#'$fg[cyan]'$1'$reset_color'$2#')
+ fi;;
+
+ esac
+ print -- $line
+ print -n $reset_color
+ done
+}
+
+diff -u $* | colorize_diff
diff --git a/src/Scratch/en/blog/A-more-convenient-diff/index.html b/src/Scratch/en/blog/A-more-convenient-diff/index.html
new file mode 100644
index 0000000..e03409c
--- /dev/null
+++ b/src/Scratch/en/blog/A-more-convenient-diff/index.html
@@ -0,0 +1,130 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Now hosted on github
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+ Published on 2011-04-20
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/Category-Theory-Presentation/index.html b/src/Scratch/en/blog/Category-Theory-Presentation/index.html
new file mode 100644
index 0000000..e35ccaa
--- /dev/null
+++ b/src/Scratch/en/blog/Category-Theory-Presentation/index.html
@@ -0,0 +1,1068 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ A more convenient diff
+
+
+
+
+
+
+ git it will use a better formatting and colorize it.diff à la git.
+ #!/usr/bin/env zsh
+
+# Load colors helpers
+autoload -U colors && colors
+
+function colorize_diff {
+ while read line; do
+ case ${line[0]} in
+ +) print -n $fg[green];;
+ -) print -n $fg[red];;
+ @) # Display in cyan the @@ positions @@
+ if [[ ${line[1]} = '@' ]]; then
+ line=$(print $line | perl -pe 's#(\@\@[^\@]*\@\@)(.*)$#'$fg[cyan]'$1'$reset_color'$2#')
+ fi;;
+
+ esac
+ print -- $line
+ print -n $reset_color
+ done
+}
+
+diff -u $* | colorize_diff
+
+
+
+
+
+
+
+ Published on 2011-08-17
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/Hakyll-setup/index.html b/src/Scratch/en/blog/Hakyll-setup/index.html
new file mode 100644
index 0000000..ae8490a
--- /dev/null
+++ b/src/Scratch/en/blog/Hakyll-setup/index.html
@@ -0,0 +1,520 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Category Theory Presentation
+
+
+
+
+
+
+ 
+
+
+
+Not really about: Cat & glory
+
General Overview
+
+
+
+
+
1942-45, Samuel Eilenberg & Saunders Mac Lane
+
+
formalism abstraction, package entire theory★
Physics, Quantum Physics, Topology, Logic, Computer Science☆
☆: Physics, Topology, Logic and Computation: A Rosetta Stone, John C. Baez, Mike Stay, 2009
+Math Programming relation
+
+
Certainly a vocabulary problem.Vocabulary
+
+
+
+Programmer Translation
+
+
+
+
+
+Mathematician
+
+Programmer
+
+Morphism
+
+Arrow
+
+Monoid
+
+String-like
+
+Preorder
+
+Acyclic graph
+
+Isomorph
+
+The same
+
+Natural transformation
+
+rearrangement function
+
+Funny Category
+
+LOLCat
+ Category: Objects
+
+
+
+Category: Morphisms
+
+
+
+
+\(\hom{A,B}\) is a collection of morphisms
+\(f:A→B\) denote the fact \(f\) belongs to \(\hom{A,B}\)Category: Composition
+
+Category laws: neutral element
+
+such that for each \(f:A→B\):
+Category laws: Associativity
+
+Commutative diagrams
+
+
+ 
+ Question Time!
+
+
+Can this be a category?
+
+ 
+
NO
+ 
+ Can this be a category?
+
+
NO
+ 
+
+ \(h∘(g∘f)=h∘\id_A=h\)
+ but \(h≠f\)
+ NO
+ Categories Examples
+
+
+Categories Everywhere?
+
+
+
+(.) )Smaller Examples
+
+Strings
+
+
+
+(++)
+
+"" ++ u = u = u ++ "" (u ++ v) ++ w = u ++ (v ++ w) Finite Example?
+
+Graph
+
+
+
+
+Number construction
+
+Each Numbers as a whole category
+
+Degenerated Categories: Monoids
+
+
+
+(Integer,0,+), (Integer,1,*),
+(Strings,"",++), for each a, ([a],[],++)
+Degenerated Categories: Preorders \((P,≤)\)
+
+
+
+
+Degenerated Categories: Discrete Categories
+
+
+Any Set
+Isomorph
+
isomorphism: \(f:A→B\) which can be "undone" i.e.
\(∃g:B→A\), \(g∘f=id_A\) & \(f∘g=id_B\)
in this case, \(A\) & \(B\) are isomorphic.
In Category Theory, = is in fact mostly ≌.
For example in commutative diagrams.Functor Example (ob → ob)
+
+
+Functor Example (hom → hom)
+
+
+Functor Example
+
+
+Endofunctors
+
+
+Category of Categories
+
+
+
+
+Hask
+
+
+
+
+
+(.) Haskell function composition
+undefined.Haskell Functor intuition
+
+
+Functor as boxes
+
+
+Functor as boxes
+
+
+Functor as boxes
+
+
+Category of \(\Hask\) Endofunctors
+
+Natural Transformations
+
A natural transformation: familly η ; \(η_X\in\hom{\D}\) for \(X\in\ob{\C}\) s.t.F a -> G a
Rearragement functions only.Natural Transformation Examples (1/4)
+
+data List a = Nil | Cons a (List a)
+toList :: [a] -> List a
+toList [] = Nil
+toList (x:xs) = Cons x (toList xs)toList is a natural transformation. It is also a morphism from [] to List in the Category of \(\Hask\) endofunctors.
+
+Natural Transformation Examples (2/4)
+
+data List a = Nil | Cons a (List a)
+toHList :: List a -> [a]
+toHList Nil = []
+toHList (Cons x xs) = x:toHList xstoHList is a natural transformation. It is also a morphism from List to [] in the Category of \(\Hask\) endofunctors.
+
toList . toHList = id & toHList . toList = id
therefore [] & List are isomorph. Natural Transformation Examples (3/4)
+
+toMaybe :: [a] -> Maybe a
+toMaybe [] = Nothing
+toMaybe (x:xs) = Just xtoMaybe is a natural transformation. It is also a morphism from [] to Maybe in the Category of \(\Hask\) endofunctors.
+
+Natural Transformation Examples (4/4)
+
+mToList :: Maybe a -> [a]
+mToList Nothing = []
+mToList Just x = [x]toMaybe is a natural transformation. It is also a morphism from [] to Maybe in the Category of \(\Hask\) endofunctors.
+![relation between [] and Maybe](http://yogsototh.github.com/Category-Theory-Presentation/categories/img/mp/maybe-list-endofunctor-morphsm.png)
Hint: Bool lists longer than 1.
+fold
+κατα-morphism
+
+
+
+
+
+
+
+
+
+ Published on 2012-12-12
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/Haskell-Mandelbrot/code/animandel.hs b/src/Scratch/en/blog/Haskell-Mandelbrot/code/animandel.hs
new file mode 100644
index 0000000..6a81748
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-Mandelbrot/code/animandel.hs
@@ -0,0 +1,8 @@
+a=27;b=79;c=C(-2.0,-1.0);d=C(1.0,1.0);e=C(-2.501,-1.003)
+newtype C = C (Double,Double) deriving (Show,Eq)
+instance Num C where C(x,y)*C(z,t)=C(z*x-y*t,y*z+x*t);C(x,y)+C(z,t)=C(x+z,y+t);abs(C(x,y))=C(sqrt(x*x+y*y),0.0)
+r(C(x,y))=x;i(C(x,y))=y
+f c z 0=0;f c z n=if(r(abs(z))>2)then n else f c ((z*z)+c) (n-1)
+h j k = map (\z->(f (C z) (C(0,0)) 32,(fst z>l - q/2))) [(x,y)|y<-[p,(p+((o-p)/a))..o],x<-[m,(m + q)..l]] where o=i k;p=i j;m=r j;l=r k;q=(l-m)/b
+u j k = concat $ map v $ h j k where v (i,p)=(" .,`'°\":;-+oO0123456789=!%*§&$@#"!!i):rst p;rst True="\n";rst False=""
+main = putStrLn $ im 0 where cl n (C (x,y))=let cs=(1.1**n-1) in C ((x+cs*(r e))/cs+1,(y+cs*(i e))/cs+1);bl n=cl n c;tr n=cl n d;im n=u (bl n) (tr n)++"\x1b[H\x1b[25A"++im (n+1)
diff --git a/src/Scratch/en/blog/Haskell-Mandelbrot/index.html b/src/Scratch/en/blog/Haskell-Mandelbrot/index.html
new file mode 100644
index 0000000..7b826f5
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-Mandelbrot/index.html
@@ -0,0 +1,205 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Hakyll setup
+
+
+
+
+
+
+
+
+
+
+
+index.html, etc…make).
+
+
+A First Level Header
+====================
+
+A Second Level Header
+---------------------
+
+Who would cross the Bridge of Death must answer me
+these questions three, ere the other side he see.
+This is just a regular paragraph.
+
+Ask me the questions, bridgekeeper. I am not afraid.
+
+### Header 3
+
+> This is a blockquote.
+>
+> This is the second paragraph in the blockquote.
+>
+> ## This is an H2 in a blockquote
+
+git push. My blog is hosted on github.
+
+
+
+The concepts and syntax
+
+
+
+
+
+_site.
+-- for each file in the static directory
+match "static/*" do
+ -- don't change its name nor directory
+ route idRoute
+ -- don't change its content
+ compile copyFileCompilerstatic/foo.jpg to _site/static/foo.jpg. I concede this is a bit overkill for a simple cp. Now how to write a markdown file and generate an html one?
+-- for each file with md extension in the "posts/" directory
+match "posts/*.md" do
+ -- change its extension to html
+ route $ setExtension "html"
+ -- use pandoc library to compile the markdown content into html
+ compile $ pandocCompilerposts/foo.md, it will create a file _site/posts/foo.html.posts/foo.md contains_site/posts/foo.html, will contain_site/posts/cthulhu.html is not a complete html file. It doesn’t have any header nor footer, etc… This is where you use templates. I simply add a new directive in the compile block.
+match "posts/*.md" do
+ route $ setExtension "html"
+ compile $ pandocCompiler
+ -- use the template with the current content
+ >>= loadAndApplyTemplate "templates/post.html" defaultContexttemplates/posts.html contains:
+<html>
+ <head>
+ <title>How could I get the title?</title>
+ </head>
+ <body>
+ $body$
+ </body>
+</html>cthulhu.html contains (indentation added for readability):
+<html>
+ <head>
+ <title>How could I get the title?</title>
+ </head>
+ <body>
+ <h1>Cthulhu</h1>
+ <p>ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn</p>
+ </body>
+</html>Contexts. For this, we first need to add some metadatas to our markdown1.
+
+Real customization
+
+
+Use SASS
+unixFilter. Of course you’ll have to install SASS (gem install sass). And we also use compressCss to gain some space.
+match "css/*" $ do
+ route $ setExtension "css"
+ compile $ getResourceString >>=
+ withItemBody (unixFilter "sass" ["--trace"]) >>=
+ return . fmap compressCssAdd keywords
+Context that will contains the meta tag.
+-- metaKeywordContext will return a Context containing a String
+metaKeywordContext :: Context String
+-- can be reached using $metaKeywords$ in the templates
+-- Use the current item (markdown file)
+metaKeywordContext = field "metaKeywords" $ \item -> do
+ -- tags contains the content of the "tags" metadata
+ -- inside the item (understand the source)
+ tags <- getMetadataField (itemIdentifier item) "tags"
+ -- if tags is empty return an empty string
+ -- in the other case return
+ -- <meta name="keywords" content="$tags$">
+ return $ maybe "" showMetaTags tags
+ where
+ showMetaTags t = "<meta name=\"keywords\" content=\""
+ ++ t ++ "\">\n"Context to the loadAndApplyTemplate function:
+match "posts/*.md" do
+ route $ setExtension "html"
+ compile $ pandocCompiler
+ -- use the template with the current content
+ >>= loadAndApplyTemplate "templates/post.html"
+ (defaultContext <> metaKeywordContext)
+
+
+{-# LANGUAGE OverloadedStrings #-}
+import Control.Monad (forM,forM_)
+import Data.List (sortBy,isInfixOf)
+import Data.Monoid ((<>),mconcat)
+import Data.Ord (comparing)
+import Hakyll
+import System.Locale (defaultTimeLocale)
+import System.FilePath.Posix (takeBaseName,takeDirectory
+ ,(</>),splitFileName)Simplify url
+
+http://domain.name/post/title-of-the-post/.html extension. We have to change the default Hakyll route behavior. We create another function niceRoute.
+-- replace a foo/bar.md by foo/bar/index.html
+-- this way the url looks like: foo/bar in most browsers
+niceRoute :: Routes
+niceRoute = customRoute createIndexRoute
+ where
+ createIndexRoute ident =
+ takeDirectory p </> takeBaseName p </> "index.html"
+ where p=toFilePath identfoo/index.html link instead of a clean foo/ in some content?/index.html to all our links.
+-- replace url of the form foo/bar/index.html by foo/bar
+removeIndexHtml :: Item String -> Compiler (Item String)
+removeIndexHtml item = return $ fmap (withUrls removeIndexStr) item
+ where
+ removeIndexStr :: String -> String
+ removeIndexStr url = case splitFileName url of
+ (dir, "index.html") | isLocal dir -> dir
+ _ -> url
+ where isLocal uri = not (isInfixOf "://" uri)
+match "posts/*.md" do
+ route $ niceRoute
+ compile $ pandocCompiler
+ -- use the template with the current content
+ >>= loadAndApplyTemplate "templates/post.html" defaultContext
+ >>= removeIndexHtmlCreate an archive page
+2013-03-20-My-New-Post.md.published. And the solution is here:
+match "archive.md" $ do
+ route $ niceRoute
+ compile $ do
+ body <- getResourceBody
+ return $ renderPandoc body
+ >>= loadAndApplyTemplate "templates/archive.html" archiveCtx
+ >>= loadAndApplyTemplate "templates/base.html" defaultContext
+ >>= removeIndexHtmltemplates/archive.html containsbase.html is a standard template (simpler than post.html).archiveCtx provide a context containing an html representation of a list of posts in the metadata named posts. It will be used in the templates/archive.html file with $posts$.
+archiveCtx =
+ defaultContext <>
+ metaKeywordContext <>
+ field "posts" (\_ -> postList createdFirst)postList returns an html representation of a list of posts given an Item sort function. The representation will apply a minimal template on all posts. Then it concatenate all the results. The template is post-item.html:
+postList :: [Item String] -> Compiler [Item String]
+ -> Compiler String
+postList sortFilter = do
+ -- sorted posts
+ posts <- loadAll "post/*" >>= sortFilter
+ itemTpl <- loadBody "templates/post-item.html"
+ -- we apply the template to all post
+ -- and we concatenate the result.
+ -- list is a string
+ list <- applyTemplateList itemTpl defaultContext posts
+ return listcreatedFirst sort a list of item and put it inside Compiler context. We need to be in the Compiler context to access metadatas.
+createdFirst :: [Item String] -> Compiler [Item String]
+createdFirst items = do
+ -- itemsWithTime is a list of couple (date,item)
+ itemsWithTime <- forM items $ \item -> do
+ -- getItemUTC will look for the metadata "published" or "date"
+ -- then it will try to get the date from some standard formats
+ utc <- getItemUTC defaultTimeLocale $ itemIdentifier item
+ return (utc,item)
+ -- we return a sorted item list
+ return $ map snd $ reverse $ sortBy (comparing fst) itemsWithTimeCreate an rss feed
+
+
+
+match "posts/*.md" do
+ route $ setExtension "html"
+ compile $ pandocCompiler
+ -- save a snapshot to be used later in rss generation
+ >>= saveSnapshot "content"
+ >>= loadAndApplyTemplate "templates/post.html" defaultContextmatch, we use create:
+create ["feed.xml"] $ do
+ route idRoute
+ compile $ do
+ -- load all "content" snapshots of all posts
+ loadAllSnapshots "posts/*" "content"
+ -- take the latest 10
+ >>= (fmap (take 10)) . createdFirst
+ -- renderAntom feed using some configuration
+ >>= renderAtom feedConfiguration feedCtx
+ where
+ feedCtx :: Context String
+ feedCtx = defaultContext <>
+ -- $description$ will render as the post body
+ bodyField "description"feedConfiguration contains some general informations about the feed.
+feedConfiguration :: FeedConfiguration
+feedConfiguration = FeedConfiguration
+ { feedTitle = "Great Old Ones"
+ , feedDescription = "This feed provide information about Great Old Ones"
+ , feedAuthorName = "Abdul Alhazred"
+ , feedAuthorEmail = "abdul.alhazred@great-old-ones.com"
+ , feedRoot = "http://great-old-ones.com"
+ }Filter the content
+String -> String.
+markdownPostBehavior = do
+ route $ niceRoute
+ compile $ do
+ body <- getResourceBody
+ prefilteredText <- return $ (fmap preFilters body)
+ return $ renderPandoc prefilteredText
+ >>= applyFilter postFilters
+ >>= saveSnapshot "content"
+ >>= loadAndApplyTemplate "templates/post.html" yContext
+ >>= loadAndApplyTemplate "templates/boilerplate.html" yContext
+ >>= relativizeUrls
+ >>= removeIndexHtml
+applyFilter strfilter str = return $ (fmap $ strfilter) str
+preFilters :: String -> String
+postFilters :: String -> StringAdd abbreviations support
+
+abbreviationFilter :: String -> String
+abbreviationFilter = replaceAll "%[a-zA-Z0-9_]*" newnaming
+ where
+ newnaming matched = case M.lookup (tail matched) abbreviations of
+ Nothing -> matched
+ Just v -> v
+abbreviations :: Map String String
+abbreviations = M.fromList
+ [ ("html", "<span class=\"sc\">html</span>")
+ , ("css", "<span class=\"sc\">css</span>")
+ , ("svg", "<span class=\"sc\">svg</span>")
+ , ("xml", "<span class=\"sc\">xml</span>")
+ , ("xslt", "<span class=\"sc\">xslt</span>") ]Map if there is a corresponding abbreviation. If there is one, we replace the content. Otherwise we do nothing.Manage two languages
+
+data Trad = Trad { frTrad :: String, enTrad :: String }
+
+trads :: Map String Trad
+trads = M.fromList $ map toTrad [
+ ("changeLanguage",
+ ("English"
+ , "Français"))
+ ,("switchCss",
+ ("Changer de theme"
+ ,"Change Theme"))
+ ,("socialPrivacy",
+ ("Ces liens sociaux préservent votre vie privée"
+ ,"These social sharing links preserve your privacy"))
+ ]
+ where
+ toTrad (key,(french,english)) =
+ (key, Trad { frTrad = french , enTrad = english })
+tradsContext :: Context a
+tradsContext = mconcat (map addTrad (M.keys trads))
+ where
+ addTrad :: String -> Context a
+ addTrad name =
+ field name $ \item -> do
+ lang <- itemLang item
+ case M.lookup name trads of
+ Just (Trad lmap) -> case M.lookup (L lang) lmap of
+ Just tr -> return tr
+ Nothing -> return ("NO TRANSLATION FOR " ++ name)
+ Nothing -> return ("NO TRANSLATION FOR " ++ name)Conclusion
+
+
+foo.hs which could then be downloaded.
+<h1>Title</h1>
+
+<p>content</p>
+
+<a href="code/foo.hs">Download foo.hs</a>
+<pre><code>main = putStrLn "Cthulhu!"</code></pre>
+
+
+foo.md.metadata).↩
+
+
+
+
+
+
+
+ Published on 2013-03-16
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/00_Introduction.lhs b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/00_Introduction.lhs
new file mode 100644
index 0000000..1d9df7d
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/00_Introduction.lhs
@@ -0,0 +1,53 @@
+ ## Introduction
+
+In my
+[preceding article](/Scratch/en/blog/Haskell-the-Hard-Way/) I introduced Haskell.
+
+This article goes further.
+It will show how to use functional programming with interactive programs.
+But more than that, it will show how to organize your code in a functional way.
+This article is more about functional paradigm than functional language.
+The code organization can be used in most imperative language.
+
+As Haskell is designed for functional paradigm, it is easier to use in this context.
+In reality, the firsts sections will use an imperative paradigm.
+As you can use functional paradigm in imperative language,
+you can also use imperative paradigm in functional languages.
+
+This article is about creating an useful and clean program.
+It can interact with the user in real time.
+It uses OpenGL, a library with imperative programming foundations.
+Despite this fact,
+most of the final code will remain in the pure part (no `IO`).
+
+I believe the main audience for this article are:
+
+- Haskell programmer looking for an OpengGL tutorial.
+- People interested in program organization (programming language agnostic).
+- Fractal lovers and in particular 3D fractal.
+- People interested in user interaction in a functional paradigm.
+
+I had in mind for some time now to make a Mandelbrot set explorer.
+I had already written a [command line Mandelbrot set generator in Haskell](http://github.com/yogsototh/mandelbrot.git).
+This utility is highly parallel; it uses the `repa` package[^001].
+
+[^001]: Unfortunately, I couldn't make this program to work on my Mac. More precisely, I couldn't make the [DevIL](http://openil.sourceforge.net/) library work on Mac to output the image. Yes I have done a `brew install libdevil`. But even a minimal program who simply write some `jpg` didn't worked. I tried both with `Haskell` and `C`.
+
+This time, we will not parallelize the computation.
+Instead, we will display the Mandelbrot set extended in 3D using OpenGL and Haskell.
+You will be able to move it using your keyboard.
+This object is a Mandelbrot set in the plan (z=0),
+and something nice to see in 3D.
+
+Here are some screenshots of the result:
+
+blogfigure("GoldenMandelbulb.png","The entire Mandelbulb")
+blogfigure("3DMandelbulbDetail.png","A Mandelbulb detail")
+blogfigure("3DMandelbulbDetail2.png","Another detail of the Mandelbulb")
+
+And you can see the intermediate steps to reach this goal:
+
+blogimage("HGL_Plan.png","The parts of the article")
+
+From the 2nd section to the 4th it will be _dirtier_ and _dirtier_.
+We start cleaning the code at the 5th section.
diff --git a/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/01_Introduction/hglmandel.lhs b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/01_Introduction/hglmandel.lhs
new file mode 100644
index 0000000..954c6f8
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/01_Introduction/hglmandel.lhs
@@ -0,0 +1,182 @@
+ ## First version
+
+We can consider two parts.
+The first being mostly some boilerplate[^011].
+And the second part more focused on OpenGL and content.
+
+[^011]: Generally in Haskell you need to declare a lot of import lines.
+ This is something I find annoying.
+ In particular, it should be possible to create a special file, Import.hs
+ which make all the necessary import for you, as you generally need them all.
+ I understand why this is cleaner to force the programmer not to do so,
+ but, each time I do a copy/paste, I feel something is wrong.
+ I believe this concern can be generalized to the lack of namespace in Haskell.
+
+ ### Let's play the song of our people
+
+> import Graphics.Rendering.OpenGL
+> import Graphics.UI.GLUT
+> import Data.IORef
+
+For efficiency reason[^010001], I will not use the default Haskell `Complex` data type.
+
+[^010001]: I tried `Complex Double`, `Complex Float`, this current data type with `Double` and the actual version `Float`. For rendering a 1024x1024 Mandelbrot set it takes `Complex Double` about 6.8s, for `Complex Float` about 5.1s, for the actual version with `Double` and `Float` it takes about `1.6` sec. See these sources for testing yourself: [https://gist.github.com/2945043](https://gist.github.com/2945043). If you really want to things to go faster, use `data Complex = C {-# UNPACK #-} !Float {-# UNPACK #-} !Float`. It takes only one second instead of 1.6s.
+
+> data Complex = C (Float,Float) deriving (Show,Eq)
+
+
+> instance Num Complex where
+> fromInteger n = C (fromIntegral n,0.0)
+> C (x,y) * C (z,t) = C (z*x - y*t, y*z + x*t)
+> C (x,y) + C (z,t) = C (x+z, y+t)
+> abs (C (x,y)) = C (sqrt (x*x + y*y),0.0)
+> signum (C (x,y)) = C (signum x , 0.0)
+
+We declare some useful functions for manipulating complex numbers:
+
+> complex :: Float -> Float -> Complex
+> complex x y = C (x,y)
+>
+> real :: Complex -> Float
+> real (C (x,y)) = x
+>
+> im :: Complex -> Float
+> im (C (x,y)) = y
+>
+> magnitude :: Complex -> Float
+> magnitude = real.abs
+
+
+ ### Let us start
+
+We start by giving the main architecture of our program:
+
+> main :: IO ()
+> main = do
+> -- GLUT need to be initialized
+> (progname,_) <- getArgsAndInitialize
+> -- We will use the double buffered mode (GL constraint)
+> initialDisplayMode $= [DoubleBuffered]
+> -- We create a window with some title
+> createWindow "Mandelbrot Set with Haskell and OpenGL"
+> -- Each time we will need to update the display
+> -- we will call the function 'display'
+> displayCallback $= display
+> -- We enter the main loop
+> mainLoop
+
+Mainly, we initialize our OpenGL application.
+We declared that the function `display` will be used to render the graphics:
+
+> display = do
+> clear [ColorBuffer] -- make the window black
+> loadIdentity -- reset any transformation
+> preservingMatrix drawMandelbrot
+> swapBuffers -- refresh screen
+
+Also here, there is only one interesting line;
+the draw will occur in the function `drawMandelbrot`.
+
+This function will provide a list of draw actions.
+Remember that OpenGL is imperative by design.
+Then, one of the consequence is you must write the actions in the right order.
+No easy parallel drawing here.
+Here is the function which will render something on the screen:
+
+> drawMandelbrot =
+> -- We will print Points (not triangles for example)
+> renderPrimitive Points $ do
+> mapM_ drawColoredPoint allPoints
+> where
+> drawColoredPoint (x,y,c) = do
+> color c -- set the current color to c
+> -- then draw the point at position (x,y,0)
+> -- remember we're in 3D
+> vertex $ Vertex3 x y 0
+
+The `mapM_` function is mainly the same as map but inside a monadic context.
+More precisely, this can be transformed as a list of actions where the order is important:
+
+~~~
+drawMandelbrot =
+ renderPrimitive Points $ do
+ color color1
+ vertex $ Vertex3 x1 y1 0
+ ...
+ color colorN
+ vertex $ Vertex3 xN yN 0
+~~~
+
+We also need some kind of global variables.
+In fact, global variable are a proof of a design problem.
+We will get rid of them later.
+
+> width = 320 :: GLfloat
+> height = 320 :: GLfloat
+
+And of course our list of colored points.
+In OpenGL the default coordinate are from -1 to 1.
+
+> allPoints :: [(GLfloat,GLfloat,Color3 GLfloat)]
+> allPoints = [ (x/width,y/height,colorFromValue $ mandel x y) |
+> x <- [-width..width],
+> y <- [-height..height]]
+>
+
+We need a function which transform an integer value to some color:
+
+> colorFromValue n =
+> let
+> t :: Int -> GLfloat
+> t i = 0.5 + 0.5*cos( fromIntegral i / 10 )
+> in
+> Color3 (t n) (t (n+5)) (t (n+10))
+
+And now the `mandel` function.
+Given two coordinates in pixels, it returns some integer value:
+
+> mandel x y =
+> let r = 2.0 * x / width
+> i = 2.0 * y / height
+> in
+> f (complex r i) 0 64
+
+It uses the main Mandelbrot function for each complex \\(c\\).
+The Mandelbrot set is the set of complex number \\(c\\) such that the following sequence does not escape to infinity.
+
+Let us define \\(f_c: \mathbb{C} \to \mathbb{C}\\)
+
+$$ f_c(z) = z^2 + c $$
+
+The sequence is:
+
+$$ 0 \rightarrow f_c(0) \rightarrow f_c(f_c(0)) \rightarrow \cdots \rightarrow f^n_c(0) \rightarrow \cdots $$
+
+Of course, instead of trying to test the real limit, we just make a test after a finite number of occurrences.
+
+> f :: Complex -> Complex -> Int -> Int
+> f c z 0 = 0
+> f c z n = if (magnitude z > 2 )
+> then n
+> else f c ((z*z)+c) (n-1)
+
+Well, if you download this file (look at the bottom of this section), compile it and run it this is the result:
+
+blogimage("hglmandel_v01.png","The mandelbrot set version 1")
+
+A first very interesting property of this program is that the computation for all the points is done only once.
+It is a bit long before the first image appears, but if you resize the window, it updates instantaneously.
+This property is a direct consequence of purity.
+If you look closely, you see that `allPoints` is a pure list.
+Therefore, calling `allPoints` will always render the same result and Haskell is clever enough to use this property.
+While Haskell doesn't garbage collect `allPoints` the result is reused for free.
+We did not specified this value should be saved for later use.
+It is saved for us.
+
+See what occurs if we make the window bigger:
+
+blogimage("hglmandel_v01_too_wide.png","The mandelbrot too wide, black lines and columns")
+
+We see some black lines because we have drawn less point than there is on the surface.
+We can repair this by drawing little squares instead of just points.
+But, instead we will do something a bit different and unusual.
diff --git a/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/02_Edges/HGLMandelEdge.lhs b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/02_Edges/HGLMandelEdge.lhs
new file mode 100644
index 0000000..715db44
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/02_Edges/HGLMandelEdge.lhs
@@ -0,0 +1,152 @@
+ ## Only the edges
+
+
+
+This time, instead of drawing all points,
+we will simply draw the edges of the Mandelbrot set.
+The method I use is a rough approximation.
+I consider the Mandelbrot set to be almost convex.
+The result will be good enough for the purpose of this tutorial.
+
+We change slightly the `drawMandelbrot` function.
+We replace the `Points` by `LineLoop`
+
+> drawMandelbrot =
+> -- We will print Points (not triangles for example)
+> renderPrimitive LineLoop $ do
+> mapM_ drawColoredPoint allPoints
+> where
+> drawColoredPoint (x,y,c) = do
+> color c -- set the current color to c
+> -- then draw the point at position (x,y,0)
+> -- remember we're in 3D
+> vertex $ Vertex3 x y 0
+
+And now, we should change our list of points.
+Instead of drawing every point of the visible surface,
+we will choose only point on the surface.
+
+> allPoints = positivePoints ++
+> map (\(x,y,c) -> (x,-y,c)) (reverse positivePoints)
+
+We only need to compute the positive point.
+The Mandelbrot set is symmetric relatively to the abscisse axis.
+
+> positivePoints :: [(GLfloat,GLfloat,Color3 GLfloat)]
+> positivePoints = do
+> x <- [-width..width]
+> let y = maxZeroIndex (mandel x) 0 height (log2 height)
+> if y < 1 -- We don't draw point in the absciss
+> then []
+> else return (x/width,y/height,colorFromValue $ mandel x y)
+> where
+> log2 n = floor ((log n) / log 2)
+
+This function is interesting.
+For those not used to the list monad here is a natural language version of this function:
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ ASCII Haskell Mandelbrot
+
+
+
+
+
+
+
+a=27;b=79;c=C(-2.0,-1.0);d=C(1.0,1.0);e=C(-2.501,-1.003)
+newtype C = C (Double,Double) deriving (Show,Eq)
+instance Num C where C(x,y)*C(z,t)=C(z*x-y*t,y*z+x*t);C(x,y)+C(z,t)=C(x+z,y+t);abs(C(x,y))=C(sqrt(x*x+y*y),0.0)
+r(C(x,y))=x;i(C(x,y))=y
+f c z 0=0;f c z n=if(r(abs(z))>2)then n else f c ((z*z)+c) (n-1)
+h j k = map (\z->(f (C z) (C(0,0)) 32,(fst z>l - q/2))) [(x,y)|y<-[p,(p+((o-p)/a))..o],x<-[m,(m + q)..l]] where o=i k;p=i j;m=r j;l=r k;q=(l-m)/b
+u j k = concat $ map v $ h j k where v (i,p)=(" .,`'°\":;-+oO0123456789=!%*§&$@#"!!i):rst p;rst True="\n";rst False=""
+main = putStrLn $ im 0 where cl n (C (x,y))=let cs=(1.1**n-1) in C ((x+cs*(r e))/cs+1,(y+cs*(i e))/cs+1);bl n=cl n c;tr n=cl n d;im n=u (bl n) (tr n)++"\x1b[H\x1b[25A"++im (n+1)ghc –make animandel.hs && animandel
+###@@@@@@@$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$&&&&&WWOOClbUOWW&&$$$$$$$$$$$$$$
+##@@@@@@$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$&&&&&WWUCUb; ,jUOWW&&&$$$$$$$$$$$$
+#@@@@@$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$&&&WWWWWUb ooCWW&&&&&&$$$$$$$$
+@@@@$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$&&WWWWWWWWOU uUOWWWW&&&&&&$$$$$
+@@@$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$&&&WOUObUOOOUUUCbi rbCUUUOWWWWWOUW&$$$
+@$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$&&&&&&WWWUcr,iiCb o wUUUUUC;OW&$$
+$$$$$$$$$$$$$$$$$$$$$$$$$$&&&&&&&&&&WWWWOUC, j llW&&$
+$$$$$$$$$$$$$$$$$$$$$&&&&&&&&&&&&WWWWWWOCCbi bWWW&&
+$$$$$$$$$$$$$$$$$&&WWWWWWW&&&WWWWWWWWOUo jUOWW&&
+$$$$$$$$$$$$$$&&&WWOwOOWWWOUUOWWWWWOOUbw j.blW&
+$$$$$$$$$$$&&&&&WWWObiijbUCl bCiUUUUUCj, bOW&
+$$$$$$$$$&&&&&&&WWWOUbw ; oobCbl jUWW&
+$$$$$$$&&&&&&&WWWWOcbi ij jUW&&
+$$$$$&&WWWWWWWOwUUCbw WW&&
+WWWOWWWWWWWWWUUbo UWWW&&
+: wbUOWW&&&
+WWWOWWWWWWWWWUUbo UWWW&&
+$$$$$&&WWWWWWWOwUUCbw WW&&
+$$$$$$$&&&&&&&WWWWOcbi ij jUW&&
+$$$$$$$$$&&&&&&&WWWOUbw ; oobCbl jUWW&
+$$$$$$$$$$$&&&&&WWWObiijbUCl bCiUUUUUCj, bOW&
+$$$$$$$$$$$$$$&&&WWOwOOWWWOUUOWWWWWOOUbw j.blW&
+$$$$$$$$$$$$$$$$$&&WWWWWWW&&&WWWWWWWWOUo jUOWW&&
+$$$$$$$$$$$$$$$$$$$$$&&&&&&&&&&&&WWWWWWOCCbi bWWW&&
+$$$$$$$$$$$$$$$$$$$$$$$$$$&&&&&&&&&&WWWWOUC, j llW&&$
+@$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$&&&&&&WWWUcr,iiCb o wUUUUUC;OW&$$
+
+
+ nbvert = 30
+nbhor = 79
+zoomfactor = 1.01
+init_bottom_left = C (-2.0,-2.0)
+init_top_right = C (3.0,2.0)
+interrest = C (-1.713,-0.000)
+
+newtype Complex = C (Float,Float) deriving (Show,Eq)
+instance Num Complex where
+ fromInteger n = C (fromIntegral n,0.0)
+ C (x,y) * C (z,t) = C (z*x - y*t, y*z + x*t)
+ C (x,y) + C (z,t) = C (x+z, y+t)
+ abs (C (x,y)) = C (sqrt (x*x + y*y),0.0)
+ signum (C (x,y)) = C (signum x , 0.0)
+
+real :: Complex -> Float
+real (C (x,y)) = x
+im :: Complex -> Float
+im (C (x,y)) = y
+
+cabs :: Complex -> Float
+cabs = real.abs
+
+f :: Complex -> Complex -> Int -> Int
+f c z 0 = 0
+f c z n = if (cabs z > 2) then n else f c ((z*z)+c) (n-1)
+
+bmandel bottomleft topright = map (\z -> (f (C z) (C(0,0)) 32, (fst z > right - hstep/2 ))) [(x,y) | y <- [bottom,(bottom + vstep)..top], x<-[left,(left + hstep)..right]]
+ where
+ top = im topright
+ bottom = im bottomleft
+ left = real bottomleft
+ right = real topright
+ vstep=(top-bottom)/nbvert
+ hstep=(right-left)/nbhor
+
+mandel :: (Complex,Complex) -> String
+mandel (bottomleft,topright) = concat $ map treat $ bmandel bottomleft topright
+ where
+ treat (i,jump) = " .,:;rcuowijlbCUOW&$@#" !! (div (i*22) 32):rst jump
+ rst True = "\n"
+ rst False = ""
+
+cdiv :: Complex -> Float -> Complex
+cdiv (C(x,y)) r = C(x/r, y/r)
+cmul :: Complex -> Float -> Complex
+cmul (C(x,y)) r = C(x*r, y*r)
+
+zoom :: Complex -> Complex -> Complex -> Float -> (Complex,Complex)
+zoom bl tr center magn = (f bl, f tr)
+ where
+ f point = ((center `cmul` magn) + point ) `cdiv` (magn + 1)
+
+main = do
+ x <- getContents
+ putStrLn $ infinitemandel 0
+ where
+ window n = zoom init_bottom_left init_top_right interrest (zoomfactor**n)
+ infinitemandel n = mandel (window n) ++ "\x1b[H\x1b[25A" ++ infinitemandel (n+1)
+
+
+
+
+
+
+
+ Published on 2011-07-10
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+positivePoints =
+ for all x in the range [-width..width]
+ let y be smallest number s.t. mandel x y > 0
+ if y is on 0 then don't return a point
+ else return the value corresonding to (x,y,color for (x+iy))
+
+
+In fact using the list monad you write like if you consider only one element at a time and the computation is done non deterministically.
+To find the smallest number such that `mandel x y > 0` we use a simple dichotomy:
+
+> -- given f min max nbtest,
+> -- considering
+> -- - f is an increasing function
+> -- - f(min)=0
+> -- - f(max)≠0
+> -- then maxZeroIndex f min max nbtest returns x such that
+> -- f(x - ε)=0 and f(x + ε)≠0
+> -- where ε=(max-min)/2^(nbtest+1)
+> maxZeroIndex func minval maxval 0 = (minval+maxval)/2
+> maxZeroIndex func minval maxval n =
+> if (func medpoint) /= 0
+> then maxZeroIndex func minval medpoint (n-1)
+> else maxZeroIndex func medpoint maxval (n-1)
+> where medpoint = (minval+maxval)/2
+
+No rocket science here. See the result now:
+
+blogimage("HGLMandelEdges.png","The edges of the mandelbrot set")
+
+
+
diff --git a/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/03_Mandelbulb/Mandelbulb.lhs b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/03_Mandelbulb/Mandelbulb.lhs
new file mode 100644
index 0000000..fc20dc0
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/03_Mandelbulb/Mandelbulb.lhs
@@ -0,0 +1,378 @@
+ ## 3D Mandelbrot?
+
+Now we will we extend to a third dimension.
+But, there is no 3D equivalent to complex.
+In fact, the only extension known are quaternions (in 4D).
+As I know almost nothing about quaternions, I will use some extended complex,
+instead of using a 3D projection of quaternions.
+I am pretty sure this construction is not useful for numbers.
+But it will be enough for us to create something that look nice.
+
+This section is quite long, but don't be afraid,
+most of the code is some OpenGL boilerplate.
+If you just want to skim this section,
+here is a high level representation:
+
+ > - OpenGL Boilerplate
+ >
+ > - set some IORef (understand variables) for states
+ > - Drawing:
+ >
+ > - set doubleBuffer, handle depth, window size...
+ > - Use state to apply some transformations
+ >
+ > - Keyboard: hitting some key change the state of IORef
+ >
+ > - Generate 3D Object
+ >
+ > ~~~
+ > allPoints :: [ColoredPoint]
+ > allPoints =
+ > for all (x,y), -width
+depthPoints :: [ColoredPoint]
+depthPoints = do
+ x <- [-width..width]
+ y <- [-height..height]
+ let
+ depthOf x' y' = maxZeroIndex (mandel x' y') 0 deep logdeep
+ logdeep = floor ((log deep) / log 2)
+ z1 = depthOf x y
+ z2 = depthOf (x+1) y
+ z3 = depthOf (x+1) (y+1)
+ z4 = depthOf x (y+1)
+ c1 = mandel x y (z1+1)
+ c2 = mandel (x+1) y (z2+1)
+ c3 = mandel (x+1) (y+1) (z3+1)
+ c4 = mandel x (y+1) (z4+1)
+ p1 = ( x /width, y /height, z1/deep, colorFromValue c1)
+ p2 = ((x+1)/width, y /height, z2/deep, colorFromValue c2)
+ p3 = ((x+1)/width,(y+1)/height, z3/deep, colorFromValue c3)
+ p4 = ( x /width,(y+1)/height, z4/deep, colorFromValue c4)
+ if (and $ map (>=57) [c1,c2,c3,c4])
+ then []
+ else [p1,p2,p3,p1,p3,p4]
+
+
+If you look at the function above, you see a lot of common patterns.
+Haskell is very efficient to make this better.
+Here is a harder to read but shorter and more generic rewritten function:
+
+> depthPoints :: [ColoredPoint]
+> depthPoints = do
+> x <- [-width..width]
+> y <- [-height..height]
+> let
+> neighbors = [(x,y),(x+1,y),(x+1,y+1),(x,y+1)]
+> depthOf (u,v) = maxZeroIndex (mandel u v) 0 deep logdeep
+> logdeep = floor ((log deep) / log 2)
+> -- zs are 3D points with found depth
+> zs = map (\(u,v) -> (u,v,depthOf (u,v))) neighbors
+> -- ts are 3D pixels + mandel value
+> ts = map (\(u,v,w) -> (u,v,w,mandel u v (w+1))) zs
+> -- ps are 3D opengl points + color value
+> ps = map (\(u,v,w,c') ->
+> (u/width,v/height,w/deep,colorFromValue c')) ts
+> -- If the point diverged too fast, don't display it
+> if (and $ map (\(_,_,_,c) -> c>=57) ts)
+> then []
+> -- Draw two triangles
+> else [ps!!0,ps!!1,ps!!2,ps!!0,ps!!2,ps!!3]
+
+If you prefer the first version, then just imagine how hard it will be to change the enumeration of the point from (x,y) to (x,z) for example.
+
+Also, we didn't searched for negative values.
+This modified Mandelbrot is no more symmetric relatively to the plan `y=0`.
+But it is symmetric relatively to the plan `z=0`.
+Then I mirror these values.
+
+> allPoints :: [ColoredPoint]
+> allPoints = planPoints ++ map inverseDepth planPoints
+> where
+> planPoints = depthPoints
+> inverseDepth (x,y,z,c) = (x,y,-z+1/deep,c)
+
+The rest of the program is very close to the preceding one.
+
+
+
+We simply add a new dimension to the `mandel` function
+and change the type signature of `f` from `Complex` to `ExtComplex`.
+
+> mandel x y z =
+> let r = 2.0 * x / width
+> i = 2.0 * y / height
+> s = 2.0 * z / deep
+> in
+> f (extcomplex r i s) 0 64
+
+
+Here is the result:
+
+blogimage("mandelbrot_3D.png","A 3D mandelbrot like")
diff --git a/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/04_Mandelbulb/ExtComplex.hs b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/04_Mandelbulb/ExtComplex.hs
new file mode 100644
index 0000000..caba8d0
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/04_Mandelbulb/ExtComplex.hs
@@ -0,0 +1,37 @@
+module ExtComplex where
+
+import Graphics.Rendering.OpenGL
+
+-- This time I use unpacked strict data type
+-- Far faster when compiled.
+data ExtComplex = C {-# UNPACK #-} !GLfloat
+ {-# UNPACK #-} !GLfloat
+ {-# UNPACK #-} !GLfloat
+ deriving (Show,Eq)
+
+instance Num ExtComplex where
+ -- The shape of the 3D mandelbrot
+ -- will depend on this formula
+ (C x y z) * (C x' y' z') = C (x*x' - y*y' - z*z')
+ (x*y' + y*x' + z*z')
+ (x*z' + z*x' )
+ -- The rest is straightforward
+ fromInteger n = C (fromIntegral n) 0 0
+ (C x y z) + (C x' y' z') = C (x+x') (y+y') (z+z')
+ abs (C x y z) = C (sqrt (x*x + y*y + z*z)) 0 0
+ signum (C x y z) = C (signum x) (signum y) (signum z)
+
+extcomplex :: GLfloat -> GLfloat -> GLfloat -> ExtComplex
+extcomplex x y z = C x y z
+
+real :: ExtComplex -> GLfloat
+real (C x _ _) = x
+
+im :: ExtComplex -> GLfloat
+im (C _ y _) = y
+
+strange :: ExtComplex -> GLfloat
+strange (C _ _ z) = z
+
+magnitude :: ExtComplex -> GLfloat
+magnitude = real.abs
diff --git a/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/04_Mandelbulb/Mandel.hs b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/04_Mandelbulb/Mandel.hs
new file mode 100644
index 0000000..9500e0b
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/04_Mandelbulb/Mandel.hs
@@ -0,0 +1,13 @@
+-- The Mandelbrot function
+module Mandel (mandel) where
+
+import ExtComplex
+
+mandel r i s nbIterations =
+ f (extcomplex r i s) 0 nbIterations
+ where
+ f :: ExtComplex -> ExtComplex -> Int -> Int
+ f c z 0 = 0
+ f c z n = if (magnitude z > 2 )
+ then n
+ else f c ((z*z)+c) (n-1)
diff --git a/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/04_Mandelbulb/Mandelbulb.lhs b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/04_Mandelbulb/Mandelbulb.lhs
new file mode 100644
index 0000000..d9fb813
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/04_Mandelbulb/Mandelbulb.lhs
@@ -0,0 +1,90 @@
+ ## Naïve code cleaning
+
+The first approach to clean the code is to separate the GLUT/OpenGL
+part from the computation of the shape.
+Here is the cleaned version of the preceding section.
+Most boilerplate was put in external files.
+
+- [`YBoiler.hs`](code/04_Mandelbulb/YBoiler.hs), the 3D rendering
+- [`Mandel`](code/04_Mandelbulb/Mandel.hs), the mandel function
+- [`ExtComplex`](code/04_Mandelbulb/ExtComplex.hs), the extended complexes
+
+> import YBoiler -- Most the OpenGL Boilerplate
+> import Mandel -- The 3D Mandelbrot maths
+
+The `yMainLoop` takes two arguments:
+the title of the window
+and a function from time to triangles
+
+> main :: IO ()
+> main = yMainLoop "3D Mandelbrot" (\_ -> allPoints)
+
+We set some global constant (this is generally bad).
+
+> nbDetails = 200 :: GLfloat
+> width = nbDetails
+> height = nbDetails
+> deep = nbDetails
+
+We then generate colored points from our function.
+This is similar to the preceding section.
+
+> allPoints :: [ColoredPoint]
+> allPoints = planPoints ++ map inverseDepth planPoints
+> where
+> planPoints = depthPoints ++ map inverseHeight depthPoints
+> inverseHeight (x,y,z,c) = (x,-y,z,c)
+> inverseDepth (x,y,z,c) = (x,y,-z+1/deep,c)
+
+> depthPoints :: [ColoredPoint]
+> depthPoints = do
+> x <- [-width..width]
+> y <- [0..height]
+> let
+> neighbors = [(x,y),(x+1,y),(x+1,y+1),(x,y+1)]
+> depthOf (u,v) = maxZeroIndex (ymandel u v) 0 deep 7
+> -- zs are 3D points with found depth
+> zs = map (\(u,v) -> (u,v,depthOf (u,v))) neighbors
+> -- ts are 3D pixels + mandel value
+> ts = map (\(u,v,w) -> (u,v,w,ymandel u v (w+1))) zs
+> -- ps are 3D opengl points + color value
+> ps = map (\(u,v,w,c') ->
+> (u/width,v/height,w/deep,colorFromValue c')) ts
+> -- If the point diverged too fast, don't display it
+> if (and $ map (\(_,_,_,c) -> c>=57) ts)
+> then []
+> -- Draw two triangles
+> else [ps!!0,ps!!1,ps!!2,ps!!0,ps!!2,ps!!3]
+>
+>
+> -- given f min max nbtest,
+> -- considering
+> -- - f is an increasing function
+> -- - f(min)=0
+> -- - f(max)≠0
+> -- then maxZeroIndex f min max nbtest returns x such that
+> -- f(x - ε)=0 and f(x + ε)≠0
+> -- where ε=(max-min)/2^(nbtest+1)
+> maxZeroIndex func minval maxval 0 = (minval+maxval)/2
+> maxZeroIndex func minval maxval n =
+> if (func medpoint) /= 0
+> then maxZeroIndex func minval medpoint (n-1)
+> else maxZeroIndex func medpoint maxval (n-1)
+> where medpoint = (minval+maxval)/2
+>
+> colorFromValue n =
+> let
+> t :: Int -> GLfloat
+> t i = 0.7 + 0.3*cos( fromIntegral i / 10 )
+> in
+> ((t n),(t (n+5)),(t (n+10)))
+>
+> ymandel x y z = mandel (2*x/width) (2*y/height) (2*z/deep) 64
+
+This code is cleaner but many things doesn't feel right.
+First, all the user interaction code is outside our main file.
+I feel it is okay to hide the detail for the rendering.
+But I would have preferred to control the user actions.
+
+On the other hand, we continue to handle a lot rendering details.
+For example, we provide ordered vertices.
diff --git a/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/04_Mandelbulb/YBoiler.hs b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/04_Mandelbulb/YBoiler.hs
new file mode 100644
index 0000000..867f8b7
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/04_Mandelbulb/YBoiler.hs
@@ -0,0 +1,120 @@
+-- An OpenGL boilerplate
+module YBoiler (GLfloat,yMainLoop,ColoredPoint,Color3) where
+
+import Graphics.Rendering.OpenGL
+import Graphics.UI.GLUT
+import Data.IORef
+
+
+type ColorRGB = (GLfloat,GLfloat,GLfloat)
+type YAngle = (GLfloat,GLfloat,GLfloat)
+type ColoredPoint = (GLfloat,GLfloat,GLfloat,ColorRGB)
+
+yMainLoop :: String -> (Int -> [ColoredPoint]) -> IO ()
+yMainLoop windowTitle triangles = do
+ -- GLUT need to be initialized
+ (progname,_) <- getArgsAndInitialize
+ -- We will use the double buffered mode (GL constraint)
+ -- We also Add the DepthBuffer (for 3D)
+ initialDisplayMode $=
+ [WithDepthBuffer,DoubleBuffered,RGBMode]
+ -- We create a window with some title
+ createWindow windowTitle
+ -- We add some directives
+ depthFunc $= Just Less
+ -- matrixMode $= Projection
+ windowSize $= Size 500 500
+ -- Some state variables (I know it feels BAD)
+ angle <- newIORef ((35,0,0)::YAngle)
+ zoom <- newIORef (2::GLfloat)
+ campos <- newIORef ((0.7,0)::(GLfloat,GLfloat))
+ -- Action to call when waiting
+ idleCallback $= Just idle
+ -- We will use the keyboard
+ keyboardMouseCallback $=
+ Just (keyboardMouse angle zoom campos)
+ -- Each time we will need to update the display
+ -- we will call the function 'display'
+ -- But this time, we add some parameters
+ displayCallback $= display angle zoom campos triangles
+ -- We enter the main loop
+ mainLoop
+
+idle = postRedisplay Nothing
+
+-- modify IORef cleanly
+modVar :: IORef a -> (a -> a) -> IO ()
+modVar v f = do
+ v' <- get v
+ v $= (f v')
+-- modify IORef (a,b) using f:a->a
+mapFst f (x,y) = (f x, y)
+-- modify IORef (a,b) using f:b->b
+mapSnd f (x,y) = ( x,f y)
+mapFst3 f (x,y,z) = (f x, y, z)
+mapSnd3 f (x,y,z) = (x, f y, z)
+mapThi3 f (x,y,z) = (x, y, f z)
+
+-- Get User Input
+keyboardMouse angle zoom pos key state modifiers position =
+ kact angle zoom pos key state
+ where
+ -- reset view when hitting space
+ kact a z p (Char ' ') Down = do
+ a $= (0,0,0)
+ z $= 1
+ p $= (0,0)
+ -- use of hjkl to rotate
+ kact a _ _ (Char 'j') Down = modVar a (mapFst3 (+0.5))
+ kact a _ _ (Char 'l') Down = modVar a (mapFst3 (+(-0.5)))
+ kact a _ _ (Char 'i') Down = modVar a (mapSnd3 (+0.5))
+ kact a _ _ (Char 'k') Down = modVar a (mapSnd3 (+(-0.5)))
+ kact a _ _ (Char 'o') Down = modVar a (mapThi3 (+0.5))
+ kact a _ _ (Char 'u') Down = modVar a (mapThi3 (+(-0.5)))
+ -- use o and i to zoom
+ kact _ s _ (Char '+') Down = modVar s (*1.1)
+ kact _ s _ (Char '-') Down = modVar s (*0.9)
+ -- use sdfe to move the camera
+ kact _ _ p (Char 's') Down = modVar p (mapFst (+0.1))
+ kact _ _ p (Char 'f') Down = modVar p (mapFst (+(-0.1)))
+ kact _ _ p (Char 'd') Down = modVar p (mapSnd (+0.1))
+ kact _ _ p (Char 'e') Down = modVar p (mapSnd (+(-0.1)))
+ -- any other keys does nothing
+ kact _ _ _ _ _ = return ()
+
+-- The function that will display datas
+display angle zoom position triangles = do
+ -- set the background color (dark solarized theme)
+ clearColor $= Color4 0 0.1686 0.2117 1
+ clear [ColorBuffer,DepthBuffer]
+ -- Transformation to change the view
+ loadIdentity -- reset any transformation
+ -- tranlate
+ (x,y) <- get position
+ translate $ Vector3 x y 0
+ -- zoom
+ z <- get zoom
+ scale z z z
+ -- rotate
+ (xangle,yangle,zangle) <- get angle
+ rotate xangle $ Vector3 1.0 0.0 (0.0::GLfloat)
+ rotate yangle $ Vector3 0.0 1.0 (0.0::GLfloat)
+ rotate zangle $ Vector3 0.0 0.0 (1.0::GLfloat)
+ -- Now that all transformation were made
+ -- We create the object(s)
+ t <- get elapsedTime
+ preservingMatrix $ drawObject (triangles t)
+ swapBuffers -- refresh screen
+
+red (r,_,_) = r
+green (_,g,_) = g
+blue (_,_,b) = b
+
+drawObject triangles = do
+ -- We will print Points (not triangles for example)
+ renderPrimitive Triangles $ do
+ mapM_ drawColoredPoint triangles
+ where
+ drawColoredPoint (x,y,z,c) = do
+ color $ Color3 (red c) (green c) (blue c)
+ vertex $ Vertex3 x y z
diff --git a/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/05_Mandelbulb/ExtComplex.hs b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/05_Mandelbulb/ExtComplex.hs
new file mode 100644
index 0000000..caba8d0
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/05_Mandelbulb/ExtComplex.hs
@@ -0,0 +1,37 @@
+module ExtComplex where
+
+import Graphics.Rendering.OpenGL
+
+-- This time I use unpacked strict data type
+-- Far faster when compiled.
+data ExtComplex = C {-# UNPACK #-} !GLfloat
+ {-# UNPACK #-} !GLfloat
+ {-# UNPACK #-} !GLfloat
+ deriving (Show,Eq)
+
+instance Num ExtComplex where
+ -- The shape of the 3D mandelbrot
+ -- will depend on this formula
+ (C x y z) * (C x' y' z') = C (x*x' - y*y' - z*z')
+ (x*y' + y*x' + z*z')
+ (x*z' + z*x' )
+ -- The rest is straightforward
+ fromInteger n = C (fromIntegral n) 0 0
+ (C x y z) + (C x' y' z') = C (x+x') (y+y') (z+z')
+ abs (C x y z) = C (sqrt (x*x + y*y + z*z)) 0 0
+ signum (C x y z) = C (signum x) (signum y) (signum z)
+
+extcomplex :: GLfloat -> GLfloat -> GLfloat -> ExtComplex
+extcomplex x y z = C x y z
+
+real :: ExtComplex -> GLfloat
+real (C x _ _) = x
+
+im :: ExtComplex -> GLfloat
+im (C _ y _) = y
+
+strange :: ExtComplex -> GLfloat
+strange (C _ _ z) = z
+
+magnitude :: ExtComplex -> GLfloat
+magnitude = real.abs
diff --git a/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/05_Mandelbulb/Mandel.hs b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/05_Mandelbulb/Mandel.hs
new file mode 100644
index 0000000..7c1ef34
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/05_Mandelbulb/Mandel.hs
@@ -0,0 +1,14 @@
+-- The Mandelbrot function
+module Mandel (mandel) where
+
+import ExtComplex
+
+mandel :: Float -> Float -> Float -> Int -> Int
+mandel r i s nbIterations =
+ f (extcomplex r i s) 0 nbIterations
+ where
+ f :: ExtComplex -> ExtComplex -> Int -> Int
+ f _ _ 0 = 0
+ f c z n = if (magnitude z > 2 )
+ then n
+ else f c ((z*z)+c) (n-1)
diff --git a/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/05_Mandelbulb/Mandelbulb.lhs b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/05_Mandelbulb/Mandelbulb.lhs
new file mode 100644
index 0000000..f58abff
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/05_Mandelbulb/Mandelbulb.lhs
@@ -0,0 +1,250 @@
+ ## Functional organization?
+
+Some points:
+
+1. OpenGL and GLUT is done in C.
+ In particular the `mainLoop` function is a direct link to the C library (FFI).
+ This function is clearly far from the functional paradigm.
+ Could we make this better?
+ We will have two choices:
+
+ - create our own `mainLoop` function to make it more functional.
+ - deal with the imperative nature of the GLUT `mainLoop` function.
+
+ As one of the goal of this article is to understand how to deal with existing libraries and particularly the one coming from imperative languages, we will continue to use the `mainLoop` function.
+2. Our main problem come from user interaction.
+ If you ask "the Internet",
+ about how to deal with user interaction with a functional paradigm,
+ the main answer is to use _functional reactive programming_ (FRP).
+ I won't use FRP in this article.
+ Instead, I'll use a simpler while less effective way to deal with user interaction.
+ But The method I'll use will be as pure and functional as possible.
+
+Here is how I imagine things should go.
+First, what the main loop should look like if we could make our own:
+
+
+functionalMainLoop =
+ Read user inputs and provide a list of actions
+ Apply all actions to the World
+ Display one frame
+ repetere aeternum
+
+
+Clearly, ideally we should provide only three parameters to this main loop function:
+
+- an initial World state
+- a mapping between the user interactions and functions which modify the world
+- a function taking two parameters: time and world state and render a new world without user interaction.
+
+Here is a real working code, I've hidden most display functions.
+The YGL, is a kind of framework to display 3D functions.
+But it can easily be extended to many kind of representation.
+
+> import YGL -- Most the OpenGL Boilerplate
+> import Mandel -- The 3D Mandelbrot maths
+
+We first set the mapping between user input and actions.
+The type of each couple should be of the form
+`(user input, f)` where (in a first time) `f:World -> World`.
+It means, the user input will transform the world state.
+
+> -- Centralize all user input interaction
+> inputActionMap :: InputMap World
+> inputActionMap = inputMapFromList [
+> (Press 'k' , rotate xdir 5)
+> ,(Press 'i' , rotate xdir (-5))
+> ,(Press 'j' , rotate ydir 5)
+> ,(Press 'l' , rotate ydir (-5))
+> ,(Press 'o' , rotate zdir 5)
+> ,(Press 'u' , rotate zdir (-5))
+> ,(Press 'f' , translate xdir 0.1)
+> ,(Press 's' , translate xdir (-0.1))
+> ,(Press 'e' , translate ydir 0.1)
+> ,(Press 'd' , translate ydir (-0.1))
+> ,(Press 'z' , translate zdir 0.1)
+> ,(Press 'r' , translate zdir (-0.1))
+> ,(Press '+' , zoom 1.1)
+> ,(Press '-' , zoom (1/1.1))
+> ,(Press 'h' , resize 1.2)
+> ,(Press 'g' , resize (1/1.2))
+> ]
+
+And of course a type design the World State.
+The important part is that it is our World State type.
+We could have used any kind of data type.
+
+> -- I prefer to set my own name for these types
+> data World = World {
+> angle :: Point3D
+> , scale :: Scalar
+> , position :: Point3D
+> , shape :: Scalar -> Function3D
+> , box :: Box3D
+> , told :: Time -- last frame time
+> }
+
+The important part to glue our own type to the framework
+is to make our type an instance of the type class `DisplayableWorld`.
+We simply have to provide the definition of some functions.
+
+> instance DisplayableWorld World where
+> winTitle _ = "The YGL Mandelbulb"
+> camera w = Camera {
+> camPos = position w,
+> camDir = angle w,
+> camZoom = scale w }
+> -- objects for world w
+> -- is the list of one unique element
+> -- The element is an YObject
+> -- more precisely the XYFunc Function3D Box3D
+> -- where the Function3D is the type
+> -- Point -> Point -> Maybe (Point,Color)
+> -- and its value here is ((shape w) res)
+> -- and the Box3D value is defbox
+> objects w = [XYFunc ((shape w) res) defbox]
+> where
+> res = resolution $ box w
+> defbox = box w
+
+The `camera` function will retrieve an object of type `Camera` which contains
+most necessary information to set our camera.
+The `objects` function will returns a list of objects.
+Their type is `YObject`. Note the generation of triangles is no more in this file.
+Until here we only used declarative pattern.
+
+We also need to set all our transformation functions.
+These function are used to update the world state.
+
+> xdir :: Point3D
+> xdir = makePoint3D (1,0,0)
+> ydir :: Point3D
+> ydir = makePoint3D (0,1,0)
+> zdir :: Point3D
+> zdir = makePoint3D (0,0,1)
+
+Note `(-*<)` is the scalar product (`α -*< (x,y,z) = (αx,αy,αz)`).
+Also note we could add two Point3D.
+
+> rotate :: Point3D -> Scalar -> World -> World
+> rotate dir angleValue world =
+> world {
+> angle = (angle world) + (angleValue -*< dir) }
+>
+> translate :: Point3D -> Scalar -> World -> World
+> translate dir len world =
+> world {
+> position = (position world) + (len -*< dir) }
+>
+> zoom :: Scalar -> World -> World
+> zoom z world = world {
+> scale = z * scale world }
+>
+> resize :: Scalar -> World -> World
+> resize r world = world {
+> box = (box world) {
+> resolution = sqrt ((resolution (box world))**2 * r) }}
+
+The resize is used to generate the 3D function.
+As I wanted the time spent to generate a more detailed view
+to grow linearly I use this not so straightforward formula.
+
+The `yMainLoop` takes three arguments.
+
+- A map between user Input and world transformation
+- A timed world transformation
+- An initial world state
+
+> main :: IO ()
+> main = yMainLoop inputActionMap idleAction initialWorld
+
+Here is our initial world state.
+
+> -- We initialize the world state
+> -- then angle, position and zoom of the camera
+> -- And the shape function
+> initialWorld :: World
+> initialWorld = World {
+> angle = makePoint3D (-30,-30,0)
+> , position = makePoint3D (0,0,0)
+> , scale = 0.8
+> , shape = shapeFunc
+> , box = Box3D { minPoint = makePoint3D (-2,-2,-2)
+> , maxPoint = makePoint3D (2,2,2)
+> , resolution = 0.16 }
+> , told = 0
+> }
+
+We will define `shapeFunc` later.
+Here is the function which transform the world even without user action.
+Mainly it makes some rotation.
+
+> idleAction :: Time -> World -> World
+> idleAction tnew world = world {
+> angle = (angle world) + (delta -*< zdir)
+> , told = tnew
+> }
+> where
+> anglePerSec = 5.0
+> delta = anglePerSec * elapsed / 1000.0
+> elapsed = fromIntegral (tnew - (told world))
+
+Now the function which will generate points in 3D.
+The first parameter (`res`) is the resolution of the vertex generation.
+More precisely, `res` is distance between two points on one direction.
+We need it to "close" our shape.
+
+The type `Function3D` is `Point -> Point -> Maybe Point`.
+Because we consider partial functions
+(for some `(x,y)` our function can be undefined).
+
+> shapeFunc :: Scalar -> Function3D
+> shapeFunc res x y =
+> let
+> z = maxZeroIndex (ymandel x y) 0 1 20
+> in
+> if and [ maxZeroIndex (ymandel (x+xeps) (y+yeps)) 0 1 20 < 0.000001 |
+> val <- [res], xeps <- [-val,val], yeps<-[-val,val]]
+> then Nothing
+> else Just (z,colorFromValue ((ymandel x y z) * 64))
+
+With the color function.
+
+> colorFromValue :: Point -> Color
+> colorFromValue n =
+> let
+> t :: Point -> Scalar
+> t i = 0.7 + 0.3*cos( i / 10 )
+> in
+> makeColor (t n) (t (n+5)) (t (n+10))
+
+The rest is similar to the preceding sections.
+
+> -- given f min max nbtest,
+> -- considering
+> -- - f is an increasing function
+> -- - f(min)=0
+> -- - f(max)≠0
+> -- then maxZeroIndex f min max nbtest returns x such that
+> -- f(x - ε)=0 and f(x + ε)≠0
+> -- where ε=(max-min)/2^(nbtest+1)
+> maxZeroIndex :: (Fractional a,Num a,Num b,Eq b) =>
+> (a -> b) -> a -> a -> Int -> a
+> maxZeroIndex _ minval maxval 0 = (minval+maxval)/2
+> maxZeroIndex func minval maxval n =
+> if (func medpoint) /= 0
+> then maxZeroIndex func minval medpoint (n-1)
+> else maxZeroIndex func medpoint maxval (n-1)
+> where medpoint = (minval+maxval)/2
+>
+> ymandel :: Point -> Point -> Point -> Point
+> ymandel x y z = fromIntegral (mandel x y z 64) / 64
+
+I won't explain how the magic occurs here.
+If you are interested, just read the file [`YGL.hs`](code/05_Mandelbulb/YGL.hs).
+It is commented a lot.
+
+- [`YGL.hs`](code/05_Mandelbulb/YGL.hs), the 3D rendering framework
+- [`Mandel`](code/05_Mandelbulb/Mandel.hs), the mandel function
+- [`ExtComplex`](code/05_Mandelbulb/ExtComplex.hs), the extended complexes
+
diff --git a/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/05_Mandelbulb/YGL.hs b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/05_Mandelbulb/YGL.hs
new file mode 100644
index 0000000..2f6e166
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/05_Mandelbulb/YGL.hs
@@ -0,0 +1,383 @@
+{-
+The module YGL will contains most boilerplate
+And display details.
+
+To make things even nicer, we should separate
+this file in many different parts.
+Typically separate the display function.
+
+-}
+module YGL (
+ -- Here is declared our interface with external files
+ -- that will include our YGL module
+
+ -- Declarations related to data types
+ Point -- the 1 dimension point type
+ , Time -- the type for the time
+ , Scalar -- the type for scalar values
+ , Color -- the type for color (3 scalars)
+ , Point3D (..) -- A 3D point type (3 Points)
+ , makePoint3D -- helper (x,y,z) -> Point3D
+ , (-*<) -- scalar product on Point3D a -*< (x,y,z) = (ax,ay,az)
+ , Function3D -- Point -> Point -> Maybe (Point,Color)
+
+ -- Your world state must be an instance
+ -- of the DisplayableWorld type class
+ , DisplayableWorld (..)
+ -- Datas related to DisplayableWorld
+ , Camera (..)
+ , YObject (..) -- 3D Objects to display
+ , Box3D (..) -- Some bounded 3D box
+ , makeBox -- helper to make a box
+ , hexColor -- Color from hexadecimal string
+ , makeColor -- make color from RGB values
+ -- Interface related to user input
+ , InputMap
+ , UserInput (Press,Ctrl,Alt,CtrlAlt)
+ , inputMapFromList
+
+ -- The main loop function to call
+ , yMainLoop
+) where
+
+-- A bunch of imports
+import Numeric (readHex) -- to read hexadecimal values
+
+-- Import of OpenGL and GLUT
+-- but, I use my own Color type, therefore I hide the definition
+-- of Color inside GLUT and OpenGL packages
+import Graphics.Rendering.OpenGL hiding (Color)
+import Graphics.UI.GLUT hiding (Color)
+import Data.IORef
+
+-- I use Map to deal with user interaction
+import qualified Data.Map as Map
+
+-- Some standard stuff
+import Control.Monad (when)
+import Data.Maybe (isNothing)
+
+{-- Things start to be complex here.
+- Just take the time to follow me.
+--}
+
+-- | A 1D point
+type Point = GLfloat
+-- | A Scalar value
+type Scalar = GLfloat
+-- | The time type (currently its Int)
+type Time = Int
+-- | A 3D Point mainly '(x,y,z)'
+data Point3D = P (Point,Point,Point) deriving (Eq,Show,Read)
+type Color = Color3 Scalar
+
+-- Get x (resp. y, z) coordinate of a 3D point
+xpoint :: Point3D -> Point
+xpoint (P (x,_,_)) = x
+ypoint :: Point3D -> Point
+ypoint (P (_,y,_)) = y
+zpoint :: Point3D -> Point
+zpoint (P (_,_,z)) = z
+
+-- Create a Point3D element from a triplet
+makePoint3D :: (Point,Point,Point) -> Point3D
+makePoint3D = P
+
+-- Make Point3D an instance of Num
+instance Num Point3D where
+ (+) (P (ax,ay,az)) (P (bx,by,bz)) = P (ax+bx,ay+by,az+bz)
+ (-) (P (ax,ay,az)) (P (bx,by,bz)) = P (ax-bx,ay-by,az-bz)
+ (*) (P (ax,ay,az)) (P (bx,by,bz)) = P ( ay*bz - az*by
+ , az*bx - ax*bz
+ , ax*by - ay*bx )
+ abs (P (x,y,z)) = P (abs x,abs y, abs z)
+ signum (P (x,y,z)) = P (signum x, signum y, signum z)
+ fromInteger i = P (fromInteger i, 0, 0)
+
+-- The scalar product
+infixr 5 -*<
+(-*<) :: Scalar -> Point3D -> Point3D
+(-*<) s p = P (s*xpoint p, s*ypoint p, s*zpoint p)
+
+-- Used internally to convert point3D to different types
+toGLVector3 :: Point3D -> Vector3 GLfloat
+toGLVector3 (P(x,y,z)) = Vector3 x y z
+
+toGLVertex3 :: Point3D -> Vertex3 GLfloat
+toGLVertex3 (P(x,y,z)) = Vertex3 x y z
+
+toGLNormal3 :: Point3D -> Normal3 GLfloat
+toGLNormal3 (P(x,y,z)) = Normal3 x y z
+
+-- | The Box3D type represent a 3D bounding box
+-- | Note if minPoint = (x,y,z) and maxPoint = (x',y',z')
+-- | Then to have a non empty box you must have
+-- | x
+Constant Function -> Constant List of Triangles -> Display
+
+
+Now we have
+
+
+Main loop -> World -> Function -> List of Objects -> Atoms -> Display
+
+
+The World state could change.
+The compiler can no more optimize the computation for us.
+We have to manually explain when to redraw the shape.
+
+To optimize we must do some things in a lower level.
+Mostly the program remains the same,
+but it will provide the list of atoms directly.
+
+
+
+> data World = World {
+> angle :: Point3D
+> , anglePerSec :: Scalar
+> , scale :: Scalar
+> , position :: Point3D
+> , box :: Box3D
+> , told :: Time
+> -- We replace shape by cache
+> , cache :: [YObject]
+> }
+
+
+> instance DisplayableWorld World where
+> winTitle _ = "The YGL Mandelbulb"
+> camera w = Camera {
+> camPos = position w,
+> camDir = angle w,
+> camZoom = scale w }
+> -- We update our objects instanciation
+> objects = cache
+
+
+
+Our initial world state is slightly changed:
+
+> -- We initialize the world state
+> -- then angle, position and zoom of the camera
+> -- And the shape function
+> initialWorld :: World
+> initialWorld = World {
+> angle = makePoint3D (30,30,0)
+> , anglePerSec = 5.0
+> , position = makePoint3D (0,0,0)
+> , scale = 1.0
+> , box = Box3D { minPoint = makePoint3D (0-eps, 0-eps, 0-eps)
+> , maxPoint = makePoint3D (0+eps, 0+eps, 0+eps)
+> , resolution = 0.02 }
+> , told = 0
+> -- We declare cache directly this time
+> , cache = objectFunctionFromWorld initialWorld
+> }
+> where eps=2
+
+The use of `eps` is a hint to make a better zoom by computing with the right bounds.
+
+We use the `YGL.getObject3DFromShapeFunction` function directly.
+This way instead of providing `XYFunc`, we provide directly a list of Atoms.
+
+> objectFunctionFromWorld :: World -> [YObject]
+> objectFunctionFromWorld w = [Atoms atomList]
+> where atomListPositive =
+> getObject3DFromShapeFunction
+> (shapeFunc (resolution (box w))) (box w)
+> atomList = atomListPositive ++
+> map negativeTriangle atomListPositive
+> negativeTriangle (ColoredTriangle (p1,p2,p3,c)) =
+> ColoredTriangle (negz p1,negz p3,negz p2,c)
+> where negz (P (x,y,z)) = P (x,y,-z)
+
+We know that resize is the only world change that necessitate to
+recompute the list of atoms (triangles).
+Then we update our world state accordingly.
+
+> resize :: Scalar -> World -> World
+> resize r world =
+> tmpWorld { cache = objectFunctionFromWorld tmpWorld }
+> where
+> tmpWorld = world { box = (box world) {
+> resolution = sqrt ((resolution (box world))**2 * r) }}
+
+All the rest is exactly the same.
+
+
+
+And you can also consider minor changes in the `YGL.hs` source file.
+
+- [`YGL.hs`](code/06_Mandelbulb/YGL.hs), the 3D rendering framework
+- [`Mandel`](code/06_Mandelbulb/Mandel.hs), the mandel function
+- [`ExtComplex`](code/06_Mandelbulb/ExtComplex.hs), the extended complexes
diff --git a/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/06_Mandelbulb/YGL.hs b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/06_Mandelbulb/YGL.hs
new file mode 100644
index 0000000..ee70ae7
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-OpenGL-Mandelbrot/code/06_Mandelbulb/YGL.hs
@@ -0,0 +1,385 @@
+{-
+The module YGL will contains most boilerplate
+And display details.
+
+To make things even nicer, we should separate
+this file in many different parts.
+Typically separate the display function.
+
+-}
+module YGL (
+ -- Here is declared our interface with external files
+ -- that will include our YGL module
+
+ -- Declarations related to data types
+ Point -- the 1 dimension point type
+ , Time -- the type for the time
+ , Scalar -- the type for scalar values
+ , Color -- the type for color (3 scalars)
+ , Point3D (..) -- A 3D point type (3 Points)
+ , makePoint3D -- helper (x,y,z) -> Point3D
+ , (-*<) -- scalar product on Point3D a -*< (x,y,z) = (ax,ay,az)
+ , Function3D -- Point -> Point -> Maybe (Point,Color)
+ , xpoint, ypoint, zpoint
+ , Atom (..) -- The Atom object (colored triangles for now)
+
+ -- Your world state must be an instance
+ -- of the DisplayableWorld type class
+ , DisplayableWorld (..)
+ -- Datas related to DisplayableWorld
+ , Camera (..)
+ , YObject (..) -- 3D Objects to display
+ , Box3D (..) -- Some bounded 3D box
+ , getObject3DFromShapeFunction
+ , makeBox -- helper to make a box
+ , hexColor -- Color from hexadecimal string
+ , makeColor -- make color from RGB values
+
+ -- Interface related to user input
+ , InputMap
+ , UserInput (Press,Ctrl,Alt,CtrlAlt)
+ , inputMapFromList
+
+ -- The main loop function to call
+ , yMainLoop
+) where
+
+-- A bunch of imports
+import Numeric (readHex) -- to read hexadecimal values
+
+-- Import of OpenGL and GLUT
+-- but, I use my own Color type, therefore I hide the definition
+-- of Color inside GLUT and OpenGL packages
+import Graphics.Rendering.OpenGL hiding (Color)
+import Graphics.UI.GLUT hiding (Color)
+import Data.IORef
+
+-- I use Map to deal with user interaction
+import qualified Data.Map as Map
+
+-- Some standard stuff
+import Control.Monad (when)
+import Data.Maybe (isNothing)
+
+{-- Things start to be complex here.
+- Just take the time to follow me.
+--}
+
+-- | A 1D point
+type Point = GLfloat
+-- | A Scalar value
+type Scalar = GLfloat
+-- | The time type (currently its Int)
+type Time = Int
+-- | A 3D Point mainly '(x,y,z)'
+data Point3D = P (Point,Point,Point) deriving (Eq,Show,Read)
+type Color = Color3 Scalar
+
+-- Get x (resp. y, z) coordinate of a 3D point
+xpoint :: Point3D -> Point
+xpoint (P (x,_,_)) = x
+ypoint :: Point3D -> Point
+ypoint (P (_,y,_)) = y
+zpoint :: Point3D -> Point
+zpoint (P (_,_,z)) = z
+
+-- Create a Point3D element from a triplet
+makePoint3D :: (Point,Point,Point) -> Point3D
+makePoint3D = P
+
+-- Make Point3D an instance of Num
+instance Num Point3D where
+ (+) (P (ax,ay,az)) (P (bx,by,bz)) = P (ax+bx,ay+by,az+bz)
+ (-) (P (ax,ay,az)) (P (bx,by,bz)) = P (ax-bx,ay-by,az-bz)
+ (*) (P (ax,ay,az)) (P (bx,by,bz)) = P ( ay*bz - az*by
+ , az*bx - ax*bz
+ , ax*by - ay*bx )
+ abs (P (x,y,z)) = P (abs x,abs y, abs z)
+ signum (P (x,y,z)) = P (signum x, signum y, signum z)
+ fromInteger i = P (fromInteger i, 0, 0)
+
+-- The scalar product
+infixr 5 -*<
+(-*<) :: Scalar -> Point3D -> Point3D
+(-*<) s p = P (s*xpoint p, s*ypoint p, s*zpoint p)
+
+-- Used internally to convert point3D to different types
+toGLVector3 :: Point3D -> Vector3 GLfloat
+toGLVector3 (P(x,y,z)) = Vector3 x y z
+
+toGLVertex3 :: Point3D -> Vertex3 GLfloat
+toGLVertex3 (P(x,y,z)) = Vertex3 x y z
+
+toGLNormal3 :: Point3D -> Normal3 GLfloat
+toGLNormal3 (P(x,y,z)) = Normal3 x y z
+
+-- | The Box3D type represent a 3D bounding box
+-- | Note if minPoint = (x,y,z) and maxPoint = (x',y',z')
+-- | Then to have a non empty box you must have
+-- | x
+
+
+
diff --git a/src/Scratch/en/blog/Haskell-Tutorials--a-tutorial/index.html b/src/Scratch/en/blog/Haskell-Tutorials--a-tutorial/index.html
new file mode 100644
index 0000000..3efb6d8
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-Tutorials--a-tutorial/index.html
@@ -0,0 +1,365 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Haskell Progressive Example
+ An OpenGL 3D extension of the Mandelbrot set
+
+
+
+
+
+
+
+
+
+
+
+Introduction
+IO).
+
+repa package1.
+
+
+
+
+
+
+First version
+Let’s play the song of our people
+
+Complex data type.
+
+
+
+
+
+Let us start
+
+
+
+main :: IO ()
+main = do
+ -- GLUT need to be initialized
+ (progname,_) <- getArgsAndInitialize
+ -- We will use the double buffered mode (GL constraint)
+ initialDisplayMode $= [DoubleBuffered]
+ -- We create a window with some title
+ createWindow "Mandelbrot Set with Haskell and OpenGL"
+ -- Each time we will need to update the display
+ -- we will call the function 'display'
+ displayCallback $= display
+ -- We enter the main loop
+ mainLoopdisplay will be used to render the graphics:
+
+
+drawMandelbrot.
+
+
+drawMandelbrot =
+ -- We will print Points (not triangles for example)
+ renderPrimitive Points $ do
+ mapM_ drawColoredPoint allPoints
+ where
+ drawColoredPoint (x,y,c) = do
+ color c -- set the current color to c
+ -- then draw the point at position (x,y,0)
+ -- remember we're in 3D
+ vertex $ Vertex3 x y 0mapM_ function is mainly the same as map but inside a monadic context. More precisely, this can be transformed as a list of actions where the order is important:
+drawMandelbrot =
+ renderPrimitive Points $ do
+ color color1
+ vertex $ Vertex3 x1 y1 0
+ ...
+ color colorN
+ vertex $ Vertex3 xN yN 0
+
+
+
+
+
+mandel function. Given two coordinates in pixels, it returns some integer value:
fc(z) = z2 + c
0 → fc(0) → fc(fc(0)) → ⋯ → fcn(0) → ⋯
+
+
+
+
+
+allPoints is a pure list. Therefore, calling allPoints will always render the same result and Haskell is clever enough to use this property. While Haskell doesn’t garbage collect allPoints the result is reused for free. We did not specified this value should be saved for later use. It is saved for us.
+
+
+
+Only the edges
+
+drawMandelbrot function. We replace the Points by LineLoop
+
+
+drawMandelbrot =
+ -- We will print Points (not triangles for example)
+ renderPrimitive LineLoop $ do
+ mapM_ drawColoredPoint allPoints
+ where
+ drawColoredPoint (x,y,c) = do
+ color c -- set the current color to c
+ -- then draw the point at position (x,y,0)
+ -- remember we're in 3D
+ vertex $ Vertex3 x y 0
+
+
+positivePoints :: [(GLfloat,GLfloat,Color3 GLfloat)]
+positivePoints = do
+ x <- [-width..width]
+ let y = maxZeroIndex (mandel x) 0 height (log2 height)
+ if y < 1 -- We don't draw point in the absciss
+ then []
+ else return (x/width,y/height,colorFromValue $ mandel x y)
+ where
+ log2 n = floor ((log n) / log 2)
+positivePoints =
+ for all x in the range [-width..width]
+ let y be smallest number s.t. mandel x y > 0
+ if y is on 0 then don't return a point
+ else return the value corresonding to (x,y,color for (x+iy))mandel x y > 0 we use a simple dichotomy:
+
+
+-- given f min max nbtest,
+-- considering
+-- - f is an increasing function
+-- - f(min)=0
+-- - f(max)≠0
+-- then maxZeroIndex f min max nbtest returns x such that
+-- f(x - ε)=0 and f(x + ε)≠0
+-- where ε=(max-min)/2^(nbtest+1)
+maxZeroIndex func minval maxval 0 = (minval+maxval)/2
+maxZeroIndex func minval maxval n =
+ if (func medpoint) /= 0
+ then maxZeroIndex func minval medpoint (n-1)
+ else maxZeroIndex func medpoint maxval (n-1)
+ where medpoint = (minval+maxval)/2
+
+
+
+
+3D Mandelbrot?
+
+
+
+
+
+
+
IORef (understand variables) for states
+
IORef
+
+
+ExtComplex (for extended complex). An extension of complex numbers with a third component:
+
+
+data ExtComplex = C GLfloat GLfloat GLfloat
+ deriving (Show,Eq)
+instance Num ExtComplex where
+ -- The shape of the 3D mandelbrot
+ -- will depend on this formula
+ (C x y z) * (C x' y' z') = C (x*x' - y*y' - z*z')
+ (x*y' + y*x' + z*z')
+ (x*z' + z*x')
+ -- The rest is straightforward
+ fromInteger n = C (fromIntegral n) 0 0
+ (C x y z) + (C x' y' z') = C (x+x') (y+y') (z+z')
+ abs (C x y z) = C (sqrt (x*x + y*y + z*z)) 0 0
+ signum (C x y z) = C (signum x) (signum y) (signum z)
real((x, y, z) × (x′, y′, z′)) = xx′ − yy′ − zz′
im((x, y, z) × (x′, y′, z′)) = xy′ − yx′ + zz′
strange((x, y, z) × (x′, y′, z′)) = xz′ + zx′From 2D to 3D
+
+
+
+main :: IO ()
+main = do
+ -- GLUT need to be initialized
+ (progname,_) <- getArgsAndInitialize
+ -- We will use the double buffered mode (GL constraint)
+ -- We also Add the DepthBuffer (for 3D)
+ initialDisplayMode $=
+ [WithDepthBuffer,DoubleBuffered,RGBMode]
+ -- We create a window with some title
+ createWindow "3D HOpengGL Mandelbrot"
+ -- We add some directives
+ depthFunc $= Just Less
+ windowSize $= Size 500 500
+ -- Some state variables (I know it feels BAD)
+ angle <- newIORef ((35,0)::(GLfloat,GLfloat))
+ zoom <- newIORef (2::GLfloat)
+ campos <- newIORef ((0.7,0)::(GLfloat,GLfloat))
+ -- Function to call each frame
+ idleCallback $= Just idle
+ -- Function to call when keyboard or mouse is used
+ keyboardMouseCallback $=
+ Just (keyboardMouse angle zoom campos)
+ -- Each time we will need to update the display
+ -- we will call the function 'display'
+ -- But this time, we add some parameters
+ displayCallback $= display angle zoom campos
+ -- We enter the main loop
+ mainLoopidle is here to change the states. There should never be any modification done in the display function.IORef. Mainly modVar x f is equivalent to the imperative x:=f(x), modFst (x,y) (+1) is equivalent to (x,y) := (x+1,y) and modSnd (x,y) (+1) is equivalent to (x,y) := (x,y+1)
+
+
+hjkl to rotate, oi to zoom and sedf to move. Also, hitting space will reset the view. Remember that angle and campos are pairs and zoom is a scalar. Also note (+0.5) is the function \x->x+0.5 and (-0.5) is the number -0.5 (yes I share your pain).
+
+
+keyboardMouse angle zoom campos key state modifiers position =
+ -- We won't use modifiers nor position
+ kact angle zoom campos key state
+ where
+ -- reset view when hitting space
+ kact a z p (Char ' ') Down = do
+ a $= (0,0) -- angle
+ z $= 1 -- zoom
+ p $= (0,0) -- camera position
+ -- use of hjkl to rotate
+ kact a _ _ (Char 'h') Down = modVar a (mapFst (+0.5))
+ kact a _ _ (Char 'l') Down = modVar a (mapFst (+(-0.5)))
+ kact a _ _ (Char 'j') Down = modVar a (mapSnd (+0.5))
+ kact a _ _ (Char 'k') Down = modVar a (mapSnd (+(-0.5)))
+ -- use o and i to zoom
+ kact _ z _ (Char 'o') Down = modVar z (*1.1)
+ kact _ z _ (Char 'i') Down = modVar z (*0.9)
+ -- use sdfe to move the camera
+ kact _ _ p (Char 's') Down = modVar p (mapFst (+0.1))
+ kact _ _ p (Char 'f') Down = modVar p (mapFst (+(-0.1)))
+ kact _ _ p (Char 'd') Down = modVar p (mapSnd (+0.1))
+ kact _ _ p (Char 'e') Down = modVar p (mapSnd (+(-0.1)))
+ -- any other keys does nothing
+ kact _ _ _ _ _ = return ()display takes some parameters this time. This function if full of boilerplate:
+
+
+display angle zoom position = do
+ -- set the background color (dark solarized theme)
+ clearColor $= Color4 0 0.1686 0.2117 1
+ clear [ColorBuffer,DepthBuffer]
+ -- Transformation to change the view
+ loadIdentity -- reset any transformation
+ -- tranlate
+ (x,y) <- get position
+ translate $ Vector3 x y 0
+ -- zoom
+ z <- get zoom
+ scale z z z
+ -- rotate
+ (xangle,yangle) <- get angle
+ rotate xangle $ Vector3 1.0 0.0 (0.0::GLfloat)
+ rotate yangle $ Vector3 0.0 1.0 (0.0::GLfloat)
+
+ -- Now that all transformation were made
+ -- We create the object(s)
+ preservingMatrix drawMandelbrot
+
+ swapBuffers -- refresh screenThe 3D Mandelbrot
+allPoints will provide a multiple of three points. Each three successive point representing the coordinate of each vertex of a triangle.
+
+
+
+
+
+
+forall x from -width to width
+ forall y from -height to height
+ forall the neighbors of (x,y)
+ let z be the smalled depth such that (mandel x y z)>0
+ let c be the color given by mandel x y z
+ add the point corresponding to (x,y,z,c)
+depthPoints :: [ColoredPoint]
+depthPoints = do
+ x <- [-width..width]
+ y <- [-height..height]
+ let
+ depthOf x' y' = maxZeroIndex (mandel x' y') 0 deep logdeep
+ logdeep = floor ((log deep) / log 2)
+ z1 = depthOf x y
+ z2 = depthOf (x+1) y
+ z3 = depthOf (x+1) (y+1)
+ z4 = depthOf x (y+1)
+ c1 = mandel x y (z1+1)
+ c2 = mandel (x+1) y (z2+1)
+ c3 = mandel (x+1) (y+1) (z3+1)
+ c4 = mandel x (y+1) (z4+1)
+ p1 = ( x /width, y /height, z1/deep, colorFromValue c1)
+ p2 = ((x+1)/width, y /height, z2/deep, colorFromValue c2)
+ p3 = ((x+1)/width,(y+1)/height, z3/deep, colorFromValue c3)
+ p4 = ( x /width,(y+1)/height, z4/deep, colorFromValue c4)
+ if (and $ map (>=57) [c1,c2,c3,c4])
+ then []
+ else [p1,p2,p3,p1,p3,p4]
+
+
+depthPoints :: [ColoredPoint]
+depthPoints = do
+ x <- [-width..width]
+ y <- [-height..height]
+ let
+ neighbors = [(x,y),(x+1,y),(x+1,y+1),(x,y+1)]
+ depthOf (u,v) = maxZeroIndex (mandel u v) 0 deep logdeep
+ logdeep = floor ((log deep) / log 2)
+ -- zs are 3D points with found depth
+ zs = map (\(u,v) -> (u,v,depthOf (u,v))) neighbors
+ -- ts are 3D pixels + mandel value
+ ts = map (\(u,v,w) -> (u,v,w,mandel u v (w+1))) zs
+ -- ps are 3D opengl points + color value
+ ps = map (\(u,v,w,c') ->
+ (u/width,v/height,w/deep,colorFromValue c')) ts
+ -- If the point diverged too fast, don't display it
+ if (and $ map (\(_,_,_,c) -> c>=57) ts)
+ then []
+ -- Draw two triangles
+ else [ps!!0,ps!!1,ps!!2,ps!!0,ps!!2,ps!!3]y=0. But it is symmetric relatively to the plan z=0. Then I mirror these values.
+
+
+mandel function and change the type signature of f from Complex to ExtComplex.
+
+
+
+
+
+
+Naïve code cleaning
+
+
+
+YBoiler.hs, the 3D renderingMandel, the mandel functionExtComplex, the extended complexesyMainLoop takes two arguments: the title of the window and a function from time to triangles
+
+
+
+
+
+depthPoints :: [ColoredPoint]
+depthPoints = do
+ x <- [-width..width]
+ y <- [0..height]
+ let
+ neighbors = [(x,y),(x+1,y),(x+1,y+1),(x,y+1)]
+ depthOf (u,v) = maxZeroIndex (ymandel u v) 0 deep 7
+ -- zs are 3D points with found depth
+ zs = map (\(u,v) -> (u,v,depthOf (u,v))) neighbors
+ -- ts are 3D pixels + mandel value
+ ts = map (\(u,v,w) -> (u,v,w,ymandel u v (w+1))) zs
+ -- ps are 3D opengl points + color value
+ ps = map (\(u,v,w,c') ->
+ (u/width,v/height,w/deep,colorFromValue c')) ts
+ -- If the point diverged too fast, don't display it
+ if (and $ map (\(_,_,_,c) -> c>=57) ts)
+ then []
+ -- Draw two triangles
+ else [ps!!0,ps!!1,ps!!2,ps!!0,ps!!2,ps!!3]
+
+-- given f min max nbtest,
+-- considering
+-- - f is an increasing function
+-- - f(min)=0
+-- - f(max)≠0
+-- then maxZeroIndex f min max nbtest returns x such that
+-- f(x - ε)=0 and f(x + ε)≠0
+-- where ε=(max-min)/2^(nbtest+1)
+maxZeroIndex func minval maxval 0 = (minval+maxval)/2
+maxZeroIndex func minval maxval n =
+ if (func medpoint) /= 0
+ then maxZeroIndex func minval medpoint (n-1)
+ else maxZeroIndex func medpoint maxval (n-1)
+ where medpoint = (minval+maxval)/2
+
+colorFromValue n =
+ let
+ t :: Int -> GLfloat
+ t i = 0.7 + 0.3*cos( fromIntegral i / 10 )
+ in
+ ((t n),(t (n+5)),(t (n+10)))
+
+ymandel x y z = mandel (2*x/width) (2*y/height) (2*z/deep) 64
+Functional organization?
+
+
+mainLoop function is a direct link to the C library (FFI). This function is clearly far from the functional paradigm. Could we make this better? We will have two choices:
+
+As one of the goal of this article is to understand how to deal with existing libraries and particularly the one coming from imperative languages, we will continue to use the mainLoop function to make it more functional.mainLoop function.mainLoop function.
+functionalMainLoop =
+ Read user inputs and provide a list of actions
+ Apply all actions to the World
+ Display one frame
+ repetere aeternum
+
+(user input, f) where (in a first time) f:World -> World. It means, the user input will transform the world state.
+
+
+-- Centralize all user input interaction
+inputActionMap :: InputMap World
+inputActionMap = inputMapFromList [
+ (Press 'k' , rotate xdir 5)
+ ,(Press 'i' , rotate xdir (-5))
+ ,(Press 'j' , rotate ydir 5)
+ ,(Press 'l' , rotate ydir (-5))
+ ,(Press 'o' , rotate zdir 5)
+ ,(Press 'u' , rotate zdir (-5))
+ ,(Press 'f' , translate xdir 0.1)
+ ,(Press 's' , translate xdir (-0.1))
+ ,(Press 'e' , translate ydir 0.1)
+ ,(Press 'd' , translate ydir (-0.1))
+ ,(Press 'z' , translate zdir 0.1)
+ ,(Press 'r' , translate zdir (-0.1))
+ ,(Press '+' , zoom 1.1)
+ ,(Press '-' , zoom (1/1.1))
+ ,(Press 'h' , resize 1.2)
+ ,(Press 'g' , resize (1/1.2))
+ ]
+
+
+DisplayableWorld. We simply have to provide the definition of some functions.
+
+
+instance DisplayableWorld World where
+ winTitle _ = "The YGL Mandelbulb"
+ camera w = Camera {
+ camPos = position w,
+ camDir = angle w,
+ camZoom = scale w }
+ -- objects for world w
+ -- is the list of one unique element
+ -- The element is an YObject
+ -- more precisely the XYFunc Function3D Box3D
+ -- where the Function3D is the type
+ -- Point -> Point -> Maybe (Point,Color)
+ -- and its value here is ((shape w) res)
+ -- and the Box3D value is defbox
+ objects w = [XYFunc ((shape w) res) defbox]
+ where
+ res = resolution $ box w
+ defbox = box wcamera function will retrieve an object of type Camera which contains most necessary information to set our camera. The objects function will returns a list of objects. Their type is YObject. Note the generation of triangles is no more in this file. Until here we only used declarative pattern.
+
+
+(-*<) is the scalar product (α -*< (x,y,z) = (αx,αy,αz)). Also note we could add two Point3D.
+
+
+rotate :: Point3D -> Scalar -> World -> World
+rotate dir angleValue world =
+ world {
+ angle = (angle world) + (angleValue -*< dir) }
+
+translate :: Point3D -> Scalar -> World -> World
+translate dir len world =
+ world {
+ position = (position world) + (len -*< dir) }
+
+zoom :: Scalar -> World -> World
+zoom z world = world {
+ scale = z * scale world }
+
+resize :: Scalar -> World -> World
+resize r world = world {
+ box = (box world) {
+ resolution = sqrt ((resolution (box world))**2 * r) }}yMainLoop takes three arguments.
+
+
+
+
+
+-- We initialize the world state
+-- then angle, position and zoom of the camera
+-- And the shape function
+initialWorld :: World
+initialWorld = World {
+ angle = makePoint3D (-30,-30,0)
+ , position = makePoint3D (0,0,0)
+ , scale = 0.8
+ , shape = shapeFunc
+ , box = Box3D { minPoint = makePoint3D (-2,-2,-2)
+ , maxPoint = makePoint3D (2,2,2)
+ , resolution = 0.16 }
+ , told = 0
+ }shapeFunc later. Here is the function which transform the world even without user action. Mainly it makes some rotation.
+
+
+res) is the resolution of the vertex generation. More precisely, res is distance between two points on one direction. We need it to “close” our shape.Function3D is Point -> Point -> Maybe Point. Because we consider partial functions (for some (x,y) our function can be undefined).
+
+
+shapeFunc :: Scalar -> Function3D
+shapeFunc res x y =
+ let
+ z = maxZeroIndex (ymandel x y) 0 1 20
+ in
+ if and [ maxZeroIndex (ymandel (x+xeps) (y+yeps)) 0 1 20 < 0.000001 |
+ val <- [res], xeps <- [-val,val], yeps<-[-val,val]]
+ then Nothing
+ else Just (z,colorFromValue ((ymandel x y z) * 64))
+
+
+
+
+
+-- given f min max nbtest,
+-- considering
+-- - f is an increasing function
+-- - f(min)=0
+-- - f(max)≠0
+-- then maxZeroIndex f min max nbtest returns x such that
+-- f(x - ε)=0 and f(x + ε)≠0
+-- where ε=(max-min)/2^(nbtest+1)
+maxZeroIndex :: (Fractional a,Num a,Num b,Eq b) =>
+ (a -> b) -> a -> a -> Int -> a
+maxZeroIndex _ minval maxval 0 = (minval+maxval)/2
+maxZeroIndex func minval maxval n =
+ if (func medpoint) /= 0
+ then maxZeroIndex func minval medpoint (n-1)
+ else maxZeroIndex func medpoint maxval (n-1)
+ where medpoint = (minval+maxval)/2
+
+ymandel :: Point -> Point -> Point -> Point
+ymandel x y z = fromIntegral (mandel x y z 64) / 64YGL.hs. It is commented a lot.
+
+YGL.hs, the 3D rendering frameworkMandel, the mandel functionExtComplex, the extended complexes
+Optimization
+YGL.hs, you’ll see I didn’t made everything perfect. For example, I didn’t finished the code of the lights. But I believe it is a good first step and it will be easy to go further. Unfortunately the program of the preceding session is extremely slow. We compute the Mandelbulb for each frame now.
+Constant Function -> Constant List of Triangles -> Display
+Main loop -> World -> Function -> List of Objects -> Atoms -> Display
+
+
+
+
+
+
+
+
+
+-- We initialize the world state
+-- then angle, position and zoom of the camera
+-- And the shape function
+initialWorld :: World
+initialWorld = World {
+ angle = makePoint3D (30,30,0)
+ , anglePerSec = 5.0
+ , position = makePoint3D (0,0,0)
+ , scale = 1.0
+ , box = Box3D { minPoint = makePoint3D (0-eps, 0-eps, 0-eps)
+ , maxPoint = makePoint3D (0+eps, 0+eps, 0+eps)
+ , resolution = 0.02 }
+ , told = 0
+ -- We declare cache directly this time
+ , cache = objectFunctionFromWorld initialWorld
+ }
+ where eps=2eps is a hint to make a better zoom by computing with the right bounds.YGL.getObject3DFromShapeFunction function directly. This way instead of providing XYFunc, we provide directly a list of Atoms.
+
+
+objectFunctionFromWorld :: World -> [YObject]
+objectFunctionFromWorld w = [Atoms atomList]
+ where atomListPositive =
+ getObject3DFromShapeFunction
+ (shapeFunc (resolution (box w))) (box w)
+ atomList = atomListPositive ++
+ map negativeTriangle atomListPositive
+ negativeTriangle (ColoredTriangle (p1,p2,p3,c)) =
+ ColoredTriangle (negz p1,negz p3,negz p2,c)
+ where negz (P (x,y,z)) = P (x,y,-z)
+
+
+YGL.hs source file.
+
+YGL.hs, the 3D rendering frameworkMandel, the mandel functionExtComplex, the extended complexesConclusion
+GLfloat, Color3 or any other OpenGL type. If I want to use another library in the future, I would be able to keep all the pure code and simply update the YGL module.YGL module can be seen as a “wrapper” around 3D display and user interaction. It is a clean separator between the imperative paradigm and functional paradigm.
+
+
+brew install libdevil. But even a minimal program who simply write some jpg didn’t worked. I tried both with Haskell and C.↩Complex Double, Complex Float, this current data type with Double and the actual version Float. For rendering a 1024x1024 Mandelbrot set it takes Complex Double about 6.8s, for Complex Float about 5.1s, for the actual version with Double and Float it takes about 1.6 sec. See these sources for testing yourself: https://gist.github.com/2945043. If you really want to things to go faster, use data Complex = C {-# UNPACK #-} !Float {-# UNPACK #-} !Float. It takes only one second instead of 1.6s.↩
+
+
+
+
+
+
+
+ Published on 2012-06-15
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/00_preamble.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/00_preamble.lhs
new file mode 100644
index 0000000..ae51c26
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/00_preamble.lhs
@@ -0,0 +1,124 @@
+begindiv(intro)
+
+en: I really believe all developers should learn Haskell.
+en: I don't think everyone needs to be super Haskell ninjas,
+en: but they should at least discover what Haskell has to offer.
+en: Learning Haskell opens your mind.
+fr: Je pense vraiment que
+fr: tous les développeurs devraient apprendre Haskell.
+fr: Peut-être pas devenir des ninjas d'Haskell,
+fr: mais au moins savoir ce que ce langage a de particulier.
+fr: Son apprentissage ouvre énormément l'esprit.
+
+en: Mainstream languages share the same foundations:
+fr: La plupart des langages partagent les mêmes fondements :
+
+en: - variables
+en: - loops
+en: - pointers[^0001]
+en: - data structures, objects and classes (for most)
+fr: - les variables
+fr: - les boucles
+fr: - les pointeurs[^0001]
+fr: - les structures de données, les objets et les classes
+
+en: [^0001]: Even if most recent languages try to hide them, they are present.
+fr: [^0001]: Même si tous les langages récents essayent de les cacher, ils restent présents.
+
+en: Haskell is very different.
+en: The language uses a lot of concepts I had never heard about before.
+en: Many of those concepts will help you become a better programmer.
+fr: Haskell est très différent.
+fr: Ce langage utilise des concepts dont je n'avais jamais entendu parler avant.
+fr: Beaucoup de ces concepts pourront vous aider à devenir un meilleur développeur.
+
+en: But learning Haskell can be hard.
+en: It was for me.
+en: In this article I try to provide what I lacked during my learning.
+fr: Plier son esprit à Haskell peut être difficile.
+fr: Ce le fut pour moi.
+fr: Dans cet article, j'essaye de fournir les informations qui m'ont manquées lors de mon apprentissage.
+
+en: This article will certainly be hard to follow.
+en: This is on purpose.
+en: There is no shortcut to learning Haskell.
+en: It is hard and challenging.
+en: But I believe this is a good thing.
+en: It is because it is hard that Haskell is interesting.
+fr: Cet article sera certainement difficile à suivre.
+fr: Mais c'est voulu.
+fr: Il n'y a pas de raccourci pour apprendre Haskell.
+fr: C'est difficile.
+fr: Mais je pense que c'est une bonne chose.
+fr: C'est entre autres parce qu'Haskell est difficile qu'il est intéressant.
+
+en: The conventional method to learning Haskell is to read two books.
+en: First ["Learn You a Haskell"](http://learnyouahaskell.com) and just after ["Real World Haskell"](http://www.realworldhaskell.org).
+en: I also believe this is the right way to go.
+en: But to learn what Haskell is all about, you'll have to read them in detail.
+fr: La manière conventionnelle d'apprendre Haskell est de lire deux livres.
+fr: D'abord ["Learn You a Haskell"](http://haskell.fr/lyah/)
+fr: et ensuite ["Real World Haskell"](http://www.realworldhaskell.org).
+fr: Je pense aussi que c'est la bonne manière de s'y prendre.
+fr: Mais apprendre même un tout petit peu d'Haskell est presque impossible sans se plonger réellement dans ces livres.
+
+en: In contrast, this article is a very brief and dense overview of all major aspects of Haskell.
+en: I also added some information I lacked while I learned Haskell.
+fr: Cet article fait un résumé très dense et rapide des aspects majeurs d'Haskell.
+fr: J'y ai aussi rajouté des informations qui m'ont manqué pendant l'apprentissage de ce langage.
+
+fr: Pour les francophones : je suis désolé.
+fr: Je n'ai pas eu le courage de tout retraduire en français.
+fr: Sachez cependant que si vous êtes plusieurs à insister, je ferai certainement l'effort de traduire l'article en entier.
+fr: Et si vous vous sentez d'avoir une bonne âme je ne suis pas contre un peu d'aide.
+fr: Les sources de cet article sont sur [github](http://github.com/yogsototh/learn_haskell.git).
+
+en: The article contains five parts:
+fr: Cet article contient cinq parties :
+
+en: - Introduction: a short example to show Haskell can be friendly.
+en: - Basic Haskell: Haskell syntax, and some essential notions.
+en: - Hard Difficulty Part:
+en: - Functional style; a progressive example, from imperative to functional style
+en: - Types; types and a standard binary tree example
+en: - Infinite Structure; manipulate an infinite binary tree!
+en: - Hell Difficulty Part:
+en: - Deal with IO; A very minimal example
+en: - IO trick explained; the hidden detail I lacked to understand IO
+en: - Monads; incredible how we can generalize
+en: - Appendix:
+en: - More on infinite tree; a more math oriented discussion about infinite trees
+
+fr: - Introduction : un exemple rapide pour montrer qu'Haskell peut être facile.
+fr: - Les bases d'Haskell : La syntaxe et des notions essentielles
+fr: - Partie difficile :
+fr: - Style fonctionnel : un exemple progressif, du style impératif au style fonctionnel ;
+fr: - Types : la syntaxe et un exemple d'arbre binaire ;
+fr: - Structure infinie : manipulons un arbre infini !
+fr: - Partie de difficulté infernale :
+fr: - Utiliser les IO : un exemple très minimal ;
+fr: - Le truc des IO révélé : les détails cachés d'IO qui m'ont manqués
+fr: - Les monades : incroyable à quel point on peut généraliser
+fr: - Appendice :
+fr: - Revenons sur les arbres infinis : une discussion plus mathématique sur la manipulation d'arbres infinis.
+
+en: > Note: Each time you see a separator with a filename ending in `.lhs`
+en: > you can click the filename to get this file.
+en: > If you save the file as `filename.lhs`, you can run it with
+en: >
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Haskell Tutorials, a tutorial
+
+
+
+
+
+
+
+
+
+
+
+
+
+Tutorial module containing nothing except documentation.Tutorial module in your cabal descriptiondoctest to check your documentation is up to date
+
+Hints
+Tutorials/Guides
+
+
+Tutorial (or Guide.GuideTopic)Tutorial module content:
+{-# OPTIONS_GHC -fno-warn-unused-imports #-}
+{-|
+ Use @my-package@ if you want to ...
+-}
+module Data.Duration.Tutorial (
+
+ -- * Introduction
+ -- $introduction
+
+ -- ** Subsection
+ -- $subsection
+
+ ) where
+
+import Data.Duration
+
+{- $introduction
+
+So here how you use it:
+
+ >>> humanReadableDuration 1002012.002
+ "11 days 14 hours 20 min 12s 2ms"
+
+The function is 'humanReadableDuration' and
+the you'll be able to click on it to go
+to its definition.
+
+You can add images: <<path-to-image.png title>>
+and links: <http://haskell-lang.org haskell>.
+
+-}
+
+{- $subsection
+
+This is a chuck of documentation
+not attached to any particular Haskell
+declaration with an untested code block:
+
+> answer = 42
+
+-}doctest.stack test or cabal test you’ll get errors if some example doesn’t work anymore.Examples (doctest)
+doctest is a great way to provide examples in your code documentation. These example will then be used as tests. Apparently it comes from Python community.doctest, this is very simple:
+-- | My function description
+--
+-- >>> myFunction 3 4
+-- 7
+myFunction :: Int -> Int -> Int
+myFunction = (+)test bloc in your .cabal file looking like this:
+test-suite doctest
+ type: exitcode-stdio-1.0
+ hs-source-dirs: test
+ main-is: DocTest.hs
+ build-depend: base >= 4.7 && < 5
+ , <YOUR_LIBRARY>
+ , Glob >= 0.7
+ , doctest >= 0.9.12test/DocTest.hs simply use
+module Main where
+
+import DocTest
+import System.FilePath.Glob (glob)
+
+main = glob "src/**/*.hs" >>= docTeststack test or cabal test will check the validity of your documentation.Bonuses
+Verifying documentation coverage
+
+
+stack install haddock or cabal install haddock
+> haddock src/**/*.hs
+Haddock coverage:
+ 100% ( 15 / 15) in 'Data.Duration'
+ 100% ( 3 / 3) in 'Data.Duration.Tutorial'Continuous Integration
+github simply create an account on travis..travis.yml file in your repo containing the content of the file here and remove the builds you don’t need. It will build your project using a lot of different GHC versions and environemnts.
+sudo: false
+
+addons:
+ apt:
+ packages:
+ - libgmp-dev
+
+# Caching so the next build will be fast too.
+cache:
+ directories:
+ - $HOME/.stack
+
+before_install:
+# Download and unpack the stack executable
+- mkdir -p ~/.local/bin
+- export PATH=$HOME/.local/bin:$PATH
+- travis_retry curl -L https://www.stackage.org/stack/linux-x86_64 | tar xz --wildcards --strip-components=1 -C ~/.local/bin '*/stack'
+
+script:
+ - stack setup && stack --no-terminal --skip-ghc-check testREADME.md file:Badges
+README.md file.shields.ioHackage
+
+Stackage
+stackage, please do it. It isn’t much work. Just edit a file to add your package. And you’ll could be able to add another badge:Creating a new project with
+stackstack I suggest you to use the tasty-travis template. It will include the boilerplate for:
+
+~/.stack/config.yaml like this:
+templates:
+ params:
+ author-name: Your Name
+ author-email: your@mail.com
+ copyright: 'Copyright: (c) 2016 Your Name'
+ github-username: yourusername
+ category: Development
+stack new my-project tasty-travisGenerated Documentation
+
+-- | My function description
+myFunction :: T1 -- ^ arg1 description
+ -> T2 -- ^ arg2 description
+myFunction arg1 arg2 = ...
+data MyData a b
+ = C1 a b -- ^ doc for constructor C1
+ | C2 a b -- ^ doc for constructor C2
+
+data MyData a b
+ = C { a :: TypeA -- ^ field a description
+ , b :: TypeB -- ^ field b description
+ }
+{-|
+Module : MyModule
+Description: Short description
+Copyright : (c)
+License : MIT
+
+Here is a longer description of this module.
+With some code symbol @MyType@.
+And also a block of code:
+
+@
+data MyData = C Int Int
+
+myFunction :: MyData -> Int
+@
+
+-}
+module MyModule (
+ -- * Classes
+ C(..),
+ -- * Types
+ -- ** A data type
+ T,
+ -- ** A record
+ R,
+ -- * Some functions
+ f, g
+ ) whereOther Random Ideas
+hayoo! and hoogle.hackage and stackage provide also a lot of informations.Create a doc with link to best practices
+lein new my-project a directory doc is created for you. It contains a file with a link to this blog post:Having a page by function/symbol with comments
+
+
+clojuredocs.org: try to search for reduce, update-in or index for example
+
+clojuredocs.org is an independant website from the official Clojure website.foldl for example. Also as there would be less information to display, it will make the design cleaner.
+
+/r/haskell. If only 1% of them would take 10 minutes adding a bit of documentation it will certainly change a lot of things in the percieved documentation quality.Design is important
+
+
+
+
+
+
+
+
+
+
+
+
+
+ Published on 2016-05-06
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+en: > runhaskell filename.lhs
+en: >
+en: >
+en: > Some might not work, but most will.
+en: > You should see a link just below.
+
+fr: > Note: Chaque fois que vous voyez un séparateur avec un nom de fichier se terminant par `lhs`, vous pouvez cliquer sur le nom de fichier et télécharger le fichier.
+fr: > Si vous sauvegardez le fichier sour le nom `filename.lhs`, vous pouvez l'exécuter avec :
+fr: >
+fr: > runhaskell filename.lhs
+fr: >
+fr: >
+fr: > Certains ne marcheront pas, mais la majorité vous donneront un résultat.
+fr: > Vous devriez voir un lien juste en dessous.
+
+enddiv
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/00_hello_world.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/00_hello_world.lhs
new file mode 100644
index 0000000..d1ddeed
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/00_hello_world.lhs
@@ -0,0 +1,76 @@
+Introduction
+
+en: Install
+fr: Installation
+
+blogimage("Haskell-logo.png", "Haskell logo")
+
+en: There are different way to install Haskell, I would recommend to use
+fr: Aujourd'huil je considère que la manière la plus aisée d'installer Haskell est d'utiliser
+[`stack`](https://haskellstack.org).
+
+en: There are other way to install Haskell on your system you could visit,
+en: you can learn more about it by visiting
+fr: Il y a d'autres maniètres d'installer Haskell sur votre system,
+fr: vous pouvez en savoir plus en visitant
+[haskell.org](https://haskell.org)
+en: or
+fr: ou
+[haskell-lang.org](https://haskell-lang.org)
+
+en: Tools:
+fr: Outils:
+
+en: - `ghc`: Compiler similar to gcc for `C`.
+en: - `ghci`: Interactive Haskell (REPL)
+en: - `runhaskell`: Execute a program without compiling it. Convenient but very slow compared to compiled programs.
+fr: - `ghc`: Compilateur similaire à gcc pour le langage `C`.
+fr: - `ghci`: Console Haskell interactive (Read-Eval-Print Loop)
+fr: - `runhaskell`: Exécuter un programme sans le compiler. Pratique mais très lent comparé aux programmes compilés.
+
+en: Don't be afraid
+fr: Ne soyez pas effrayés!
+
+blogimage("munch_TheScream.jpg","The Scream")
+
+en: Many books/articles about Haskell start by introducing some esoteric formula (quick sort, Fibonacci, etc...).
+en: I will do the exact opposite.
+en: At first I won't show you any Haskell super power.
+en: I will start with similarities between Haskell and other programming languages.
+en: Let's jump to the mandatory "Hello World".
+fr: Beaucoup de livres/articles sur Haskell commencent par présenter des formules ésotériques (Algorithmes de tri rapide, suite de Fibonacci, etc...).
+fr: Je ferai l'exact opposé
+fr: En premier lieu je ne vous montrerai pas les super-pouvoirs d'Haskell.
+fr: Je vais commencer par les similarités avec les autres langages de programmation.
+fr: Commençons par l'indispensable "Hello World!".
+
+> main = putStrLn "Hello World!"
+
+en: To run it, you can save this code in a `hello.hs` and:
+fr: Pour l'exécuter, vous pouvez enregistrer ce code dans un fichier `hello.hs` et:
+
+
+~ runhaskell ./hello.hs
+Hello World!
+
+
+en: or if you use `stack` first run `stack setup` and then:
+fr: ou si vous utilisez `stack` lancez d'abord `stack setup` et ensuite :
+
+
+~ stack runhaskell ./hello.hs
+Hello World!
+
+
+
+en: You could also download the literate Haskell source.
+en: You should see a link just above the introduction title.
+en: Download this file as `00_hello_world.lhs` and:
+fr: Vous pouvez également télécharger la source Haskell littérale.
+fr: Vous devriez voir un lien juste au dessus du titre de l'introduction.
+fr: Téléchargez ce fichier en tant que `00_hello_world.lhs` et:
+
+
+~ runhaskell 00_hello_world.lhs
+Hello World!
+
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/10_hello_you.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/10_hello_you.lhs
new file mode 100644
index 0000000..ec5ca13
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/10_hello_you.lhs
@@ -0,0 +1,52 @@
+en: Now, a program asking your name and replying "Hello" using the name you entered:
+fr: Maintenant, un programme qui demande votre nom et répond "Hello" suivit du nom que vous avez entré:
+
+> main = do
+> print "What is your name?"
+> name <- getLine
+> print ("Hello " ++ name ++ "!")
+
+en: First, let us compare this with similar programs in a few imperative languages:
+fr: Premièrement, comparons ce code avec ceux de quelques langages de programmation impératif:
+
+
+ # Python
+print "What is your name?"
+name = raw_input()
+print "Hello %s!" % name
+
+
+
+ # Ruby
+puts "What is your name?"
+name = gets.chomp
+puts "Hello #{name}!"
+
+
+
+// In C
+ #include
+
+en: The structure is the same, but there are some syntax differences.
+en: The main part of this tutorial will be dedicated to explaining why.
+fr: La structure est la même, mais il y a quelques différences de syntaxe.
+fr: La partie principale de ce tutoriel sera consacrée à expliquer cela.
+
+en: In Haskell there is a `main` function and every object has a type.
+en: The type of `main` is `IO ()`.
+en: This means `main` will cause side effects.
+fr: En Haskell il y a une fonction `main` tous les objets ont un type.
+fr: Le type de `main` est `IO ()`.
+fr: Cela veut dire que `main` causera des effets secondaires.
+
+en: Just remember that Haskell can look a lot like mainstream imperative languages.
+fr: Rappelez-vous just que Haskell peut ressembler énormément aux principaux langages impératifs.
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/20_very_basic.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/20_very_basic.lhs
new file mode 100644
index 0000000..297e21b
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/20_very_basic.lhs
@@ -0,0 +1,159 @@
+en: Very basic Haskell
+fr: Les bases de Haskell
+
+blogimage("picasso_owl.jpg","Picasso minimal owl")
+
+en: Before continuing you need to be warned about some essential properties of Haskell.
+fr: Avant de continuer, vous devez êtres avertis à propos de propriétés essentielles de Haskell.
+
+en: _Functional_
+fr: _Fonctionnel_
+
+en: Haskell is a functional language.
+en: If you have an imperative language background, you'll have to learn a lot of new things.
+en: Hopefully many of these new concepts will help you to program even in imperative languages.
+fr: Haskell est un langage fonctionnel
+fr: Si vous avez déjà travaillé avec un langage impératif, vous devrez apprendre beaucoup de nouvelles choses.
+fr: Heureusement beaucoup de ces nouveaux concepts vous aidera à programmer même dans un langage impératif.
+
+en: _Smart Static Typing_
+fr: _Typage Statique Intelligent_
+
+en: Instead of being in your way like in `C`, `C++` or `Java`, the type system is here to help you.
+fr: Au lieu de bloquer votre chemin comme en `C`, `C++` ou `Java`, le système de typage est ici pour vous aider.
+
+en: _Purity_
+fr: _Pureté_
+
+en: Generally your functions won't modify anything in the outside world.
+en: This means they can't modify the value of a variable, can't get user input, can't write on the screen, can't launch a missile.
+en: On the other hand, parallelism will be very easy to achieve.
+en: Haskell makes it clear where effects occur and where your code is pure.
+en: Also, it will be far easier to reason about your program.
+en: Most bugs will be prevented in the pure parts of your program.
+fr: Généralement vos fonctions ne modifieront rien du le monde extérieur.
+fr: Cela veut dire qu'elles ne peuvent pas modifier la valeur d'une variable,
+fr: lire du texte entré par un utilisateur,
+fr: écrire sur l'écran, lancer un missile.
+fr: D'un autre coté, avoir un code parallèle devient très facile.
+fr: Haskell rend très clair où les effets apparaissent et où le code est pur.
+fr: De plus, il devient beaucoup plus aisé de raisonner sur son programme.
+fr: La majorité des bugs seront évités dans les parties pures de votre programme.
+
+en: Furthermore, pure functions follow a fundamental law in Haskell:
+fr: En outre, les fonctions pures suivent une loi fondamentale en Haskell:
+
+en: > Applying a function with the same parameters always returns the same value.
+fr: > Appliquer une fonction avec les mêmes paramètres retourne toujours la même valeur.
+
+en: _Laziness_
+fr: _Paresse_
+
+en: Laziness by default is a very uncommon language design.
+en: By default, Haskell evaluates something only when it is needed.
+en: In consequence, it provides a very elegant way to manipulate infinite structures, for example.
+fr: La paresse par défaut est un choix de conception de langage très rare.
+fr: Par défaut, Haskell évalue quelque chose seulement lorsque cela est nécessaire.
+fr: En conséquence, cela fournit un moyen très élégant de manipuler des structures infinies, par exemple.
+
+en: A last warning about how you should read Haskell code.
+en: For me, it is like reading scientific papers.
+en: Some parts are very clear, but when you see a formula, just focus and read slower.
+en: Also, while learning Haskell, it _really_ doesn't matter much if you don't understand syntax details.
+en: If you meet a `>>=`, `<$>`, `<-` or any other weird symbol, just ignore them and follows the flow of the code.
+fr: Un dernier avertissement sur comment vous devriez lire le code Haskell.
+fr: Pour moi, c'est comme lire des papiers scientifiques.
+fr: Quelques parties sont très claires, mais quand vous voyez une formule, concentrez-vous dessus et lisez plus lentement.
+fr: De plus, lorsque vous apprenez Haskell, cela n'importe _vraiment_ pas si vous ne comprenez pas les détails syntaxiques.
+fr: Si vous voyez un `>>=`, `<$>`, `<-` ou n'importe quel symbole bizarre, ignorez-les et suivez le déroulement du code.
+
+en: Function declaration
+fr: Déclaration de fonctions
+
+en: You might be used to declaring functions like this:
+fr: Vous avez déjà dû déclarer des fonctions comme cela:
+
+en: In `C`:
+fr: En `C`:
+
+
+int f(int x, int y) {
+ return x*x + y*y;
+}
+
+
+en: In JavaScript:
+fr: En JavaScript:
+
+
+function f(x,y) {
+ return x*x + y*y;
+}
+
+
+en: in Python:
+fr: En Python:
+
+
+def f(x,y):
+ return x*x + y*y
+
+
+en: in Ruby:
+fr: En Ruby:
+
+
+def f(x,y)
+ x*x + y*y
+end
+
+
+en: In Scheme:
+fr: En Scheme:
+
+
+(define (f x y)
+ (+ (* x x) (* y y)))
+
+
+en: Finally, the Haskell way is:
+fr: Finalement, la manière de faire de Haskell est:
+
+
+f x y = x*x + y*y
+
+
+en: Very clean. No parenthesis, no `def`.
+fr: Très propre. Aucune parenthèse, aucun `def`.
+
+en: Don't forget, Haskell uses functions and types a lot.
+en: It is thus very easy to define them.
+en: The syntax was particularly well thought out for these objects.
+fr: N'oubliez pas, Haskell utilise beaucoup les fonctions et les types.
+fr: C'est très facile de les définir.
+fr: La syntaxe a été particulièrement réfléchie pour ces objets.
+
+en: A Type Example
+fr: Un exemple de type
+
+en: Although it is not mandatory, type information for functions is usually made
+en: explicit. It's not mandatory because the compiler is smart enough to discover
+en: it for you. It's a good idea because it indicates intent and understanding.
+fr: Même si ce n'est pas obligatoire, les informations de type pour les fonctions sont habituellement déclarées
+fr: explicitement. Ce n'est pas indispensable car le compilateur est suffisamment intelligent pour le déduire
+fr: à votre place. Cependant, c'est une bonne idée car cela montre bien l'intention du développeur et facilite la compréhension.
+
+en: Let's play a little.
+en: We declare the type using `::`
+fr: Jouons un peu.
+fr: On déclare le type en utilisant `::`
+
+> f :: Int -> Int -> Int
+> f x y = x*x + y*y
+>
+> main = print (f 2 3)
+
+~~~
+~ runhaskell 20_very_basic.lhs
+13
+~~~
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/21_very_basic.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/21_very_basic.lhs
new file mode 100644
index 0000000..8d49e0c
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/21_very_basic.lhs
@@ -0,0 +1,23 @@
+en: Now try
+fr: Maintenant essayez
+
+> f :: Int -> Int -> Int
+> f x y = x*x + y*y
+>
+> main = print (f 2.3 4.2)
+
+en: You should get this error:
+fr: Vous devriez avoir cette erreur:
+
+~~~
+21_very_basic.lhs:6:23:
+ No instance for (Fractional Int)
+ arising from the literal `4.2'
+ Possible fix: add an instance declaration for (Fractional Int)
+ In the second argument of `f', namely `4.2'
+ In the first argument of `print', namely `(f 2.3 4.2)'
+ In the expression: print (f 2.3 4.2)
+~~~
+
+en: The problem: `4.2` isn't an Int.
+fr: Le problème est que `4.2` n'est pas de type `Int` (_NDT: Il n'est pas un entier_)
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/22_very_basic.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/22_very_basic.lhs
new file mode 100644
index 0000000..1ef0e2a
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/22_very_basic.lhs
@@ -0,0 +1,170 @@
+en: The solution: don't declare a type for `f` for the moment and let Haskell infer the most general type for us:
+fr: La soulution: ne déclarez pas de type pour `f` pour le moment et laissez Haskell inférer le type le plus général pour nous:
+
+> f x y = x*x + y*y
+>
+> main = print (f 2.3 4.2)
+
+en: It works!
+en: Luckily, we don't have to declare a new function for every single type.
+en: For example, in `C`, you'll have to declare a function for `int`, for `float`, for `long`, for `double`, etc...
+fr: Maintenant, ça marche!
+fr: Heureursement, nous n'avons pas à déclarer un nouvelle fonction pour chaque type différent.
+fr: Par exemple, en `C`, vous auriez dû déclarer un fonction pour `int`, pour `float`, pour `long`, pour `double`, etc...
+
+en: But, what type should we declare?
+en: To discover the type Haskell has found for us, just launch ghci:
+fr: Mais quel type devons nous déclarer?
+fr: Pour découvrir le type que Haskell a trouvé pour nous, lançons ghci:
+
+
+% ghci
+
+en: Uh? What is this strange type?
+fr: Hein? Quel ce type étrange?
+
+~~~
+Num a => a -> a -> a
+~~~
+
+en: First, let's focus on the right part `a -> a -> a`.
+en: To understand it, just look at a list of progressive examples:
+fr: Premièrement, concentrons-nous sur la partie de droite: `a -> a -> a`.
+fr: Pour le comprendre, regardez cette liste d'exemples progressifs:
+
+en: --------------------------------------------------------------------------------------------------
+en: The written type Its meaning
+en: -------------------------- -----------------------------------------------------------------------
+en: `Int` the type `Int`
+en:
+en: `Int -> Int` the type function from `Int` to `Int`
+en:
+en: `Float -> Int` the type function from `Float` to `Int`
+en:
+en: `a -> Int` the type function from any type to `Int`
+en:
+en: `a -> a` the type function from any type `a` to the same type `a`
+en:
+en: `a -> a -> a` the type function of two arguments of any type `a` to the same type `a`
+en: --------------------------------------------------------------------------------------------------
+fr: --------------------------------------------------------------------------------------------------------------------------------------
+fr: Le type écrit Son sens
+fr: -------------------------- -----------------------------------------------------------------------------------------------------------
+fr: `Int` Le type `Int`
+fr:
+fr: `Int -> Int` Le type de la fonction qui prend un `Int` et retourne un `Int`
+fr:
+fr: `Float -> Int` Le type de la fonction qui prend un `Float` et retourne un `Int`
+fr:
+fr: `a -> Int` Le type de la fonction qui prend n'importe quel type de variable et retourne un `Int`
+fr:
+fr: `a -> a` Le type de la fonction qui prend n'importe quel type `a` et retourne une variable du même type `a`
+fr:
+fr: `a -> a -> a` Le type de la fonction qui prend de arguments de n'importe quel type`a` et retourne une variable de type `a`
+fr: --------------------------------------------------------------------------------------------------------------------------------------
+
+en: In the type `a -> a -> a`, the letter `a` is a _type variable_.
+en: It means `f` is a function with two arguments and both arguments and the result have the same type.
+en: The type variable `a` could take many different type values.
+en: For example `Int`, `Integer`, `Float`...
+fr: Dans le type `a -> a -> a`, la lettre `a` est une _variable de type_.
+fr: Cela signifie que `f` est une fonction avec deux arguments et que les deux arguments et le résultat ont le même type.
+fr: La variable de type `a` peut prendre de nombreuses valeurs différentes
+fr: Par exemple `Int`, `Integer`, `Float`...
+
+en: So instead of having a forced type like in `C` and having to declare a function
+en: for `int`, `long`, `float`, `double`, etc., we declare only one function like
+en: in a dynamically typed language.
+fr: Donc à la place d'avoir un type forcé comme en `C` et de devoir déclarer une fonction
+fr: pour `int`, `long`, `float`, `double`, etc., nous déclarons une seule fonction comme
+fr: dans un langage typé de façon dynamique.
+
+en: This is sometimes called parametric polymorphism. It's also called having your
+en: cake and eating it too.
+fr: C'est parfois appelé le polymorphisme paramétrique. C'est aussi appelé avoir un
+fr: gâteau et le manger.
+
+en: Generally `a` can be any type, for example a `String` or an `Int`, but also
+en: more complex types, like `Trees`, other functions, etc. But here our type is
+en: prefixed with `Num a => `.
+fr: Généralement `a` peut être de n'importe quel type, par exemple un `String` ou un `Int`, mais aussi
+fr: des types plus complexes comme `Trees`, d'autres fonctions, etc. Mais ici notre type est
+fr: préfixé par `Num a => `.
+
+en: `Num` is a _type class_.
+en: A type class can be understood as a set of types.
+en: `Num` contains only types which behave like numbers.
+en: More precisely, `Num` is class containing types which implement a specific list of functions, and in particular `(+)` and `(*)`.
+fr: `Num` est une _classe de type_.
+fr: Une classe de type peut être comprise comme un ensemble de types
+fr: `Num` contient seulement les types qui se comportent comme des nombres.
+fr: Plus précisement, `Num` est une classe qui contient des types qui implémentent une liste spécifique de fonctions,
+fr: en particulier `(+)` et `(*)`.
+
+en: Type classes are a very powerful language construct.
+en: We can do some incredibly powerful stuff with this.
+en: More on this later.
+fr: Les classes de types sont une structure de langage très puissante.
+fr: Nous pouvons faire des trucs incroyablement puissants avec.
+fr: Nous verrons cela plus tard.
+
+en: Finally, `Num a => a -> a -> a` means:
+fr: Finalement, `Num a => a -> a -> a` signifie:
+
+en: Let `a` be a type belonging to the `Num` type class.
+en: This is a function from type `a` to (`a -> a`).
+fr: soit `a` un type qui appartient à la classe `Num`.
+fr: C'est une fonction qui prend une variable de type `a` et retourne une fonction de type `(a -> a)`
+
+en: Yes, strange.
+en: In fact, in Haskell no function really has two arguments.
+en: Instead all functions have only one argument.
+en: But we will note that taking two arguments is equivalent to taking one argument and returning a function taking the second argument as a parameter.
+fr: Oui, c'est étrange.
+fr: En fait, en Haskell aucune fonction ne prend réellement deux arguments.
+fr: Au lieu de cela toutes les fonctions n'ont qu'un argument unique.
+fr: Mais nous retiendrons que prendre deux arguments est équivalent à n'en prendre qu'un et à retourner une fonction qui prend le second argument en paramètre.
+
+en: More precisely `f 3 4` is equivalent to `(f 3) 4`.
+en: Note `f 3` is a function:
+fr: Plus précisement `f 3 4` est équivalent à `(f 3) 4 `.
+fr: Remarque: `f 3` est une fonction:
+
+~~~
+f :: Num a => a -> a -> a
+
+g :: Num a => a -> a
+g = f 3
+
+g y ⇔ 3*3 + y*y
+~~~
+
+en: Another notation exists for functions.
+en: The lambda notation allows us to create functions without assigning them a name.
+en: We call them anonymous functions.
+en: We could also have written:
+fr: Une autre notation existe pour les fonctions.
+fr: La notation lambda nous autorise à créer des fonctions sans leur assigner un nom.
+fr: On les appelle des fonctions anonymes.
+fr: nous aurions donc pu écrire:
+
+~~~
+g = \y -> 3*3 + y*y
+~~~
+
+en: The `\` is used because it looks like `λ` and is ASCII.
+fr: Le `\` esst utilisé car il ressemble à un `λ` et est un caractère ASCII.
+
+en: If you are not used to functional programming your brain should be starting to heat up.
+en: It is time to make a real application.
+fr: Si vous n'êtes pas habitué à la programmation fonctionnelle, votre cerveau devrait commencer à chauffer
+fr: Il est temps de faire une vraie application.
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/23_very_basic.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/23_very_basic.lhs
new file mode 100644
index 0000000..f6881e3
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/23_very_basic.lhs
@@ -0,0 +1,12 @@
+en: But just before that, we should verify the type system works as expected:
+fr: Mais juste avant cela, nous devrions vérifier que le système de type marche comme nous le supposons:
+
+> f :: Num a => a -> a -> a
+> f x y = x*x + y*y
+>
+> main = print (f 3 2.4)
+
+en: It works, because, `3` is a valid representation both for Fractional numbers like Float and for Integer.
+en: As `2.4` is a Fractional number, `3` is then interpreted as being also a Fractional number.
+fr: Cela fonctionne, car `3` est une représentation valide autant pour les nombres fractionnaires comme Float que pour les entiers.
+fr: Comme `2.4` est un nombre fractionnaire, `3` est interprété comme une autre nombre fractionnaire
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/24_very_basic.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/24_very_basic.lhs
new file mode 100644
index 0000000..8512c6b
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/10_Introduction/24_very_basic.lhs
@@ -0,0 +1,24 @@
+en: If we force our function to work with different types, it will fail:
+fr: Si nous forçons notre fonction à travailler avec des types différents, le test échouera:
+
+> f :: Num a => a -> a -> a
+> f x y = x*x + y*y
+>
+> x :: Int
+> x = 3
+> y :: Float
+> y = 2.4
+> -- won't work because type x ≠ type y
+> main = print (f x y)
+
+en: The compiler complains.
+en: The two parameters must have the same type.
+fr: Le compilateur se plaint.
+fr: Les deux paramètres doivent avoir le même type.
+
+en: If you believe that this is a bad idea, and that the compiler should make the transformation
+en: from one type to another for you, you should really watch this great (and funny) video:
+en: [WAT](https://www.destroyallsoftware.com/talks/wat)
+fr: Si vous pensez que c'est une mauvaise idée et que le compilateur devrait faire la transformation
+fr: depuis un type à un autre pour vous, vous devriez vraiment regarder cette vidéo géniale (et amusante):
+fr: [WAT](https://www.destroyallsoftware.com/talks/wat) (_NDT: En Anglais_)
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/20_Essential_Haskell/00_notations.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/20_Essential_Haskell/00_notations.lhs
new file mode 100644
index 0000000..7744b8d
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/20_Essential_Haskell/00_notations.lhs
@@ -0,0 +1,171 @@
+en:
+GHCi, version 7.0.4: http://www.haskell.org/ghc/ :? for help
+Loading package ghc-prim ... linking ... done.
+Loading package integer-gmp ... linking ... done.
+Loading package base ... linking ... done.
+Loading package ffi-1.0 ... linking ... done.
+Prelude> let f x y = x*x + y*y
+Prelude> :type f
+f :: Num a => a -> a -> a
+Essential Haskell
+fr: Notions essentielles
+
+blogimage("kandinsky_gugg.jpg","Kandinsky Gugg")
+
+en: I suggest that you skim this part.
+en: Think of it as a reference.
+en: Haskell has a lot of features.
+en: A lot of information is missing here.
+en: Come back here if the notation feels strange.
+fr: Je vous suggère de seulement survoler cette partie
+fr: Pensez-y seulement comme à une référence.
+fr: Haskell a beaucoup de caractèristiques
+fr: Il manque beaucoup d'informations ici.
+fr: Revenz ici si la notation vous semble étrange.
+
+en: I use the `⇔` symbol to state that two expression are equivalent.
+en: It is a meta notation, `⇔` does not exists in Haskell.
+en: I will also use `⇒` to show what the return value of an expression is.
+fr: J'utilise le symbole `⇔` pour signifier que deux expressions sont équivalentes.
+fr: C'est une notation extérieure, `⇔` n'existe pas en Haskell.
+fr: Je vais aussi utiliser le symoble `⇒` quelle est la valeur que retourne une fonction.
+
+Notations
+
+en: Arithmetic
+fr: Arithmétique
+
+~~~
+3 + 2 * 6 / 3 ⇔ 3 + ((2*6)/3)
+~~~
+
+en: Logic
+fr: Logique
+
+~~~
+True || False ⇒ True
+True && False ⇒ False
+True == False ⇒ False
+en: True /= False ⇒ True (/=) is the operator for different
+fr: True /= False ⇒ True (/=) est l'opérateur pour "différent de"
+~~~
+
+en: Powers
+fr: Puissances
+
+~~~
+en: x^n for n an integral (understand Int or Integer)
+en: x**y for y any kind of number (Float for example)
+fr: x^n pour n un entier (comprenez Int ou Integer)
+fr: x**y pour y tout type de nombre (Float par exemple)
+~~~
+
+en: `Integer` has no limit except the capacity of your machine:
+fr: `Integer` n'a aucune limite à part la capacité de votre machine:
+
+~~~
+4^103
+102844034832575377634685573909834406561420991602098741459288064
+~~~
+
+Yeah!
+en: And also rational numbers FTW!
+en: But you need to import the module `Data.Ratio`:
+fr: Et aussi les nombres rationnels!
+fr: Mais vous avez besoin d'importer le module `Data.Ratio`
+
+~~~
+$ ghci
+....
+Prelude> :m Data.Ratio
+Data.Ratio> (11 % 15) * (5 % 3)
+11 % 9
+~~~
+
+en: Lists
+fr: Listes
+
+~~~
+en: [] ⇔ empty list
+en: [1,2,3] ⇔ List of integral
+en: ["foo","bar","baz"] ⇔ List of String
+en: 1:[2,3] ⇔ [1,2,3], (:) prepend one element
+en: 1:2:[] ⇔ [1,2]
+en: [1,2] ++ [3,4] ⇔ [1,2,3,4], (++) concatenate
+en: [1,2,3] ++ ["foo"] ⇔ ERROR String ≠ Integral
+en: [1..4] ⇔ [1,2,3,4]
+en: [1,3..10] ⇔ [1,3,5,7,9]
+en: [2,3,5,7,11..100] ⇔ ERROR! I am not so smart!
+en: [10,9..1] ⇔ [10,9,8,7,6,5,4,3,2,1]
+fr: [] ⇔ liste vide
+fr: [1,2,3] ⇔ Liste d'entiers
+fr: ["foo","bar","baz"] ⇔ Liste de chaînes de caractères
+fr: 1:[2,3] ⇔ [1,2,3], (:) ajoute un élément au début
+fr: 1:2:[] ⇔ [1,2]
+fr: [1,2] ++ [3,4] ⇔ [1,2,3,4], (++) concaténation de deux listes
+fr: [1,2,3] ++ ["foo"] ⇔ ERREUR String ≠ Integral
+fr: [1..4] ⇔ [1,2,3,4]
+fr: [1,3..10] ⇔ [1,3,5,7,9]
+fr: [2,3,5,7,11..100] ⇔ ERREUR! Je ne suis pas si intelligent!
+fr: [10,9..1] ⇔ [10,9,8,7,6,5,4,3,2,1]
+~~~
+
+en: Strings
+fr: Chaînes de caractères
+
+en: In Haskell strings are list of `Char`.
+fr: En Haskell les chaînes de caractères sont des listes de `Char`.
+
+~~~
+'a' :: Char
+"a" :: [Char]
+"" ⇔ []
+"ab" ⇔ ['a','b'] ⇔ 'a':"b" ⇔ 'a':['b'] ⇔ 'a':'b':[]
+"abc" ⇔ "ab"++"c"
+~~~
+
+en: > _Remark_:
+en: > In real code you shouldn't use list of char to represent text.
+en: > You should mostly use `Data.Text` instead.
+en: > If you want to represent a stream of ASCII char, you should use `Data.ByteString`.
+fr: > _Remarque_:
+fr: > Dans un vrai code vous n'utiliserez pas des listes de char pour représenter du texte.
+fr: > Vous utiliserez plus souvent `Data.Text` à la place.
+fr: > Si vous voulez représenter un chapelet de caractères ASCII, vous utiliserez `Data.ByteString`.
+
+Tuples
+
+en: The type of couple is `(a,b)`.
+en: Elements in a tuple can have different types.
+fr: Le type d'un couple est `(a,b)`.
+fr: Les éléments d'un tuple peuvent avoir des types différents.
+
+~~~
+en: -- All these tuples are valid
+fr: -- tous ces tuples sont valides
+(2,"foo")
+(3,'a',[2,3])
+((2,"a"),"c",3)
+
+fst (x,y) ⇒ x
+snd (x,y) ⇒ y
+
+fst (x,y,z) ⇒ ERROR: fst :: (a,b) -> a
+snd (x,y,z) ⇒ ERROR: snd :: (a,b) -> b
+~~~
+
+en: Deal with parentheses
+fr: Traiter avec les parenthèses
+
+en: To remove some parentheses you can use two functions: `($)` and `(.)`.
+fr: Pour enlever des parenthèses vous pouvez utiliser deux fonctions: `($)` et `(.)`.
+
+~~~
+en: -- By default:
+fr: -- Par défaut:
+f g h x ⇔ (((f g) h) x)
+
+en: -- the $ replace parenthesis from the $
+en: -- to the end of the expression
+fr: -- le $ remplace les parenthèses depuis le $
+fr: -- jusqu'à la fin de l'expression.
+f g $ h x ⇔ f g (h x) ⇔ (f g) (h x)
+f $ g h x ⇔ f (g h x) ⇔ f ((g h) x)
+f $ g $ h x ⇔ f (g (h x))
+
+en: -- (.) the composition function
+fr: -- (.) permet de faire des compositions de fonctions
+(f . g) x ⇔ f (g x)
+(f . g . h) x ⇔ f (g (h x))
+~~~
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/20_Essential_Haskell/10a_Functions.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/20_Essential_Haskell/10a_Functions.lhs
new file mode 100644
index 0000000..5d543b2
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/01_basic/20_Essential_Haskell/10a_Functions.lhs
@@ -0,0 +1,99 @@
+en: Useful notations for functions
+fr: Notations utiles pour les fonctions
+
+en: Just a reminder:
+fr: Juste un mémo:
+
+~~~
+en: x :: Int ⇔ x is of type Int
+en: x :: a ⇔ x can be of any type
+en: x :: Num a => a ⇔ x can be any type a
+en: such that a belongs to Num type class
+en: f :: a -> b ⇔ f is a function from a to b
+en: f :: a -> b -> c ⇔ f is a function from a to (b→c)
+en: f :: (a -> b) -> c ⇔ f is a function from (a→b) to c
+fr: x :: Int ⇔ x est de type Int
+fr: x :: a ⇔ x peut être de n'importe quel type
+fr: x :: Num a => a ⇔ x peut être de n'importe quel type a
+fr: tant qu' a appartient à la classe de type Num
+fr: f :: a -> b ⇔ f est une fonction qui prend un a et retourne un b
+fr: f :: a -> b -> c ⇔ f est une fonction qui prend un a et retourne un (b→c)
+fr: f :: (a -> b) -> c ⇔ f est une fonction qui prend un (a→b) et retourne un c
+~~~
+
+en: Remember that defining the type of a function before its declaration isn't mandatory.
+en: Haskell infers the most general type for you.
+en: But it is considered a good practice to do so.
+fr: Rappelez-vous que définir le type d'une fonction avant sa déclaration n'est pas obligatoire.
+fr: Haskell infère le type le plus général pour vous.
+fr: Mais c'est considéré comme une bonne pratique.
+
+en: _Infix notation_
+fr: _Notation Infixée_
+
+> square :: Num a => a -> a
+> square x = x^2
+
+en: Note `^` uses infix notation.
+en: For each infix operator there its associated prefix notation.
+en: You just have to put it inside parenthesis.
+fr: Remarquez que `^` utilise une notation infixée.
+fr: Pour chaque opérateur infixe il y a une notation préfixée associée.
+fr: Vous devz juste l'écrire entre parenthèses.
+
+> square' x = (^) x 2
+>
+> square'' x = (^2) x
+
+en: We can remove `x` in the left and right side!
+en: It's called η-reduction.
+fr: Nous pouvons enlever le `x` dans les parties de gauche et de droite!
+fr: On appelle cela la η-réduction
+
+> square''' = (^2)
+
+en: Note we can declare functions with `'` in their name.
+en: Here:
+fr: Rmarquez qu nous pouvons déclarer des fonctions avec `'` dans leur nom.
+fr: Exemples:
+
+ > `square` ⇔ `square'` ⇔ `square''` ⇔ `square'''`
+
+_Tests_
+
+en: An implementation of the absolute function.
+fr: Une implémentation de la fonction absolue.
+
+> absolute :: (Ord a, Num a) => a -> a
+> absolute x = if x >= 0 then x else -x
+
+en: Note: the `if .. then .. else` Haskell notation is more like the
+en: `¤?¤:¤` C operator. You cannot forget the `else`.
+fr: Remarque: la notation de Haskell pour le `if .. then .. else` ressemble plus
+fr: à l'opérateur `¤?¤:¤` en C. Le `else` est obligatoire.
+
+en: Another equivalent version:
+fr: Une version équivalente:
+
+> absolute' x
+> | x >= 0 = x
+> | otherwise = -x
+
+en: > Notation warning: indentation is _important_ in Haskell.
+en: > Like in Python, bad indentation can break your code!
+fr: > Avertissement: l'indentation est _importante_ en Haskell.
+fr: > Comme en Python, une mauvaise indentation peut détruire votre code!
+
+
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/10_Functions.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/10_Functions.lhs
new file mode 100644
index 0000000..02df0e4
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/10_Functions.lhs
@@ -0,0 +1,133 @@
+en: Hard Part
+fr: La Partie Difficile
+
+en: The hard part can now begin.
+fr: La partie difficile peut maintenant commencer.
+
+en: Functional style
+fr: Le style fonctionnel
+
+blogimage("hr_giger_biomechanicallandscape_500.jpg","Biomechanical Landscape by H.R. Giger")
+
+en: In this section, I will give a short example of the impressive refactoring ability provided by Haskell.
+en: We will select a problem and solve it in a standard imperative way.
+en: Then I will make the code evolve.
+en: The end result will be both more elegant and easier to adapt.
+fr: Dans cette section, je vais vous donner un court exemple de l'impressionante capacité de remaniement de Haskell.
+fr: Nous allons sélectionner un problème et le résoudre à la manière d'un langage impératif standard.
+fr: Ensuite, je ferais évoluer le code.
+fr: Le résultat final sera plus élégant et plus facile à adapter.
+
+en: Let's solve the following problem:
+fr: résolvons les problèmes suivants:
+
+en: > Given a list of integers, return the sum of the even numbers in the list.
+fr: > Soit une liste d'entiers, retourner la somme des nombres pairs de cette liste.
+ >
+en: > example:
+fr: > exemple:
+ > `[1,2,3,4,5] ⇒ 2 + 4 ⇒ 6`
+
+en: To show differences between functional and imperative approaches,
+en: I'll start by providing an imperative solution (in JavaScript):
+fr: Pour montrer les différences entre les approches fonctionnelle et impérative,
+fr: je vais commencer par donner la solution impérative (en JavaScript):
+
+
+function evenSum(list) {
+ var result = 0;
+ for (var i=0; i< list.length ; i++) {
+ if (list[i] % 2 ==0) {
+ result += list[i];
+ }
+ }
+ return result;
+}
+
+
+en: In Haskell, by contrast, we don't have variables or a for loop.
+en: One solution to achieve the same result without loops is to use recursion.
+fr: En Haskell, en revanche, nous n'avons pas de variables ou un boucle `for`.
+fr: Une des solutions pour parvenir au même résultat sans boucles est d'utiliser la récursion.
+
+en: > _Remark_:
+en: > Recursion is generally perceived as slow in imperative languages.
+en: > But this is generally not the case in functional programming.
+en: > Most of the time Haskell will handle recursive functions efficiently.
+fr: > _Remarque_:
+fr: > La récursion est souvent perçue comme lente dans les langages impératifs.
+fr: > Mais ce n'est généralement pas le cas en programmation fonctionnelle.
+fr: > La plupart du temps Haskell gérera les fonctions récursives efficacement.
+
+en: Here is a `C` version of the recursive function.
+en: Note that for simplicity I assume the int list ends with the first `0` value.
+fr: Voici la version `C` de la fonction récursive.
+fr: Remarquez que je suppose que la liste d'int fini avec la première valeur `0`.
+
+
+
+int evenSum(int *list) {
+ return accumSum(0,list);
+}
+
+int accumSum(int n, int *list) {
+ int x;
+ int *xs;
+ if (*list == 0) { // if the list is empty
+ return n;
+ } else {
+ x = list[0]; // let x be the first element of the list
+ xs = list+1; // let xs be the list without x
+ if ( 0 == (x%2) ) { // if x is even
+ return accumSum(n+x, xs);
+ } else {
+ return accumSum(n, xs);
+ }
+ }
+}
+
+
+en: Keep this code in mind. We will translate it into Haskell.
+en: First, however, I need to introduce three simple but useful functions we will use:
+fr: Gardez ce code à l'esprit. Nous allons le traduire en Haskell.
+fr: Premièrement,
+
+
+even :: Integral a => a -> Bool
+head :: [a] -> a
+tail :: [a] -> [a]
+
+
+en: `even` verifies if a number is even.
+fr: `even` vérifie si un nombre est pair.
+
+
+even :: Integral a => a -> Bool
+even 3 ⇒ False
+even 2 ⇒ True
+
+
+en: `head` returns the first element of a list:
+fr: `head` retourne le premier élément d'une liste:
+
+
+head :: [a] -> a
+head [1,2,3] ⇒ 1
+head [] ⇒ ERROR
+
+
+en: `tail` returns all elements of a list, except the first:
+fr: `tail` retourne tous les éléments d'une liste, sauf le premier:
+
+
+tail :: [a] -> [a]
+tail [1,2,3] ⇒ [2,3]
+tail [3] ⇒ []
+en: tail [] ⇒ ERROR
+fr: tail [] ⇒ ERREUR
+
+
+en: Note that for any non empty list `l`,
+en: `l ⇔ (head l):(tail l)`
+fr: Remarquez que pour toute liste non-vide `l`,
+fr: `l ⇔ (head l):(tail l)`
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/11_Functions.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/11_Functions.lhs
new file mode 100644
index 0000000..cc34f13
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/11_Functions.lhs
@@ -0,0 +1,80 @@
+en: The first Haskell solution.
+en: The function `evenSum` returns the sum of all even numbers in a list:
+fr: La première solution en Haskell.
+fr: La fonction `evenSum` retourne la somme de tous les nombres pairs d'une liste:
+
+> -- Version 1
+> evenSum :: [Integer] -> Integer
+>
+> evenSum l = accumSum 0 l
+>
+> accumSum n l = if l == []
+> then n
+> else let x = head l
+> xs = tail l
+> in if even x
+> then accumSum (n+x) xs
+> else accumSum n xs
+
+en: To test a function you can use `ghci`:
+fr: Pour tester une fonction nous pouvons utiliser `ghci`:
+
+
+% ghci
+GHCi, version 7.0.3: http://www.haskell.org/ghc/ :? for help
+Loading package ghc-prim ... linking ... done.
+Loading package integer-gmp ... linking ... done.
+Loading package base ... linking ... done.
+Prelude> :load 11_Functions.lhs
+[1 of 1] Compiling Main ( 11_Functions.lhs, interpreted )
+Ok, modules loaded: Main.
+*Main> evenSum [1..5]
+6
+
+
+en: Here is an example of execution[^2]:
+fr: Voici un exemple d'exécution[^2]:
+
+en: [^2]: I know I'm cheating. But I will talk about non-strictness later.
+fr: [^2]: Je sais que je triche. Mais je parlerais de la non-rigueur plus tard.
+
+
+*Main> evenSum [1..5]
+accumSum 0 [1,2,3,4,5]
+en: 1 is odd
+fr: 1 est impair
+accumSum 0 [2,3,4,5]
+en: 2 is even
+fr: 2 est pair
+accumSum (0+2) [3,4,5]
+en: 3 is odd
+fr: 3 est impair
+accumSum (0+2) [4,5]
+en: 2 is even
+fr: 4 est pair
+accumSum (0+2+4) [5]
+en: 5 is odd
+fr: 5 est impair
+accumSum (0+2+4) []
+l == []
+0+2+4
+0+6
+6
+
+
+en: Coming from an imperative language all should seem right.
+en: In fact, many things can be improved here.
+en: First, we can generalize the type.
+fr: En venant d'un langage impératif, tout devrait vous sembler juste.
+fr: En fait, beaucoup de choses peuvent être améliorées ici.
+fr: Tout d'abord, nous pouvons généraliser le type.
+
+
+evenSum :: Integral a => [a] -> a
+
+
+
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/12_Functions.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/12_Functions.lhs
new file mode 100644
index 0000000..8907b1e
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/12_Functions.lhs
@@ -0,0 +1,23 @@
+en: Next, we can use sub functions using `where` or `let`.
+fr: Ensuite, nous pouvons utiliser des sous-fonctions grâce à `where` et `let`.
+en: This way our `accumSum` function won't pollute the namespace of our module.
+fr: Ansi, notre fonction `accumSum` ne polluera pas le _namespace_ de notre module
+
+> -- Version 2
+> evenSum :: Integral a => [a] -> a
+>
+> evenSum l = accumSum 0 l
+> where accumSum n l =
+> if l == []
+> then n
+> else let x = head l
+> xs = tail l
+> in if even x
+> then accumSum (n+x) xs
+> else accumSum n xs
+
+
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/13_Functions.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/13_Functions.lhs
new file mode 100644
index 0000000..a2849c4
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/13_Functions.lhs
@@ -0,0 +1,64 @@
+en: Next, we can use pattern matching.
+fr: Puis on utilise le _pattern matching_
+
+> -- Version 3
+> evenSum l = accumSum 0 l
+> where
+> accumSum n [] = n
+> accumSum n (x:xs) =
+> if even x
+> then accumSum (n+x) xs
+> else accumSum n xs
+
+en: What is pattern matching?
+en: Use values instead of general parameter names[^021301].
+fr: Qu'est ce que le _pattern matching_ ?
+fr: Il s'agit d'utiliser des valeurs au lieu de noms de paramètres généraux.
+
+en: [^021301]: For the brave, a more complete explanation of pattern matching can be found [here](http://www.cs.auckland.ac.nz/references/haskell/haskell-intro-html/patterns.html).
+fr: [^021301]: Pour les plus courageux, une explication plus complète du _pattern matching_ peut être trouvée [ici](http://www.cs.auckland.ac.nz/references/haskell/haskell-intro-html/patterns.html) (_NdT: En anglais_)
+
+en: Instead of saying: `foo l = if l == [] then
+foo [] =
+
+en: But pattern matching goes even further.
+en: It is also able to inspect the inner data of a complex value.
+en: We can replace
+fr: Mais le _pattern matching_ peut aller encore plus loin.
+fr: Il est également capable d'inspect les données internes d'un valeur complexe.
+fr: Nous pouvons ainsi remplacer
+
+
+foo l = let x = head l
+ xs = tail l
+ in if even x
+ then foo (n+x) xs
+ else foo n xs
+
+
+en: with
+fr: par
+
+
+foo (x:xs) = if even x
+ then foo (n+x) xs
+ else foo n xs
+
+
+en: This is a very useful feature.
+en: It makes our code both terser and easier to read.
+fr: C'est une caractéristique très utile.
+fr: Notre code est ainsi plus concis et plus facile à lire.
+
+
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/14_Functions.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/14_Functions.lhs
new file mode 100644
index 0000000..9a92064
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/14_Functions.lhs
@@ -0,0 +1,37 @@
+en: In Haskell you can simplify function definitions by η-reducing them.
+en: For example, instead of writing:
+fr: Avec Haskell, nous pouvons simplifier les défitions des fonctions en les _η-réduisant_ .
+fr: Par exemple, au lieu d'écrire:
+
+
+en: f x = (some expresion) x
+fr: f x = (expression) x
+
+
+en: you can simply write
+fr: Nous pouvons écrire
+
+
+en: f = some expression
+fr: f = expression
+
+
+en: We use this method to remove the `l`:
+fr: Utilisons cette méthode pour retirer le `l`:
+
+> -- Version 4
+> evenSum :: Integral a => [a] -> a
+>
+> evenSum = accumSum 0
+> where
+> accumSum n [] = n
+> accumSum n (x:xs) =
+> if even x
+> then accumSum (n+x) xs
+> else accumSum n xs
+
+
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/15_Functions.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/15_Functions.lhs
new file mode 100644
index 0000000..6007a34
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/15_Functions.lhs
@@ -0,0 +1,123 @@
+en: Higher Order Functions
+fr: Fonctions d'ordre supérieur
+
+blogimage("escher_polygon.png","Escher")
+
+en: To make things even better we should use higher order functions.
+en: What are these beasts?
+en: Higher order functions are functions taking functions as parameters.
+fr: Pour rendre les choses plus faciles, nous devrions utiliser des fonctions d'ordre supérieur.
+fr: Ce sont des fonctions qui prennent des fonctions en paramètres
+
+en: Here are some examples:
+fr: Voici quelques exemples:
+
+
+filter :: (a -> Bool) -> [a] -> [a]
+map :: (a -> b) -> [a] -> [b]
+foldl :: (a -> b -> a) -> a -> [b] -> a
+
+
+en: Let's proceed by small steps.
+fr: Procédons par étapes.
+
+
+-- Version 5
+evenSum l = mysum 0 (filter even l)
+ where
+ mysum n [] = n
+ mysum n (x:xs) = mysum (n+x) xs
+
+
+en: where
+fr: où
+
+
+filter even [1..10] ⇔ [2,4,6,8,10]
+
+
+en: The function `filter` takes a function of type (`a -> Bool`) and a list of type `[a]`.
+en: It returns a list containing only elements for which the function returned `true`.
+fr: La fonction `filter` prend une fonction du type (`a -> Bool`) et une liste de type `[a]`.
+fr: Elle retourne une liste qui contient seulement les élements pour qui la fonction a retourné `True`.
+
+en: Our next step is to use another technique to accomplish the same thing as a loop.
+en: We will use the `foldl` function to accumulate a value as we pass through the list.
+en: The function `foldl` captures a general coding pattern:
+fr: La prochaine étape est d'utiliser une autre technique pour accomplir la même chose qu'une boucle.
+fr: Nous allons utiliser la fonction `foldl` pour accumuler une valeur au fur et à mesure que l'on parcoure la liste.
+fr: La fonction `foldl` capture un modèle de code général:
+
+
+ myfunc list = foo initialValue list
+ foo accumulated [] = accumulated
+ foo tmpValue (x:xs) = foo (bar tmpValue x) xs
+
+
+en: Which can be replaced by:
+fr: Qui peut être remplacé par:
+
+
+myfunc list = foldl bar initialValue list
+
+
+en: If you really want to know how the magic works, here is the definition of `foldl`:
+fr: Si vous souhaitez vraiment savoir comment la magie se produit, voici la définition de `foldl`:
+
+
+foldl f z [] = z
+foldl f z (x:xs) = foldl f (f z x) xs
+
+
+
+foldl f z [x1,...xn]
+⇔ f (... (f (f z x1) x2) ...) xn
+
+
+en: But as Haskell is lazy, it doesn't evaluate `(f z x)` and simply pushes it onto the stack.
+en: This is why we generally use `foldl'` instead of `foldl`;
+en: `foldl'` is a _strict_ version of `foldl`.
+en: If you don't understand what lazy and strict means,
+en: don't worry, just follow the code as if `foldl` and `foldl'` were identical.
+fr: Mais comme Haskell est paresseux, il n'évalue pas `(f z x)` et le met simplement dans la pile.
+fr: C'est pourquoi on utilise généralement `foldl'`, une version _stricte_ de `foldl`,
+fr: Si vous ne comprenez pas encore ce que _paresseux_ ou _strict_ signifie,
+fr: ne vous inquiétez pas, suivez le code comme si `foldl'` et `foldl` étaient identiques
+
+en: Now our new version of `evenSum` becomes:
+fr: Maintenant notre version de `evenSum` devient:
+
+
+-- Version 6
+en: -- foldl' isn't accessible by default
+en: -- we need to import it from the module Data.List
+fr: -- foldl' n'est pas accessible par défaut
+fr: -- nous devons l'importer depuis le module Data.List
+import Data.List
+evenSum l = foldl' mysum 0 (filter even l)
+ where mysum acc value = acc + value
+
+
+en: We can also simplify this by using directly a lambda notation.
+en: This way we don't have to create the temporary name `mysum`.
+fr: Nous pouvons aussi simplifier cela en utilisant une _lambda-notation_.
+fr: Ainsi nous n'avons pas besoin de créer le nom temporaire `mySum`.
+
+> -- Version 7
+> -- Generally it is considered a good practice
+> -- to import only the necessary function(s)
+> import Data.List (foldl')
+> evenSum l = foldl' (\x y -> x+y) 0 (filter even l)
+
+en: And of course, we note that
+fr: Et bien sûr, nous remarquons que
+
+
+(\x y -> x+y) ⇔ (+)
+
+
+
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/16_Functions.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/16_Functions.lhs
new file mode 100644
index 0000000..fc1c1c1
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/16_Functions.lhs
@@ -0,0 +1,148 @@
+en: Finally
+fr: Finalement
+
+
+-- Version 8
+import Data.List (foldl')
+evenSum :: Integral a => [a] -> a
+evenSum l = foldl' (+) 0 (filter even l)
+
+
+en: `foldl'` isn't the easiest function to grasp.
+en: If you are not used to it, you should study it a bit.
+fr: `foldl'` n'est pas la fonction la plus facile à prendre en main.
+fr: Si vous n'y êtes pas habitué, vous devriez l'étudier un peu.
+
+en: To help you understand what's going on here, let's look at a step by step evaluation:
+fr: Pour mieux comprendre ce qui se passe ici, étudions une évaluation étape par étape:
+
+
+ evenSum [1,2,3,4]
+⇒ foldl' (+) 0 (filter even [1,2,3,4])
+⇒ foldl' (+) 0 [2,4]
+⇒ foldl' (+) (0+2) [4]
+⇒ foldl' (+) 2 [4]
+⇒ foldl' (+) (2+4) []
+⇒ foldl' (+) 6 []
+⇒ 6
+
+
+
+en: Another useful higher order function is `(.)`.
+en: The `(.)` function corresponds to mathematical composition.
+fr: Une autre fonction d'ordre supérieur utile est `(.)`.
+fr: Elle correspond à une composition en mathématiques.
+
+
+(f . g . h) x ⇔ f ( g (h x))
+
+
+en: We can take advantage of this operator to η-reduce our function:
+fr: Nous pouvons profiter de cet opérateur pour η-réduire notre fonction:
+
+
+-- Version 9
+import Data.List (foldl')
+evenSum :: Integral a => [a] -> a
+evenSum = (foldl' (+) 0) . (filter even)
+
+
+en: Also, we could rename some parts to make it clearer:
+fr: Nous pouvons maintenant renommer certaines parties pour rendre le tout plus clair:
+
+> -- Version 10
+> import Data.List (foldl')
+> sum' :: (Num a) => [a] -> a
+> sum' = foldl' (+) 0
+> evenSum :: Integral a => [a] -> a
+> evenSum = sum' . (filter even)
+>
+
+en: It is time to discuss the direction our code has moved as we introduced more functional idioms.
+en: What did we gain by using higher order functions?
+fr: Il est temps de discuter de la direction qu'a pris notre code depuis que nous avons introduit plus d'idiomes fonctionnels.
+fr: Que gagnons-nous à utiliser des fonctions d'ordre supérieur?
+
+en: At first, you might think the main difference is terseness. But in fact, it has
+en: more to do with better thinking. Suppose we want to modify our function
+en: slightly, for example, to get the sum of all even squares of elements of the list.
+fr: D'abord, vous pourriez penser que la principale différence est la brièveté. Mais en réalité,
+fr: il s'agit d'une meilleure façon de penser. Supposons que nous voulons modifier légèrement notre fonction,
+fr: par exemple, pour qu'elle renvoie la somme de tous les carrés pairs des éléments de la liste.
+
+~~~
+[1,2,3,4] ▷ [1,4,9,16] ▷ [4,16] ▷ 20
+~~~
+
+en: Updating version 10 is extremely easy:
+fr: Mettre la version 10 à jour est très facile:
+
+> squareEvenSum = sum' . (filter even) . (map (^2))
+> squareEvenSum' = evenSum . (map (^2))
+
+en: We just had to add another "transformation function"[^0216].
+fr: Nous avons juste eu à ajouter une autre "fonction de trabsformation"[^0216].
+
+~~~
+map (^2) [1,2,3,4] ⇔ [1,4,9,16]
+~~~
+
+en: The `map` function simply applies a function to all the elements of a list.
+fr: La fonction `map` applique simplementune fonction à tous les élements d'une liste.
+
+en: We didn't have to modify anything _inside_ the function definition.
+en: This makes the code more modular.
+en: But in addition you can think more mathematically about your function.
+en: You can also use your function interchangably with others, as needed.
+en: That is, you can compose, map, fold, filter using your new function.
+fr: Nous n'avons rien modifié _à l'intérieur_ de notre définition de fonction.
+fr: Cela rend le code plus modulaire.
+fr: En plus de cela, vous pouvez penser à votre fonction plus mathématiquement.
+fr: Vous pouvez aussi utilier votre fonction avec d'autres, au besoin:
+fr: vous pouvez utiliser `compose`, `map`, `fold` ou `filter` sur notre nouvelle fonction.
+
+en: Modifying version 1 is left as an exercise to the reader ☺.
+fr: Modifier la version 1 est laissé comme un exercice pour le lecteur ☺.
+
+en: If you believe we have reached the end of generalization, then know you are very wrong.
+en: For example, there is a way to not only use this function on lists but on any recursive type.
+en: If you want to know how, I suggest you to read this quite fun article: [Functional Programming with Bananas, Lenses, Envelopes and Barbed Wire by Meijer, Fokkinga and Paterson](http://eprints.eemcs.utwente.nl/7281/01/db-utwente-40501F46.pdf).
+fr: Si vous croyez avoir atteint le bout de la généralisation, vous avez tout faux.
+fr: Par example, il y a un moyen d'utiliser cette fonction non seulement sur les listes mais aussi sur n'importe quel type récursif.
+fr: Si vous voulez savoir comment, je vous suggère de lire cet article: [Functional Programming with Bananas, Lenses, Envelopes and Barbed Wire by Meijer, Fokkinga and Paterson](http://eprints.eemcs.utwente.nl/7281/01/db-utwente-40501F46.pdf) (_NDT: en anglais, mais là vous vous en seriez douté je pense ☺_)
+
+en: This example should show you how great pure functional programming is.
+en: Unfortunately, using pure functional programming isn't well suited to all usages.
+en: Or at least such a language hasn't been found yet.
+fr: Cet exemple montre à quel point la programmation fonctionnelle pure est géniale.
+fr: Malheureusement, utiliser cet outil n'est pas adapté à tous les besoins.
+fr: Ou alors un langage qui le premettrait n'a pas encore été trouvé.
+
+en: One of the great powers of Haskell is the ability to create DSLs
+en: (Domain Specific Language)
+en: making it easy to change the programming paradigm.
+fr: Une des grands pouvoirs de Haskell est sa capacité à créer des DSLs
+fr: (_Domain Specific Language_, en français : _langage spécifique à un domaine_)
+fr: Il est ainsi facile de changer le pardigme de programmation
+
+en: In fact, Haskell is also great when you want to write imperative style
+en: programming. Understanding this was really hard for me to grasp when first
+en: learning Haskell. A lot of effort tends to go into explaining the superiority
+en: of the functional approach. Then when you start using an imperative style with
+en: Haskell, it can be hard to understand when and how to use it.
+fr: En fait, Haskell peut très bien vous permettre d'écrire des programmes impératifs.
+fr: Comprendre cela a été très difficile pour moi lorsque j'apprenais Haskell.
+fr: Beaucoup d'efforts tendent à expliquer la supériorité de l'approche fonctionnele.
+fr: Puis lorsque vous commencez à utliser le style impératif en Haskell,
+fr: Il peut être difficile de comprendre quand et où l'utliser.
+
+en: But before talking about this Haskell super-power, we must talk about another
+en: essential aspect of Haskell: _Types_.
+fr: Mais avant de parler de ce super-pouvoir de Haskell, nous devons parler
+fr: d'un autre aspet essentiel: les _Types_.
+
+
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/20_Types.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/20_Types.lhs
new file mode 100644
index 0000000..175db29
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/20_Types.lhs
@@ -0,0 +1,137 @@
+en: Types
+fr: Les types
+
+blogimage("salvador-dali-the-madonna-of-port-lligat.jpg","Dali, the madonna of port Lligat")
+
+ > %tldr
+ >
+ > - `type Name = AnotherType` is just an alias and the compiler doesn't mark any difference between `Name` and `AnotherType`.
+ > - `data Name = NameConstructor AnotherType` does mark a difference.
+ > - `data` can construct structures which can be recursives.
+ > - `deriving` is magic and creates functions for you.
+
+en: In Haskell, types are strong and static.
+fr: En Haskell, les types sont forts et statiques.
+
+en: Why is this important? It will help you _greatly_ to avoid mistakes.
+en: In Haskell, most bugs are caught during the compilation of your program.
+en: And the main reason is because of the type inference during compilation.
+en: Type inference makes it easy to detect where you used the wrong parameter at the wrong place, for example.
+fr: Pourquoi est-ce important? Cela vous aidera a éviter _beaucoup_ d'erreurs.
+fr: En Haskell, la majorité des bugs est repérée durant la compilation de votre programme.
+fr: Et la raison principale de cela est l'inférence de type durant la compilation.
+fr: L'inférence de type permet de détecter plus facilement lorsque vous utilisez le mauvais paramètre au mauvais endroit, par exemple
+
+en: Type inference
+fr: Inférence de type
+
+en: Static typing is generally essential for fast execution.
+en: But most statically typed languages are bad at generalizing concepts.
+en: Haskell's saving grace is that it can _infer_ types.
+fr: Le typage statique est généralement essentiel pour une exécution rapide.
+fr: Mais la plupart des langages typés statiquement ont du mal à généraliser des concepts.
+fr: La "grâce salvatrice" de Haskell est qu'il peut _inférer_ des types.
+
+en: Here is a simple example, the `square` function in Haskell:
+fr: Voici un exemple simple, la fonction `square` en Haskell:
+
+
+square x = x * x
+
+
+en: This function can `square` any Numeral type.
+en: You can provide `square` with an `Int`, an `Integer`, a `Float` a `Fractional` and even `Complex`. Proof by example:
+fr: Cette fonction peut mettre au carré n'importe quel type `Numeral`.
+fr: Vous pouvez l'utilser avec un `Int`, un `Integer`, un `Float`, un `Fractional` ou même un `Complex`. Preuve par l'exemple:
+
+~~~
+% ghci
+GHCi, version 7.0.4:
+...
+Prelude> let square x = x*x
+Prelude> square 2
+4
+Prelude> square 2.1
+4.41
+en: Prelude> -- load the Data.Complex module
+fr: Prelude> -- charge le module Data.Complex
+Prelude> :m Data.Complex
+Prelude Data.Complex> square (2 :+ 1)
+3.0 :+ 4.0
+~~~
+
+en: `x :+ y` is the notation for the complex (x + iy).
+fr: `x :+ y` est la notation pour le complexe (x + iy)
+
+en: Now compare with the amount of code necessary in C:
+fr: Comparons maintenant avec la quantité de code nécessaire pour le faire en C:
+
+
+int int_square(int x) { return x*x; }
+
+float float_square(float x) {return x*x; }
+
+complex complex_square (complex z) {
+ complex tmp;
+ tmp.real = z.real * z.real - z.img * z.img;
+ tmp.img = 2 * z.img * z.real;
+}
+
+complex x,y;
+y = complex_square(x);
+
+
+en: For each type, you need to write a new function.
+en: The only way to work around this problem is to use some meta-programming trick, for example using the pre-processor.
+en: In C++ there is a better way, C++ templates:
+fr: Pour chaque type, vous avez besoin d'écrire une nouvelle fonction.
+fr: Le seul moyen de se débarrasser de ce problème est d'utiliser des astuces de méta-programmation, par exemple en utilisant le pré-processeur.
+fr: en C++ il y a un meilleur moyen, les _templates_:
+
+
+#include
+
+en: C++ does a far better job than C in this regard.
+en: But for more complex functions the syntax can be hard to follow:
+en: see [this article](http://bartoszmilewski.com/2009/10/21/what-does-haskell-have-to-do-with-c/) for example.
+fr: C++ fait un bien meilleur travail que C ici.
+fr: Mais pour des fonctions plus complexes, la syntaxe sera difficile à suivre.
+fr: Voyez [cet article](http://bartoszmilewski.com/2009/10/21/what-does-haskell-have-to-do-with-c/) pour quelques exemples. (_NDT: toujours en anglais)
+
+en: In C++ you must declare that a function can work with different types.
+en: In Haskell, the opposite is the case.
+en: The function will be as general as possible by default.
+fr: En C++ vous devez déclarer qu'une fonction peut marcher avec différents types.
+fr: En Haskell, c'est le contraire.
+fr: La fonction sera aussi générale que possible par défaut.
+
+en: Type inference gives Haskell the feeling of freedom that dynamically typed languages provide.
+en: But unlike dynamically typed languages, most errors are caught before run time.
+en: Generally, in Haskell:
+fr: L'inférence de type donne à Haskell le sentiment de liberté que les langages dynamiquement typés proposent.
+fr: Mais contrairement aux langages dynamiquement typés, la majorité des erreurs est détectée avant de lancer le programme.
+fr: Généralement, en Haskell:
+
+en: > "if it compiles it certainly does what you intended"
+fr: > "Si ça compile, ça fait certainement ce que vous attendiez."
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/21_Types.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/21_Types.lhs
new file mode 100644
index 0000000..8bfb530
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/21_Types.lhs
@@ -0,0 +1,19 @@
+en: Type construction
+fr: Construction de types
+
+en: You can construct your own types.
+en: First, you can use aliases or type synonyms.
+fr: Vous pouvez construire vos propres types.
+fr: D'abord, vous pouvez utiliser des alias ou des synonymes de types.
+
+> type Name = String
+> type Color = String
+>
+> showInfos :: Name -> Color -> String
+> showInfos name color = "Name: " ++ name
+> ++ ", Color: " ++ color
+> name :: Name
+> name = "Robin"
+> color :: Color
+> color = "Blue"
+> main = putStrLn $ showInfos name color
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/22_Types.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/22_Types.lhs
new file mode 100644
index 0000000..e41679b
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/22_Types.lhs
@@ -0,0 +1,90 @@
+
+en: But it doesn't protect you much.
+en: Try to swap the two parameter of `showInfos` and run the program:
+fr: Mais cela ne vous protège pas tellement.
+fr: Essayez d'inverser les deux paramètres de `showInfos` et lancez le programme:
+
+
+ putStrLn $ showInfos color name
+
+
+en: It will compile and execute.
+en: In fact you can replace Name, Color and String everywhere.
+en: The compiler will treat them as completely identical.
+fr: Le code sera compilé et exécuté.
+fr: En fait vous pouvez remplace Name, Color et String n'importe où.
+fr: Le compilateur les traitera comme si ils était complétement identiques.
+
+en: Another method is to create your own types using the keyword `data`.
+fr: Une autre méthode est de créer vos propres type avec le mot-clé `data`.
+
+> data Name = NameConstr String
+> data Color = ColorConstr String
+>
+> showInfos :: Name -> Color -> String
+> showInfos (NameConstr name) (ColorConstr color) =
+> "Name: " ++ name ++ ", Color: " ++ color
+>
+> name = NameConstr "Robin"
+> color = ColorConstr "Blue"
+> main = putStrLn $ showInfos name color
+
+en: Now if you switch parameters of `showInfos`, the compiler complains!
+en: So this is a potential mistake you will never make again and the only price is to be more verbose.
+fr: Maintenant, si vous échangez les paramètres de `showInfos`, le compilateur se plaint!
+fr: Au seul prix d'être plus verbeux, vous écartez définitivement cette erreur potentielle.
+
+en: Also notice that constructors are functions:
+fr: Remarquez aussi que les constructeurs sont des fonctions :
+
+
+NameConstr :: String -> Name
+ColorConstr :: String -> Color
+
+
+en: The syntax of `data` is mainly:
+fr: La syntaxe de `data` est principalement:
+
+
+data TypeName = ConstructorName [types]
+ | ConstructorName2 [types]
+ | ...
+
+
+en: Generally the usage is to use the same name for the
+en: DataTypeName and DataTypeConstructor.
+fr: Généralement on utilise le même nom pour le DatatTypeName et le DataTypeConstructor.
+
+en: Example:
+fr: Exemple :
+
+
+data Complex a = Num a => Complex a a
+
+
+en: Also you can use the record syntax:
+fr: Vous pouvez également utiliser cette syntaxe :
+
+
+data DataTypeName = DataConstructor {
+ field1 :: [type of field1]
+ , field2 :: [type of field2]
+ ...
+ , fieldn :: [type of fieldn] }
+
+
+en: And many accessors are made for you.
+en: Furthermore you can use another order when setting values.
+fr: Et de nombreux accesseurs sont définis pour vous.
+fr: En outre, vous pouvez utiliser une autre ordre lorsque vous définissez des valeurs.
+
+en: Example:
+fr: Exemple :
+
+
+data Complex a = Num a => Complex { real :: a, img :: a}
+c = Complex 1.0 2.0
+z = Complex { real = 3, img = 4 }
+real c ⇒ 1.0
+img z ⇒ 4
+
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/23_Types.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/23_Types.lhs
new file mode 100644
index 0000000..38de0c0
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/23_Types.lhs
@@ -0,0 +1,50 @@
+en: Recursive type
+fr: Type récursif
+
+en: You already encountered a recursive type: lists.
+en: You can re-create lists, but with a more verbose syntax:
+fr: Nous avons déjà rencontré un type récursif : les listes.
+fr: Nous pourrions re-créer les listes, avec une syntaxe plus bavarde:
+
+
+data List a = Empty | Cons a (List a)
+
+
+
+en: If you really want to use an easier syntax you can use an infix name for constructors.
+fr: Si vous voulez réellement utiliser une syntxe plus simple, utilisez un nom infixe pour les constructeurs.
+
+
+infixr 5 :::
+data List a = Nil | a ::: (List a)
+
+
+en: The number after `infixr` gives the precedence.
+fr: Le nombre après `infixr` donne la priorité.
+
+en: If you want to be able to print (`Show`), read (`Read`), test equality (`Eq`) and compare (`Ord`) your new data structure you can tell Haskell to derive the appropriate functions for you.
+fr: Si vous voulez pouvoir écrire (`Show`), lire (`Read`), tester l'égalité (`Eq`) et comparer (`Ord`) votre nouvelle structure, vous pouvez demander à Haskell de dériver les fonctions appropriées pour vous.
+
+> infixr 5 :::
+> data List a = Nil | a ::: (List a)
+> deriving (Show,Read,Eq,Ord)
+
+en: When you add `deriving (Show)` to your data declaration, Haskell creates a `show` function for you.
+en: We'll see soon how you can use your own `show` function.
+fr: Quand vous ajoutez `deriving (Show)` à votre déclaration, Haskell crée une fonction `show` pour vous.
+fr: Nous verrons bientôt comment utiliser sa propre fonction `show`.
+
+> convertList [] = Nil
+> convertList (x:xs) = x ::: convertList xs
+
+> main = do
+> print (0 ::: 1 ::: Nil)
+> print (convertList [0,1])
+
+en: This prints:
+fr: Ceci donne :
+
+~~~
+0 ::: (1 ::: Nil)
+0 ::: (1 ::: Nil)
+~~~
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/30_Trees.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/30_Trees.lhs
new file mode 100644
index 0000000..3441406
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/30_Trees.lhs
@@ -0,0 +1,49 @@
+en: Trees
+fr: Les arbres
+
+blogimage("magritte-l-arbre.jpg","Magritte, l'Arbre")
+
+en: We'll just give another standard example: binary trees.
+fr: Voici une autre exemple standard : les arbres binaires.
+
+> import Data.List
+>
+> data BinTree a = Empty
+> | Node a (BinTree a) (BinTree a)
+> deriving (Show)
+
+en: We will also create a function which turns a list into an ordered binary tree.
+fr: Créons aussi une fonctions qui transforme une liste en un arbre binaire ordonné.
+
+> treeFromList :: (Ord a) => [a] -> BinTree a
+> treeFromList [] = Empty
+> treeFromList (x:xs) = Node x (treeFromList (filter (
+instance Show (BinTree a) where
+en: show t = ... -- You declare your function here
+fr: show t = ... -- Déclarez votre fonction ici
+
+
+en: Here is my version of how to show a binary tree.
+en: Don't worry about the apparent complexity.
+en: I made a lot of improvements in order to display even stranger objects.
+fr: Voici ma version pour afficher un arbre binaire.
+fr: Ne vous inquiétez pas de sa complexité apparente.
+fr: J'ai fait beaucoup d'améliorations pour afficher même les objets les plus étranges.
+
+> -- declare BinTree a to be an instance of Show
+> instance (Show a) => Show (BinTree a) where
+> -- will start by a '<' before the root
+> -- and put a : a begining of line
+> show t = "< " ++ replace '\n' "\n: " (treeshow "" t)
+> where
+> -- treeshow pref Tree
+> -- shows a tree and starts each line with pref
+> -- We don't display the Empty tree
+> treeshow pref Empty = ""
+> -- Leaf
+> treeshow pref (Node x Empty Empty) =
+> (pshow pref x)
+>
+> -- Right branch is empty
+> treeshow pref (Node x left Empty) =
+> (pshow pref x) ++ "\n" ++
+> (showSon pref "`--" " " left)
+>
+> -- Left branch is empty
+> treeshow pref (Node x Empty right) =
+> (pshow pref x) ++ "\n" ++
+> (showSon pref "`--" " " right)
+>
+> -- Tree with left and right children non empty
+> treeshow pref (Node x left right) =
+> (pshow pref x) ++ "\n" ++
+> (showSon pref "|--" "| " left) ++ "\n" ++
+> (showSon pref "`--" " " right)
+>
+> -- shows a tree using some prefixes to make it nice
+> showSon pref before next t =
+> pref ++ before ++ treeshow (pref ++ next) t
+>
+> -- pshow replaces "\n" by "\n"++pref
+> pshow pref x = replace '\n' ("\n"++pref) (show x)
+>
+> -- replaces one char by another string
+> replace c new string =
+> concatMap (change c new) string
+> where
+> change c new x
+> | x == c = new
+> | otherwise = x:[] -- "x"
+
+
+en: The `treeFromList` method remains identical.
+fr: La méthode `treeFromList` reste identique.
+
+> treeFromList :: (Ord a) => [a] -> BinTree a
+> treeFromList [] = Empty
+> treeFromList (x:xs) = Node x (treeFromList (filter (
+print ( treeFromList (
+ map treeFromList
+ [ map treeFromList ["YO","DAWG"]
+ , map treeFromList ["I","HEARD"]
+ , map treeFromList ["I","HEARD"]
+ , map treeFromList ["YOU","LIKE","TREES"] ]))
+
+
+en: and gives:
+fr: et donne :
+
+~~~
+en: Binary tree of Binary trees of Char binary trees:
+fr: Arbre d'arbres d'arbres de Char :
+< < < 'Y'
+: : : `--'O'
+: : `--< 'D'
+: : : |--'A'
+: : : `--'W'
+: : : `--'G'
+: |--< < 'I'
+: | : `--< 'H'
+: | : : |--'E'
+: | : : | `--'A'
+: | : : | `--'D'
+: | : : `--'R'
+: `--< < 'Y'
+: : : `--'O'
+: : : `--'U'
+: : `--< 'L'
+: : : `--'I'
+: : : |--'E'
+: : : `--'K'
+: : `--< 'T'
+: : : `--'R'
+: : : |--'E'
+: : : `--'S'
+~~~
+
+en: Notice how duplicate trees aren't inserted;
+en: there is only one tree corresponding to `"I","HEARD"`.
+en: We have this for (almost) free, because we have declared Tree to be an instance of `Eq`.
+fr: Remarquez que les arbres en double ne sont pas insérés.
+fr: Il n'y a qu'un seul arbre correspondant à `"I","HEARD"`.
+fr: Nous avons ceci presque gratuitement, car nous avons déclaré Tree comme instance de `Eq`.
+
+en: See how awesome this structure is:
+en: We can make trees containing not only integers, strings and chars, but also other trees.
+en: And we can even make a tree containing a tree of trees!
+fr: Voyez à quel point cette structure est formidable :
+fr: Nous pouvons faire des arbres contenant seulement des entiers, des chaînes de caractères, mais aussi d'autres arbres.
+fr: Et nous pouvons même faire un arbre contenant un arbre d'arbres!
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/40_Infinites_Structures.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/40_Infinites_Structures.lhs
new file mode 100644
index 0000000..e8bf462
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/40_Infinites_Structures.lhs
@@ -0,0 +1,59 @@
+en: Infinite Structures
+fr: Structures infinies
+
+blogimage("escher_infinite_lizards.jpg","Escher")
+
+en: It is often said that Haskell is _lazy_.
+fr: On dit souvent que Haskell est _paresseux_.
+
+en: In fact, if you are a bit pedantic, you should say that [Haskell is _non-strict_](http://www.haskell.org/haskellwiki/Lazy_vs._non-strict).
+en: Laziness is just a common implementation for non-strict languages.
+fr: En fait, si vous êtes un petit peu pédant, vous devriez dire que [Haskell est _non-strict_](http://www.haskell.org/haskellwiki/Lazy_vs._non-strict) (_NDT: En anglais, pour changer_).
+fr: La paresse est juste une implémentation commune aux langages non-stricts.
+
+en: Then what does "not-strict" mean? From the Haskell wiki:
+fr: Alors que signifie "non-strict"? D'après le wiki de Haskell :
+
+en: > Reduction (the mathematical term for evaluation) proceeds from the outside in.
+en: >
+en: > so if you have `(a+(b*c))` then you first reduce `+` first, then you reduce the inner `(b*c)`
+fr: > La réduction (terme mathématique pour "évaluation") procède depuis l'extérieur.
+fr: >
+fr: > Donc si vous avez `(a+(b*c))`, alors vous réduisez `+` d'abord, puis vous réduisez `(b*c)`
+
+en: For example in Haskell you can do:
+fr: Par exemple en Haskell vous pouvez faire :
+
+> -- numbers = [1,2,..]
+> numbers :: [Integer]
+> numbers = 0:map (1+) numbers
+>
+> take' n [] = []
+> take' 0 l = []
+> take' n (x:xs) = x:take' (n-1) xs
+>
+> main = print $ take' 10 numbers
+
+en: And it stops.
+fr: Et ça s'arrête.
+
+en: How?
+fr: Comment ?
+
+en: Instead of trying to evaluate `numbers` entirely,
+en: it evaluates elements only when needed.
+fr: Au lieu d'essayer d'évaluer `numbers` entièrement,
+fr: Haskell évalue les éléments seulement lorsque c'est nécessaire.
+
+en: Also, note in Haskell there is a notation for infinite lists
+fr: Remarquez aussi qu'en Haskell, il y a une notation pour les listes infinies
+
+~~~
+[1..] ⇔ [1,2,3,4...]
+[1,3..] ⇔ [1,3,5,7,9,11...]
+~~~
+
+en: and most functions will work with them.
+en: Also, there is a built-in function `take` which is equivalent to our `take'`.
+fr: et que la majorité des fonctions fonctionnera avec ces listes.
+fr: Il y a aussi une fonction `take` équivalente à notre `take'`.
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/41_Infinites_Structures.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/41_Infinites_Structures.lhs
new file mode 100644
index 0000000..f8384ff
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/02_Hard_Part/41_Infinites_Structures.lhs
@@ -0,0 +1,173 @@
+
+
+
+en: Suppose we don't mind having an ordered binary tree.
+en: Here is an infinite binary tree:
+fr: Supposons que nous ne nous préoccupions pas d'avoir une arbre ordonné.
+fr: Voici un arbre binaire infini :
+
+> nullTree = Node 0 nullTree nullTree
+
+en: A complete binary tree where each node is equal to 0.
+en: Now I will prove you can manipulate this object using the following function:
+fr: Un arbre complet où chaque noeud est égal à 0.
+fr: Maintenant je vais vous prouver que nous pouvons manipuler cet arbre avec la fonction suivante :
+
+> -- take all element of a BinTree
+> -- up to some depth
+> treeTakeDepth _ Empty = Empty
+> treeTakeDepth 0 _ = Empty
+> treeTakeDepth n (Node x left right) = let
+> nl = treeTakeDepth (n-1) left
+> nr = treeTakeDepth (n-1) right
+> in
+> Node x nl nr
+
+en: See what occurs for this program:
+fr: Regardez ce qui se passe avec ce programme :
+
+
+main = print $ treeTakeDepth 4 nullTree
+
+
+en: This code compiles, runs and stops giving the following result:
+fr: Le code compile, se lance et s'arrête en donnant ce résultat :
+
+~~~
+< 0
+: |-- 0
+: | |-- 0
+: | | |-- 0
+: | | `-- 0
+: | `-- 0
+: | |-- 0
+: | `-- 0
+: `-- 0
+: |-- 0
+: | |-- 0
+: | `-- 0
+: `-- 0
+: |-- 0
+: `-- 0
+~~~
+
+en: Just to heat up your neurones a bit more,
+en: let's make a slightly more interesting tree:
+fr: Pour nous chauffer encore un peu les neurones,
+fr: faisons un arbre plus intéressant :
+
+> iTree = Node 0 (dec iTree) (inc iTree)
+> where
+> dec (Node x l r) = Node (x-1) (dec l) (dec r)
+> inc (Node x l r) = Node (x+1) (inc l) (inc r)
+
+en: Another way to create this tree is to use a higher order function.
+en: This function should be similar to `map`, but should work on `BinTree` instead of list.
+en: Here is such a function:
+fr: Un autre moyen de créer cet arbre est d'utiliser une fonction d'ordre supérieur.
+fr: Cette fonction devrait être similaire à `map` n, mais devrait travailler sur un `BinTree` au lieu d'une liste.
+fr: Voici cette fonction :
+
+> -- apply a function to each node of Tree
+> treeMap :: (a -> b) -> BinTree a -> BinTree b
+> treeMap f Empty = Empty
+> treeMap f (Node x left right) = Node (f x)
+> (treeMap f left)
+> (treeMap f right)
+
+en: _Hint_: I won't talk more about this here.
+en: If you are interested in the generalization of `map` to other data structures,
+en: search for functor and `fmap`.
+fr: _NB_: Je ne parlerai pas plus de cette fonction ici.
+fr: Si vous vous intéressez à la généralisation de `map` à d'autres structures de données,
+fr: cherchez des informations sur les foncteurs et `fmap`.
+
+en: Our definition is now:
+fr: Notre définition est maintenant :
+
+> infTreeTwo :: BinTree Int
+> infTreeTwo = Node 0 (treeMap (\x -> x-1) infTreeTwo)
+> (treeMap (\x -> x+1) infTreeTwo)
+
+en: Look at the result for
+fr: Regardez le résultat pour
+
+
+main = print $ treeTakeDepth 4 infTreeTwo
+
+
+~~~
+< 0
+: |-- -1
+: | |-- -2
+: | | |-- -3
+: | | `-- -1
+: | `-- 0
+: | |-- -1
+: | `-- 1
+: `-- 1
+: |-- 0
+: | |-- -1
+: | `-- 1
+: `-- 2
+: |-- 1
+: `-- 3
+~~~
+
+
+
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/00_Introduction.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/00_Introduction.lhs
new file mode 100644
index 0000000..7186e7a
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/00_Introduction.lhs
@@ -0,0 +1,28 @@
+en: Hell Difficulty Part
+fr: Partie de difficulté infernale
+
+en: Congratulations for getting so far!
+en: Now, some of the really hardcore stuff can start.
+fr: Félicitations pour être allé si loin!
+fr: Maitenant, les choses vraiment extrêmes peuvent commencer.
+
+en: If you are like me, you should get the functional style.
+en: You should also understand a bit more the advantages of laziness by default.
+en: But you also don't really understand where to start in order to make a real
+en: program.
+en: And in particular:
+fr: Si vous êtes comme moi, vous êtes déjà familier avec le style fonctionnel.
+fr: Vous devriez également comprendre les avantages de la paresse par défaut.
+fr: Mais vous ne comprenez peut-être pas vraiment par où commencer pour faire un vrai
+fr: programme.
+fr: Et en particulier :
+
+en: - How do you deal with effects?
+en: - Why is there a strange imperative-like notation for dealing with IO?
+fr: - Comment s'occuper des effets ?
+fr: - Pourquoi y a t-il une étrange notation impérative lorsque l'on s'occupe de l'Entrée/Sortie? (E/S, _IO_ pour _Input/Output_ en anglais)
+
+en: Be prepared, the answers might be complex.
+en: But they are all very rewarding.
+fr: Accrochez-vous, les réponses risquent d'être compliquées.
+fr: Mais elles en valent la peine.
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/01_IO/01_progressive_io_example.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/01_IO/01_progressive_io_example.lhs
new file mode 100644
index 0000000..5d64772
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/01_IO/01_progressive_io_example.lhs
@@ -0,0 +1,117 @@
+en: Deal With IO
+fr: S'occuper de l'E/S (IO)
+
+blogimage("magritte_carte_blanche.jpg","Magritte, Carte blanche")
+
+ > %tldr
+ >
+en: > A typical function doing `IO` looks a lot like an imperative program:
+fr: > Une fonction typique qui fait de l'`IO` ressemble à un programme impératif:
+ >
+ > ~~~
+ > f :: IO a
+ > f = do
+ > x <- action1
+ > action2 x
+ > y <- action3
+ > action4 x y
+ > ~~~
+ >
+en: > - To set a value to an object we use `<-` .
+en: > - The type of each line is `IO *`;
+en: > in this example:
+fr: > - Pour définir la valeur d'un objet on utilise `<-` .
+fr: > - Le type de chaque ligne est `IO *`;
+fr: > dans cet exemple:
+ > - `action1 :: IO b`
+ > - `action2 x :: IO ()`
+ > - `action3 :: IO c`
+ > - `action4 x y :: IO a`
+ > - `x :: b`, `y :: c`
+en: > - Few objects have the type `IO a`, this should help you choose.
+en: > In particular you cannot use pure functions directly here.
+en: > To use pure functions you could do `action2 (purefunction x)` for example.
+fr: > - Quelques objets ont le type `IO a`, cela devrait vous aider à choisir.
+fr: > En particulier vous ne pouvez pas utiliser de fonctions pures directement ici.
+fr: > Pour utiliser des fonctions pures vous pourriez faire `action2 (pureFunction x)` par exemple.
+
+en: In this section, I will explain how to use IO, not how it works.
+en: You'll see how Haskell separates the pure from the impure parts of the program.
+fr: Dans cette section, je vais expliquer comment utiliser l'IO, pas comment ça marche.
+fr: Vous verrez comment Haskell sépare les parties pures et impures du programme.
+
+en: Don't stop because you're trying to understand the details of the syntax.
+en: Answers will come in the next section.
+fr: Ne vous arrêtez pas sur les détails de la syntaxe
+fr: Les réponses viendront dans la section suivante.
+
+en: What to achieve?
+fr: Que cherchons-nous à faire?
+
+en: > Ask a user to enter a list of numbers.
+en: > Print the sum of the numbers
+fr: > Demander une liste de nombres à l'utilisateur.
+fr: > Afficher la somme de ces nombres.
+
+> toList :: String -> [Integer]
+> toList input = read ("[" ++ input ++ "]")
+>
+> main = do
+> putStrLn "Enter a list of numbers (separated by comma):"
+> input <- getLine
+> print $ sum (toList input)
+
+en: It should be straightforward to understand the behavior of this program.
+en: Let's analyze the types in more detail.
+fr: Il devrait être simple de comprendre le comportement de ce programme.
+fr: Analysons les types en détails.
+
+~~~
+putStrLn :: String -> IO ()
+getLine :: IO String
+print :: Show a => a -> IO ()
+~~~
+
+en: Or more interestingly, we note that each expression in the `do` block has a type of `IO a`.
+fr: Ou, de manièree plus intéressante, on remarque que chaque expression dans le bloc `do` est de type `IO a`.
+
+
+main = do
+ putStrLn "Enter ... " :: IO ()
+ getLine :: IO String
+ print Something :: IO ()
+
+
+en: We should also pay attention to the effect of the `<-` symbol.
+fr: Nous devrions aussi prêter attention à l'effet du symbole `<-`.
+
+~~~
+do
+ x <- something
+~~~
+
+en: If `something :: IO a` then `x :: a`.
+fr: Si `something :: IO a` alors `x :: a`.
+
+en: Another important note about using `IO`:
+en: All lines in a do block must be of one of the two forms:
+fr: Une autre remarque importante sur l'`IO`:
+fr: Toutes les lignes d'un bloc `do` doivent être d'une des deux formes suivantes :
+
+~~~
+action1 :: IO a
+ -- in this case, generally a = ()
+~~~
+
+ou
+
+~~~
+value <- action2 -- where
+ -- action2 :: IO b
+ -- value :: b
+~~~
+
+en: These two kinds of line will correspond to two different ways of sequencing actions.
+en: The meaning of this sentence should be clearer by the end of the next section.
+fr: Ces deux types de ligne correspondent à deux types différents de séquençage d'action.
+fr: La signification de cette phrase devrait être plus claire à la fin de la prochaine section.
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/01_IO/02_progressive_io_example.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/01_IO/02_progressive_io_example.lhs
new file mode 100644
index 0000000..4feec04
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/01_IO/02_progressive_io_example.lhs
@@ -0,0 +1,123 @@
+en: Now let's see how this program behaves.
+en: For example, what happens if the user enters something strange?
+en: Let's try:
+fr: Maintenant voyons comment ce programme se comporte.
+fr: Par exemple, que ce passe-t-il si l'utilisateur entre une mauvaise valeur?
+fr: Essayons :
+
+~~~
+ % runghc 02_progressive_io_example.lhs
+ Enter a list of numbers (separated by comma):
+ foo
+ Prelude.read: no parse
+~~~
+
+
+en: Argh! An evil error message and a crash!
+fr: Argh! Un message d'erreur effrayant et un crash !
+en: Our first improvement will simply be to answer with a more friendly message.
+fr: Notre première amélioration sera de répondre avec un message plus amical.
+
+en: In order to do this, we must detect that something went wrong.
+fr: Pour faire cela, nous devons détecter que quelque chose s'est mal passé.
+en: Here is one way to do this: use the type `Maybe`.
+fr: Voici un moyen de le faire : utiliser le type `Maybe`.
+en: This is a very common type in Haskell.
+fr: C'est un type très utilisé en Haskell.
+
+> import Data.Maybe
+
+en: What is this thing? `Maybe` is a type which takes one parameter.
+fr: Mais qu'est-ce que c'est ? `Maybe` est un type qui prend un paramètre.
+en: Its definition is:
+fr: Sa définition est :
+
+
+data Maybe a = Nothing | Just a
+
+
+fr: C'est un bon moyen de dire qu'il y a eu une erreur en essayant de créer/évaluer
+en: This is a nice way to tell there was an error while trying to create/compute
+fr: une valeur.
+en: a value.
+fr: La fonction `maybeRead` en est un bon exemple.
+en: The `maybeRead` function is a great example of this.
+fr: C'est une fonction similaire à `read`[^1],
+en: This is a function similar to the function `read`[^1],
+fr: mais s'il y a un problème, la valeur retournée est `Nothing`.
+en: but if something goes wrong the returned value is `Nothing`.
+fr: Si la valeur est bonne, la valeur retournée est `Just Le truc des IO révélé
+en: IO trick explained
+
+blogimage("magritte_pipe.jpg","Magritte, ceci n'est pas une pipe")
+
+fr: > Voici un %tlal pour cette section.
+en: > Here is a %tldr for this section.
+ >
+fr: > Pour séparer les parties pures et impures,
+en: > To separate pure and impure parts,
+fr: > `main` est définie comme une fonction.
+en: > `main` is defined as a function
+fr: > qui modifie l'état du monde.
+en: > which modifies the state of the world.
+ >
+ > ~~~
+ > main :: World -> World
+ > ~~~
+ >
+fr: > Une fonction aura des effets de bord si elle a ce type.
+en: > A function is guaranteed to have side effects only if it has this type.
+fr: > Mais regardez cette fonction `main` typique:
+en: > But look at a typical main function:
+ >
+ > ~~~
+ >
+ > main w0 =
+ > let (v1,w1) = action1 w0 in
+ > let (v2,w2) = action2 v1 w1 in
+ > let (v3,w3) = action3 v2 w2 in
+ > action4 v3 w3
+ > ~~~
+ >
+fr: > Nous avons beaucoup d'élements temporaires (ici, `w1`, `w2` et `w3`)
+en: > We have a lot of temporary elements (here `w1`, `w2` and `w3`)
+fr: > qui doivent être passés à l'action suivante.
+en: > which must be passed on to the next action.
+ >
+fr: > Nous créons une fonction `bind` ou `(>>=)`.
+en: > We create a function `bind` or `(>>=)`.
+fr: > Avec `bind` nous n'avons plus besoin de noms temporaires.
+en: > With `bind` we don't need temporary names anymore.
+ >
+ > ~~~
+ > main =
+ > action1 >>= action2 >>= action3 >>= action4
+ > ~~~
+ >
+fr: > Bonus: Haskell a du sucre syntaxique :
+en: > Bonus: Haskell has syntactical sugar for us:
+ >
+ > ~~~
+ > main = do
+ > v1 <- action1
+ > v2 <- action2 v1
+ > v3 <- action3 v2
+ > action4 v3
+ > ~~~
+
+
+fr: Pourquoi avons-nous utilisé cette syntaxe étrange, et quel est exactement le type `IO`?
+en: Why did we use this strange syntax, and what exactly is this `IO` type?
+fr: Cela peut sembler un peu magique.
+en: It looks a bit like magic.
+
+fr: Pour l'instant, oublions les parties pures de notre programme, et concentrons-nous
+en: For now let's just forget all about the pure parts of our program, and focus
+fr: sur les parties impures:
+en: on the impure parts:
+
+
+askUser :: IO [Integer]
+askUser = do
+ putStrLn "Enter a list of numbers (separated by commas):"
+ input <- getLine
+ let maybeList = getListFromString input in
+ case maybeList of
+ Just l -> return l
+ Nothing -> askUser
+
+main :: IO ()
+main = do
+ list <- askUser
+ print $ sum list
+
+
+fr: Première remarque : on dirait de l'impératif.
+en: First remark: this looks imperative.
+fr: Haskell est assez puissant pour faire sembler impératif du code impur.
+en: Haskell is powerful enough to make impure code look imperative.
+fr: Par exemple, si vous le vouliez vous pourriez créer une boucle `while` en Haskell.
+en: For example, if you wish you could create a `while` in Haskell.
+fr: En fait, pour utiliser les `IO`, le style impératif est en général plus approprié.
+en: In fact, for dealing with `IO`, an imperative style is generally more appropriate.
+
+fr: Mais vous devriez avoir remarqué que la notation est inhabituelle.
+en: But you should have noticed that the notation is a bit unusual.
+fr: Voici pourquoi, en détail.
+en: Here is why, in detail.
+
+fr: Dans un langage impur, l'état du monde peut être vu comme une énorme variable globale cachée.
+en: In an impure language, the state of the world can be seen as a huge hidden global variable.
+fr: Cette variable cachée est accessible par toutes les fonctions du langage.
+en: This hidden variable is accessible by all functions of your language.
+fr: Par exemple, vous pouvez lire et écrire dans un fichier avec n'importe quelle fonction.
+en: For example, you can read and write a file in any function.
+fr: Le fait que le fichier putatif existe ou non est une éventualité qui relève des états possibles que le monde courant peut prendre.
+en: Whether a file exists or not is a difference in the possible states that the world can take.
+
+fr: En Haskell l'état courant du monde n'est pas caché.
+en: In Haskell the current state of the world is not hidden.
+fr: Au contraire, il est dit _explicitement_ que `main` est une fonction qui change _potentiellement_ l'état du monde.
+en: Rather, it is _explicitly_ said that `main` is a function that _potentially_ changes the state of the world.
+fr: Son type est donc quelque chose comme :
+en: Its type is then something like:
+
+
+main :: World -> World
+
+
+fr: Les fonctions ne sont pas toutes susceptibles de modifier cette variable.
+en: Not all functions may access this variable.
+fr: Celle qui peuvent la modifier sont impures.
+en: Those which have access to this variable are impure.
+fr: Les fonctions qui ne peuvent pas agir sur la variable sont pures[^032001].
+en: Functions to which the world variable isn't provided are pure[^032001].
+
+fr: [^032001]: Il y a quelques exceptions _peu sûres_ à cette règle. Mais vous ne devriez pas en voir en application réelle, sauf pour le _debugging_.
+en: [^032001]: There are some _unsafe_ exceptions to this rule. But you shouldn't see such use in a real application except maybe for debugging purposes.
+
+fr: Haskell considère l'état du monde comme une variable à passer à `main`.
+en: Haskell considers the state of the world as an input variable to `main`.
+fr: Mais son type réel est plus proche de celui ci[^032002] :
+en: But the real type of main is closer to this one[^032002]:
+
+fr: [^032002]: Pour les curieux, le vrai type est `data IO a = IO {unIO :: State# RealWorld -> (# State# RealWorld, a #)}`. Tous les `#` ont rapport avec l'optimisation et j'ai échangé quelques champs dans mon exemple. Mais c'est l'idée de base.
+en: [^032002]: For the curious ones, the real type is `data IO a = IO {unIO :: State# RealWorld -> (# State# RealWorld, a #)}`. All the `#` has to do with optimisation and I swapped the fields in my example. But this is the basic idea.
+
+
+main :: World -> ((),World)
+
+
+fr: Le type `()` est le type "unit".
+en: The `()` type is the unit type.
+fr: Rien à voir ici.
+en: Nothing to see here.
+
+fr: Maintenant réécrivons notre fonction `main` avec cela à l'esprit :
+en: Now let's rewrite our main function with this in mind:
+
+
+main w0 =
+ let (list,w1) = askUser w0 in
+ let (x,w2) = print (sum list,w1) in
+ x
+
+
+fr: D'abord, on remarque que toutes les fonctions avec des effets de bord doivent avoir le type :
+en: First, we note that all functions which have side effects must have the type:
+
+
+World -> (a,World)
+
+
+fr: où `a` est le type du résultat.
+en: where `a` is the type of the result.
+fr: Par exemple, une fonction `getChar` aura le type `World -> (Char, World).
+en: For example, a `getChar` function should have the type `World -> (Char, World)`.
+
+fr: Une autre chose à noter est l'astuce pour corriger l'ordre d'évaluation.
+en: Another thing to note is the trick to fix the order of evaluation.
+fr: En Haskell, pour évaluer `f a b`, vous avez l'embarras du choix :
+en: In Haskell, in order to evaluate `f a b`, you have many choices:
+
+fr: - évaluer d'abord `a` puis `b` puis `f a b`
+en: - first eval `a` then `b` then `f a b`
+fr: - évaluer d'abord `b` puis `a` puis `f a b`
+en: - first eval `b` then `a` then `f a b`.
+fr: - évaluer `a` et `b` parallèlement, puis `f a b`
+en: - eval `a` and `b` in parallel then `f a b`
+
+fr: Cela vient du fait que nous avons recours à une partie pure du langage.
+en: This is true because we're working in a pure part of the language.
+
+fr: Maintenant, si vous regardez la fonction `main`, vous voyez tout de suite qu'il faut évaluer la première
+en: Now, if you look at the main function, it is clear you must eval the first
+fr: ligne avant la seconde, car pour évaluer la seconde ligne vous devez
+en: line before the second one since to evaluate the second line you have
+fr: utliser un paramètre donné suite à l'évaluation de la première ligne.
+en: to get a parameter given by the evaluation of the first line.
+
+fr: Cette astuce fonctionne très bien.
+en: This trick works like a charm.
+fr: Le compilateur donnera à chaque étape un pointeur sur l'id du nouveau monde courant.
+en: The compiler will at each step provide a pointer to a new real world id.
+fr: En réalité, `print` sera évaluée comme suit :
+en: Under the hood, `print` will evaluate as:
+
+fr: - Écrit quelque chose sur l'écran
+en: - print something on the screen
+fr: - Modifie l'id du monde
+en: - modify the id of the world
+fr: - renvoyer `((), id du nouveau monde)`.
+en: - evaluate as `((),new world id)`.
+
+fr: Maintenant, si jetez un oeil au style de la fonction `main`, vous remarquerez qu'il est clairement peu commode.
+en: Now, if you look at the style of the main function, it is clearly awkward.
+fr: Essayons de faire la même chose avec la fonction `askUser` :
+en: Let's try to do the same to the `askUser` function:
+
+
+askUser :: World -> ([Integer],World)
+
+
+fr: Avant :
+en: Before:
+
+
+askUser :: IO [Integer]
+askUser = do
+ putStrLn "Enter a list of numbers:"
+ input <- getLine
+ let maybeList = getListFromString input in
+ case maybeList of
+ Just l -> return l
+ Nothing -> askUser
+
+
+fr: Après :
+en: After:
+
+
+askUser w0 =
+ let (_,w1) = putStrLn "Enter a list of numbers:" in
+ let (input,w2) = getLine w1 in
+ let (l,w3) = case getListFromString input of
+ Just l -> (l,w2)
+ Nothing -> askUser w2
+ in
+ (l,w3)
+
+
+fr: C'est similaire, mais peu commode.
+en: This is similar, but awkward.
+fr: Voyez-vous toutes ces variables temporaires `w?`.
+en: Look at all these temporary `w?` names.
+
+fr: Voici la leçon : une implémentation naïve des IO dans les langages fonctionnels purs serait maladroite !
+en: The lesson is: naive IO implementation in Pure functional languages is awkward!
+
+fr: Heureusement, il y a un meilleur moyen de résoudre ce problème.
+en: Fortunately, there is a better way to handle this problem.
+fr: Nous voyons un motif.
+en: We see a pattern.
+fr: Chaque ligne est de la forme :
+en: Each line is of the form:
+
+
+let (y,w') = action x w in
+
+
+fr: Même si pour certaines lignes l'argument `x` n'est pas nécessaire.
+en: Even if for some lines the first `x` argument isn't needed.
+fr: La sortie est un couple, `(answer, newWorldValue)`.
+en: The output type is a couple, `(answer, newWorldValue)`.
+fr: Chaque fonction `f` doit avoir un type similaire à :
+en: Each function `f` must have a type similar to:
+
+
+f :: World -> (a,World)
+
+
+fr: Et ce n'est pas fini, nous pouvons aussi remarquer que nous suivons toujours le même motif :
+en: Not only this, but we can also note that we always follow the same usage pattern:
+
+
+let (y,w1) = action1 w0 in
+let (z,w2) = action2 w1 in
+let (t,w3) = action3 w2 in
+...
+
+
+fr: Chaque action peut prendre de 0 à n paramètres.
+en: Each action can take from 0 to n parameters.
+fr: Et en particulier, chaque action prend comme paramètre le résultat de la ligne précédente.
+en: And in particular, each action can take a parameter from the result of a line above.
+
+fr: Par exemple, nous pourrions aussi avoir :
+en: For example, we could also have:
+
+
+let (_,w1) = action1 x w0 in
+let (z,w2) = action2 w1 in
+let (_,w3) = action3 z w2 in
+...
+
+
+fr: Avec, bien entendu, `actionN w :: (World) -> (a,World)`.
+en: With, of course: `actionN w :: (World) -> (a,World)`.
+
+fr: > IMPORTANT: Il y a seulement 2 schémas importants à considérer :
+en: > IMPORTANT: there are only two important patterns to consider:
+ >
+ > ~~~
+ > let (x,w1) = action1 w0 in
+ > let (y,w2) = action2 x w1 in
+ > ~~~
+ >
+fr: > et
+en: > and
+ >
+ > ~~~
+ > let (_,w1) = action1 w0 in
+ > let (y,w2) = action2 w1 in
+ > ~~~
+
+leftblogimage("jocker_pencil_trick.jpg","Jocker pencil trick")
+
+fr: Maintenant, préparez-vous pour un petit tour de magie !
+en: Now, we will do a magic trick.
+fr: Faisons disparaître les variables temporaires de monde courant.
+en: We will make the temporary world symbols "disappear".
+fr: Nous allons `attacher` (_NDT: `bind` en anglais_) les deux lignes.
+en: We will `bind` the two lines.
+fr: Définissons la fonction `bind`.
+en: Let's define the `bind` function.
+fr: Son type est assez intimidant au début :
+en: Its type is quite intimidating at first:
+
+
+bind :: (World -> (a,World))
+ -> (a -> (World -> (b,World)))
+ -> (World -> (b,World))
+
+
+fr: Mais gardez en tête que `(World -> (a,World))` est le type d'une action d'IO.
+en: But remember that `(World -> (a,World))` is the type for an IO action.
+fr: Renommons-le pour plus de clarté :
+en: Now let's rename it for clarity:
+
+
+type IO a = World -> (a, World)
+
+
+fr: Quelques exemples de fonctions :
+en: Some examples of functions:
+
+
+getLine :: IO String
+print :: Show a => a -> IO ()
+
+
+fr: `getLine` est une action d'E/S qui prend le monde en paramètre et retourne un couple `(String, World)`.
+en: `getLine` is an IO action which takes world as a parameter and returns a couple `(String, World)`.
+fr: Cela peut être résumé par : `getLine` est de type `IO String`, que nous pouvons voir comme une action d'E/S qui retournera une chaîne de caractères "dans une E/S".
+en: This can be summarized as: `getLine` is of type `IO String`, which we also see as an IO action which will return a String "embeded inside an IO".
+
+fr: La fonction `print` est elle aussi intéressante.
+en: The function `print` is also interesting.
+fr: Elle prend un argument qui peut être montré avec `show`.
+en: It takes one argument which can be shown.
+fr: En fait, elle prend deux arguments.
+en: In fact it takes two arguments.
+fr: Le premier est la valeur et le deuxième est l'état du monde.
+en: The first is the value to print and the other is the state of world.
+fr: Elle retourne un couple de type `((), World)`.
+en: It then returns a couple of type `((), World)`.
+fr: Cela signifie qu'elle change l'état du monde, mais ne produit pas d'autre donnée.
+en: This means that it changes the state of the world, but doesn't yield any more data.
+
+fr: Ce nouveau type `IO a` nous aide à simplifier le type de `bind` :
+en: This new `IO a` type helps us simplify the type of `bind`:
+
+
+bind :: IO a
+ -> (a -> IO b)
+ -> IO b
+
+
+fr: Cela dit que `bind` prend deux actions d'E/S en paramètres et retourne une autre action d'E/S.
+en: It says that `bind` takes two IO actions as parameters and returns another IO action.
+
+fr: Maintenant, rappelez-vous des motifs _importants_. Le premier était :
+en: Now, remember the _important_ patterns. The first was:
+
+
+pattern1 w0 =
+ let (x,w1) = action1 w0 in
+ let (y,w2) = action2 x w1 in
+ (y,w2)
+
+
+fr: Voyez les types :
+en: Look at the types:
+
+
+action1 :: IO a
+action2 :: a -> IO b
+pattern1 :: IO b
+
+
+fr: Cela ne vous semble-t-il pas familier ?
+en: Doesn't it seem familiar?
+
+
+(bind action1 action2) w0 =
+ let (x, w1) = action1 w0
+ (y, w2) = action2 x w1
+ in (y, w2)
+
+
+fr: L'idée est de cacher l'argument `World` avec cette fonction. Allons-y !
+en: The idea is to hide the World argument with this function. Let's go:
+fr: Par exemple si nous avions voulu simuler :
+en: As an example imagine if we wanted to simulate:
+
+
+let (line1, w1) = getLine w0 in
+let ((), w2) = print line1 in
+((), w2)
+
+
+fr: Maintenant, en utilisant la fonction `bind` :
+en: Now, using the `bind` function:
+
+
+(res, w2) = (bind getLine print) w0
+
+
+fr: Comme `print` est de type `Show a => a -> (World -> ((), World))`, nous savons que `res = ()` (type `unit`)
+en: As print is of type `Show a => a -> (World -> ((), World))`, we know `res = ()` (`unit` type).
+fr: Si vous ne voyez pas ce qui est magique ici, essayons avec trois lignes cette fois.
+en: If you didn't see what was magic here, let's try with three lines this time.
+
+
+
+let (line1,w1) = getLine w0 in
+let (line2,w2) = getLine w1 in
+let ((),w3) = print (line1 ++ line2) in
+((),w3)
+
+
+fr: Qui est équivalent à :
+en: Which is equivalent to:
+
+
+(res,w3) = (bind getLine (\line1 ->
+ (bind getLine (\line2 ->
+ print (line1 ++ line2))))) w0
+
+
+fr: Avez-vous remarqué quelque chose ?
+en: Didn't you notice something?
+fr: Oui, aucune variable `World` temporaire n'est utilisée !
+en: Yes, no temporary World variables are used anywhere!
+fr: C'est _MA_._GIQUE_.
+en: This is _MA_. _GIC_.
+
+fr: Nous pouvons utiliser une meilleure notation.
+en: We can use a better notation.
+fr: Utilisons `(>>=)` au lieu de `bind`.
+en: Let's use `(>>=)` instead of `bind`.
+fr: `(>>=)` est une fonction infixe, comme
+en: `(>>=)` is an infix function like
+fr: `(+)`; pour mémoire : `3 + 4 ⇔ (+) 3 4`
+en: `(+)`; reminder `3 + 4 ⇔ (+) 3 4`
+
+
+(res,w3) = (getLine >>=
+ (\line1 -> getLine >>=
+ (\line2 -> print (line1 ++ line2)))) w0
+
+
+fr: Ho Ho Ho! Joyeux Noël !
+fr; Haskell a confectionné du sucre syntaxique pour vous :
+en: Ho Ho Ho! Merry Christmas Everyone!
+en: Haskell has made syntactical sugar for us:
+
+
+do
+ x <- action1
+ y <- action2
+ z <- action3
+ ...
+
+
+fr: Est remplacé par :
+en: Is replaced by:
+
+
+action1 >>= (\x ->
+action2 >>= (\y ->
+action3 >>= (\z ->
+...
+)))
+
+
+fr: Remarquez que vous pouvez utliser `x` dans `action2` et `x` et `y` dans `action3`.
+en: Note that you can use `x` in `action2` and `x` and `y` in `action3`.
+
+fr: Mais que se passe-t-il pour les lignes qui n'utilisent pas le `<-` ?
+en: But what about the lines not using the `<-`?
+fr: Facile, une autre fonction `blindBind` :
+en: Easy, another function `blindBind`:
+
+
+blindBind :: IO a -> IO b -> IO b
+blindBind action1 action2 w0 =
+ bind action (\_ -> action2) w0
+
+
+fr: Je n'ai pas simplifié cette définition pour plus de clarté.
+en: I didn't simplify this definition for the purposes of clarity.
+fr: Bien sûr, nous pouvons utiliser une meilleure notation avec l'opérateur `(>>)`.
+en: Of course, we can use a better notation: we'll use the `(>>)` operator.
+
+fr: Et
+en: And
+
+
+do
+ action1
+ action2
+ action3
+
+
+fr: Devient
+en: Is transformed into
+
+
+action1 >>
+action2 >>
+action3
+
+
+fr: Enfin, une autre fonction est plutôt utile.
+en: Also, another function is quite useful.
+
+
+putInIO :: a -> IO a
+putInIO x = IO (\w -> (x,w))
+
+
+fr: D'une manière générale, c'est une façon de mettre des valeurs pures dans le "contexte d'E/S".
+en: This is the general way to put pure values inside the "IO context".
+fr: Le nom général pour `putInIO` est `return`.
+en: The general name for `putInIO` is `return`.
+fr: C'est un plutôt un mauvais nom lorsque vous commencez à programmer en Haskell. `return` est très différent de ce à quoi vous pourriez être habitué.
+en: This is quite a bad name when you learn Haskell. `return` is very different from what you might be used to.
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/01_IO/21_Detailled_IO.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/01_IO/21_Detailled_IO.lhs
new file mode 100644
index 0000000..f0c9dee
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/01_IO/21_Detailled_IO.lhs
@@ -0,0 +1,49 @@
+fr: Pour finir, traduisons notre exemple :
+en: To finish, let's translate our example:
+
+
+
+askUser :: IO [Integer]
+askUser = do
+ putStrLn "Enter a list of numbers (separated by commas):"
+ input <- getLine
+ let maybeList = getListFromString input in
+ case maybeList of
+ Just l -> return l
+ Nothing -> askUser
+
+main :: IO ()
+main = do
+ list <- askUser
+ print $ sum list
+
+
+fr: Se traduit en :
+en: Is translated into:
+
+> import Data.Maybe
+>
+> maybeRead :: Read a => String -> Maybe a
+> maybeRead s = case reads s of
+> [(x,"")] -> Just x
+> _ -> Nothing
+> getListFromString :: String -> Maybe [Integer]
+> getListFromString str = maybeRead $ "[" ++ str ++ "]"
+> askUser :: IO [Integer]
+> askUser =
+> putStrLn "Enter a list of numbers (sep. by commas):" >>
+> getLine >>= \input ->
+> let maybeList = getListFromString input in
+> case maybeList of
+> Just l -> return l
+> Nothing -> askUser
+>
+> main :: IO ()
+> main = askUser >>=
+> \list -> print $ sum list
+
+fr: Vous pouvez compiler ce code pour vérifier qu'il marche.
+en: You can compile this code to verify that it works.
+
+fr: Imaginez à quoi il ressemblerait sans le `(>>)` et `(>>=)`.
+en: Imagine what it would look like without the `(>>)` and `(>>=)`.
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/02_Monads/10_Monads.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/02_Monads/10_Monads.lhs
new file mode 100644
index 0000000..b658ee8
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/02_Monads/10_Monads.lhs
@@ -0,0 +1,124 @@
+fr: Les monades
+en: Monads
+
+blogimage("dali_reve.jpg","Dali, reve. It represents a weapon out of the mouth of a tiger, itself out of the mouth of another tiger, itself out of the mouth of a fish itself out of a grenade. I could have choosen a picture of the Human centipede as it is a very good representation of what a monad really is. But just to think about it, I find this disgusting and that wasn't the purpose of this document.")
+
+fr: Maintenant le secret peut être dévoilé : `IO` est une _monade_.
+en: Now the secret can be revealed: `IO` is a _monad_.
+fr: Être une monade signifie que vous avez accès à du sucre syntaxique avec la notation `do`.
+en: Being a monad means you have access to some syntactical sugar with the `do` notation.
+fr: Mais principalement, vous avez accès à un motif de codage qui tempérera le flux de votre code.
+en: But mainly, you have access to a coding pattern which will ease the flow of your code.
+
+fr: > **Remarques importantes** :
+en: > **Important remarks**:
+ >
+fr: > - Le monades n'ont pas forcément quoi que ce soit à voir avec les effets de bord !
+en: > - Monad are not necessarily about effects!
+fr: > Il y a beaucoup de monades _pures_.
+en: > There are a lot of _pure_ monads.
+fr: > - Les monades concernent plus le séquençage.
+en: > - Monad are more about sequencing
+
+fr: En Haskell, `Monad` est une classe de type.
+en: In Haskell, `Monad` is a type class.
+fr: Pour être une instance d'une classe de type, vous devez fournir les fonctions `(>>=)` et `return`.
+en: To be an instance of this type class, you must provide the functions `(>>=)` and `return`.
+fr: La fonction `(>>)` est dérivée de `(>>=)`.
+en: The function `(>>)` is derived from `(>>=)`.
+fr: Voici commment la classe de type `Monad` est déclarée (grosso modo) :
+en: Here is how the type class `Monad` is declared (basically):
+
+
+class Monad m where
+ (>>=) :: m a -> (a -> m b) -> m b
+ return :: a -> m a
+
+ (>>) :: m a -> m b -> m b
+ f >> g = f >>= \_ -> g
+
+fr: -- Vous pouvez ignorer cette fonction généralement,
+en: -- You should generally safely ignore this function
+fr: -- je crois qu'elle existe pour des raisons historiques
+en: -- which I believe exists for historical reasons
+ fail :: String -> m a
+ fail = error
+
+
+
+fr: > Remarques :
+en: > Remarks:
+ >
+fr: > - le mot-clé `class` n'est pas votre ami.
+en: > - the keyword `class` is not your friend.
+fr: > Une classe en Haskell _n'est pas_ du même genre que celle des langages orientés-objet.
+en: > A Haskell class is _not_ a class of the kind you will find in object-oriented programming.
+fr: > Elles ont beaucoup de similarités avec les interfaces de Java.
+en: > A Haskell class has a lot of similarities with Java interfaces.
+fr: > Un meilleur mot aurait été `typeClass`, ce qui signifierait un ensemble de types.
+en: > A better word would have been `typeclass`, since that means a set of types.
+fr: > Pour qu'un type appartienne à une classe, toutes les fonctions de cette classe doivent être fournies pour ce type.
+en: > For a type to belong to a class, all functions of the class must be provided for this type.
+fr: > - Dans cet exemple particulier de classe de type, le type `m` doit être un type qui prend un argument.
+en: > - In this particular example of type class, the type `m` must be a type that takes an argument.
+fr: > par exemple `IO a`, mais aussi `Maybe a`, `[a]`, etc...
+en: > for example `IO a`, but also `Maybe a`, `[a]`, etc...
+fr: > - Pour être une monade utile, votre fonction doit obéir à quelques règles.
+en: > - To be a useful monad, your function must obey some rules.
+fr: > Si votre construction n'obéit pas à ces règles, des choses étranges pourraient se produire :
+en: > If your construction does not obey these rules strange things might happens:
+
+ > ~~~
+ > return a >>= k == k a
+ > m >>= return == m
+ > m >>= (\x -> k x >>= h) == (m >>= k) >>= h
+ > ~~~
+
+fr: Maybe est une monade
+en: Maybe is a monad
+
+fr: Il y a beaucoup de types différents qui sont des instances de `Monad`.
+en: There are a lot of different types that are instances of `Monad`.
+fr: L'un des plus faciles à décrire est `Maybe`.
+en: One of the easiest to describe is `Maybe`.
+fr: Si vous avez une séquence de valeurs `Maybe`, vous pouvez utiliser les monades pour les manipuler.
+en: If you have a sequence of `Maybe` values, you can use monads to manipulate them.
+fr: C'est particulièrement utile pour enlever des constructions `if..then..else..` trop nombreuses.
+en: It is particularly useful to remove very deep `if..then..else..` constructions.
+
+fr: Imaginez une opération bancaire complexe. Vous êtes éligible pour gagner 700€ seulement si
+en: Imagine a complex bank operation. You are eligible to gain about 700€ only
+fr: vous pouvez effectuer une liste d'opérations sans tomber en dessous de zéro.
+en: if you can afford to follow a list of operations without your balance dipping below zero.
+
+> deposit value account = account + value
+> withdraw value account = account - value
+>
+> eligible :: (Num a,Ord a) => a -> Bool
+> eligible account =
+> let account1 = deposit 100 account in
+> if (account1 < 0)
+> then False
+> else
+> let account2 = withdraw 200 account1 in
+> if (account2 < 0)
+> then False
+> else
+> let account3 = deposit 100 account2 in
+> if (account3 < 0)
+> then False
+> else
+> let account4 = withdraw 300 account3 in
+> if (account4 < 0)
+> then False
+> else
+> let account5 = deposit 1000 account4 in
+> if (account5 < 0)
+> then False
+> else
+> True
+>
+> main = do
+> print $ eligible 300 -- True
+> print $ eligible 299 -- False
+
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/02_Monads/11_Monads.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/02_Monads/11_Monads.lhs
new file mode 100644
index 0000000..40efd31
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/02_Monads/11_Monads.lhs
@@ -0,0 +1,23 @@
+fr: Maintenant, améliorons cela en utilisant le fait que `Maybe` est une Monade.
+en: Now, let's make it better using Maybe and the fact that it is a Monad
+
+> deposit :: (Num a) => a -> a -> Maybe a
+> deposit value account = Just (account + value)
+>
+> withdraw :: (Num a,Ord a) => a -> a -> Maybe a
+> withdraw value account = if (account < value)
+> then Nothing
+> else Just (account - value)
+>
+> eligible :: (Num a, Ord a) => a -> Maybe Bool
+> eligible account = do
+> account1 <- deposit 100 account
+> account2 <- withdraw 200 account1
+> account3 <- deposit 100 account2
+> account4 <- withdraw 300 account3
+> account5 <- deposit 1000 account4
+> Just True
+>
+> main = do
+> print $ eligible 300 -- Just True
+> print $ eligible 299 -- Nothing
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/02_Monads/12_Monads.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/02_Monads/12_Monads.lhs
new file mode 100644
index 0000000..f0871c5
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/02_Monads/12_Monads.lhs
@@ -0,0 +1,66 @@
+fr: Pas mauvais, mais nous pouvons faire encore mieux :
+en: Not bad, but we can make it even better:
+
+> deposit :: (Num a) => a -> a -> Maybe a
+> deposit value account = Just (account + value)
+>
+> withdraw :: (Num a,Ord a) => a -> a -> Maybe a
+> withdraw value account = if (account < value)
+> then Nothing
+> else Just (account - value)
+>
+> eligible :: (Num a, Ord a) => a -> Maybe Bool
+> eligible account =
+> deposit 100 account >>=
+> withdraw 200 >>=
+> deposit 100 >>=
+> withdraw 300 >>=
+> deposit 1000 >>
+> return True
+>
+> main = do
+> print $ eligible 300 -- Just True
+> print $ eligible 299 -- Nothing
+
+fr: Nous avons prouvé que les monades sont un bon moyen de rendre notre code plus élégant.
+en: We have proven that Monads are a good way to make our code more elegant.
+fr: Remarquez que cette idée d'organisation de code, en particulier pour `Maybe`, peut être utilisée
+en: Note this idea of code organization, in particular for `Maybe` can be used
+fr: dans la plupart des langages impératifs.
+en: in most imperative languages.
+fr: En fait, c'est le type de construction que nous faisons naturellement.
+en: In fact, this is the kind of construction we make naturally.
+
+fr: > Une remarque importante :
+en: > An important remark:
+ >
+fr: > Le premier élement de la séquence qui sera évalué comme `Nothing` stoppera
+en: > The first element in the sequence being evaluated to `Nothing` will stop
+fr: > l'évaluation.
+en: > the complete evaluation.
+fr: > Cela signifie que vous n'exécutez pas toutes les lignes.
+en: > This means you don't execute all lines.
+fr: > Cela découle du caractère paresseux de Haskell.
+en: > You get this for free, thanks to laziness.
+
+fr: Vous pourriez aussi revoir ces exemples avec la définition de `(>>=)` pour `Maybe`
+en: You could also replay these example with the definition of `(>>=)` for `Maybe`
+fr: en tête :
+en: in mind:
+
+
+instance Monad Maybe where
+ (>>=) :: Maybe a -> (a -> Maybe b) -> Maybe b
+ Nothing >>= _ = Nothing
+ (Just x) >>= f = f x
+
+ return x = Just x
+
+
+
+fr: La monade `Maybe` a prouvé par un simple exemple qu'elle est utile.
+en: The `Maybe` monad proved to be useful while being a very simple example.
+fr: Nous avons vu l'utilité de la monade `IO`.
+en: We saw the utility of the `IO` monad.
+fr: Mais maintenant, voici un exemple encore plus cool : les listes.
+en: But now for a cooler example, lists.
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/02_Monads/13_Monads.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/02_Monads/13_Monads.lhs
new file mode 100644
index 0000000..e32e638
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/03_Hell/02_Monads/13_Monads.lhs
@@ -0,0 +1,67 @@
+fr: La monade List
+en: The list monad
+
+blogimage("golconde.jpg","Golconde de Magritte")
+
+fr: La monade `List` nous aide à simuler des calculs non-déterministes.
+en: The list monad helps us to simulate non-deterministic computations.
+fr: C'est parti :
+en: Here we go:
+
+> import Control.Monad (guard)
+>
+> allCases = [1..10]
+>
+> resolve :: [(Int,Int,Int)]
+> resolve = do
+> x <- allCases
+> y <- allCases
+> z <- allCases
+> guard $ 4*x + 2*y < z
+> return (x,y,z)
+>
+> main = do
+> print resolve
+
+
+fr: Ma. GIQUE. :
+en: MA. GIC. :
+
+~~~
+[(1,1,7),(1,1,8),(1,1,9),(1,1,10),(1,2,9),(1,2,10)]
+~~~
+
+fr: Pour la monade `List`, il y a aussi un sucre syntaxique :
+en: For the list monad, there is also this syntactic sugar:
+
+> print $ [ (x,y,z) | x <- allCases,
+> y <- allCases,
+> z <- allCases,
+> 4*x + 2*y < z ]
+
+fr: Je ne listerai pas toutes les monades, car il y en a beaucoup.
+en: I won't list all the monads, since there are many of them.
+fr: Utiliser les monades simplifie la manipulations de plusieurs notions dans les langages purs.
+en: Using monads simplifies the manipulation of several notions in pure languages.
+fr: Les monades sont très utiles, en particulier pour :
+en: In particular, monads are very useful for:
+
+fr: - L'E/S (IO),
+en: - IO,
+fr: - les calculs non-déterministes,
+en: - non-deterministic computation,
+fr: - générer des nombres pseudo-aléatoires,
+en: - generating pseudo random numbers,
+fr: - garder un état de configuration,
+en: - keeping configuration state,
+fr: - écrire un état,
+en: - writing state,
+- ...
+
+fr: Si vous m'avez suivi jusqu'ici, alors vous avez terminé !
+en: If you have followed me until here, then you've done it!
+fr: Vous connaissez les monades[^03021301] !
+en: You know monads[^03021301]!
+
+fr: [^03021301]: Vous aurez quand même besoin de pratiquer un peu pour vous habituer à elles et pour comprendre quand les utiliser et créer les vôtres. Mais vous avez déjà fait un grand pas dans cette direction.
+en: [^03021301]: Well, you'll certainly need to practice a bit to get used to them and to understand when you can use them and create your own. But you already made a big step in this direction.
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/04_Appendice/00_appendix.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/04_Appendice/00_appendix.lhs
new file mode 100644
index 0000000..61f2030
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/04_Appendice/00_appendix.lhs
@@ -0,0 +1,7 @@
+fr: Appendice
+en: Appendix
+
+fr: Cette section n'est pas vraiment sur l'apprentissage d'Haskell.
+en: This section is not so much about learning Haskell.
+fr: Elle est ici pour discuter de quelques détails.
+en: It is just here to discuss some details further.
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/04_Appendice/01_More_on_infinite_trees/10_Infinite_Trees.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/04_Appendice/01_More_on_infinite_trees/10_Infinite_Trees.lhs
new file mode 100644
index 0000000..7d1f01f
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/04_Appendice/01_More_on_infinite_trees/10_Infinite_Trees.lhs
@@ -0,0 +1,160 @@
+fr: Revenons sur les arbres infinis
+en: More on Infinite Tree
+
+fr: Dans la section sur [les structures infinies](#infinite-structures) nous avons vu quelques
+en: In the section [Infinite Structures](#infinite-structures) we saw some simple
+fr: constructions simples.
+en: constructions.
+fr: Malheureusement, nous avons enlevé deux propriétés de notre arbre:
+en: Unfortunately we removed two properties from our tree:
+
+fr: 1. Pas de valeurs identiques
+en: 1. no duplicate node value
+fr: 2. Arbre bien ordonné
+en: 2. well ordered tree
+
+fr: Dans cette section nous allons tenter de garder la première propriété.
+en: In this section we will try to keep the first property.
+fr: Concernant la seconde, nous ne devons pas nous en préoccuper ici mais nous discuterons
+en: Concerning the second one, we must relax it but we'll discuss how to
+fr: de comment la garder le plus possible.
+en: keep it as much as possible.
+
+
+
+fr: Notre première étape est de créer une liste de nombres pseudo-aléatoires:
+en: Our first step is to create some pseudo-random number list:
+
+> shuffle = map (\x -> (x*3123) `mod` 4331) [1..]
+
+fr: Pour mémoire, voici la définition de `treeFromList`
+en: Just as a reminder, here is the definition of `treeFromList`
+
+> treeFromList :: (Ord a) => [a] -> BinTree a
+> treeFromList [] = Empty
+> treeFromList (x:xs) = Node x (treeFromList (filter (
+treeTakeDepth 4 (treeFromList [1..])
+
+
+fr: tournera en boucle pour toujours.
+en: will loop forever.
+fr: Simplement parce que le code essayera d'accéder à première valeur de `filter (<1) [2..]`.
+en: Simply because it will try to access the head of `filter (<1) [2..]`.
+fr: Mais `filter` n'est pas assez intelligent pour comprendre que le résultat est une liste vide.
+en: But `filter` is not smart enought to understand that the result is the empty list.
+
+fr: Toutefois, cela reste un exemple sympa de ce qu'un programme non-stricit a à offrir.
+en: Nonetheless, it is still a very cool example of what non strict programs have to offer.
+
+fr: Laissé pour exercice au lecteur:
+en: Left as an exercise to the reader:
+
+fr: - Prouver l'existence d'un nombre `n` tel que `treeTakeDepth n (treeFromList shuffle)` provoquera une boucle infinie.
+en: - Prove the existence of a number `n` so that `treeTakeDepth n (treeFromList shuffle)` will enter an infinite loop.
+fr: - Trouver une borne supérieur `n`.
+en: - Find an upper bound for `n`.
+fr: - Prouver qu'il n(y a pas de liste `shuffle` qui termine le programme pour n'importe quelle profondeur.
+en: - Prove there is no `shuffle` list so that, for any depth, the program ends.
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/04_Appendice/01_More_on_infinite_trees/11_Infinite_Trees.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/04_Appendice/01_More_on_infinite_trees/11_Infinite_Trees.lhs
new file mode 100644
index 0000000..13e2b44
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/04_Appendice/01_More_on_infinite_trees/11_Infinite_Trees.lhs
@@ -0,0 +1,192 @@
+
+
+
+fr: Pour résoudre ces problèmes nous allons modifier légèrement nos
+en: In order to resolve these problem we will modify slightly our
+fr: fonctions `treeFromList` et `shuffle`.
+en: `treeFromList` and `shuffle` function.
+
+fr: Un premier problème est le manque de nombres différents dans notre immlémentation de `shuffle`.
+en: A first problem, is the lack of infinite different number in our implementation of `shuffle`.
+fr: Nous avons généré seulement `4331` nombres différents.
+en: We generated only `4331` different numbers.
+fr: Pour résoudre cela nous allons faire un meilleure fonction `shuffle`.
+en: To resolve this we make a slightly better `shuffle` function.
+
+> shuffle = map rand [1..]
+> where
+> rand x = ((p x) `mod` (x+c)) - ((x+c) `div` 2)
+> p x = m*x^2 + n*x + o -- some polynome
+> m = 3123
+> n = 31
+> o = 7641
+> c = 1237
+
+fr: Cette fonction à la propriété de ne pas avoir de bornes supérieure ou inférieure.
+en: This shuffle function has the property (hopefully) not to have an upper nor lower bound.
+fr: Mais avoir une meilleure list `shuffle` n'est pas assez pour entrer dans une boucle infinie.
+en: But having a better shuffle list isn't enough not to enter an infinite loop.
+
+fr: Généralement, nous ne pouvons pas décider que `filter (
+ safefilter' f l = if filter f (take 10000 l) == []
+ then []
+ else filter f l
+
+fr: Expliquer pourquoi cela ne fonctionne pas et peut entrer dans une boucle infinie.
+en: Explain why it doesn't work and can enter into an infinite loop.
+fr: - Supposez que `shuffle` est une liste de nombre réellement aléatoires avec de plus en plus de bornes.
+en: - Suppose that `shuffle` is real random list with growing bounds.
+fr: Si vous étudiez un peu cette structure, vous découvrirez qu'elle a toutes les chances
+en: If you study a bit this structure, you'll discover that with probability 1,
+fr: d'être finie.
+en: this structure is finite.
+fr: En utilisant le code suivant
+en: Using the following code
+fr: (supposez que nous pouvons utliser `safefilter'` directement comme si cela n'était pas dans le `where` de `safefilter`.
+en: (suppose we could use `safefilter'` directly as if was not in the where of safefilter)
+fr: trouvez une définition de `f` telle que, avec une probabilité de `1`,
+en: find a definition of `f` such that with probability `1`,
+fr: `treeFromList' shuffle` est infinie?. Et prouvez-le.
+en: `treeFromList' shuffle` is infinite. And prove it.
+fr: Avertissement, ce n'est qu'une conjecture.
+en: Disclaimer, this is only a conjecture.
+
+
+treeFromList' [] n = Empty
+treeFromList' (x:xs) n = Node x left right
+ where
+ left = treeFromList' (safefilter' (
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/code/04_Appendice/02_Thanks/10_Thanks.lhs b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/04_Appendice/02_Thanks/10_Thanks.lhs
new file mode 100644
index 0000000..7e11e0c
--- /dev/null
+++ b/src/Scratch/en/blog/Haskell-the-Hard-Way/code/04_Appendice/02_Thanks/10_Thanks.lhs
@@ -0,0 +1,15 @@
+en: ## Thanks
+fr: ## Remerciements
+
+fr: Merci à [`/r/haskell`](http://reddit.com/r/haskell) et
+en: Thanks to [`/r/haskell`](http://reddit.com/r/haskell) and
+[`/r/programming`](http://reddit.com/r/programming).
+fr: Vos commentaires étaient plus que bienvenus.
+en: Your comment were most than welcome.
+
+fr: Particulièrement, je voudrais remercier mille fois [Emm](https://github.com/Emm)
+en: Particularly, I want to thank [Emm](https://github.com/Emm) a thousand times
+fr: pour le temps qu'il a consacré à corriger mon anglais.
+en: for the time he spent on correcting my English.
+fr: Merci beaucoup.
+en: Thank you man.
diff --git a/src/Scratch/en/blog/Haskell-the-Hard-Way/index.html b/src/Scratch/en/blog/Haskell-the-Hard-Way/index.html
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+
+
+
+
diff --git a/src/Scratch/en/blog/Helping-avoid-Haskell-Success/index.html b/src/Scratch/en/blog/Helping-avoid-Haskell-Success/index.html
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+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Learn Haskell Fast and Hard
+ Blow your mind with Haskell
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Table of Content
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Note: Each time you see a separator with a filename ending in
+.lhs you can click the filename to get this file. If you save the file as filename.lhs, you can run it with
+
+runhaskell filename.lhs
+
+
+
+Introduction
+
+
+Install
+
+
+
+
+stack.
+
+ghc: Compiler similar to gcc for C.ghci: Interactive Haskell (REPL)runhaskell: Execute a program without compiling it. Convenient but very slow compared to compiled programs.
+Don’t be afraid
+
+
+
+
+hello.hs and:stack first run stack setup and then:00_hello_world.lhs and:
+
+// In C
+#include <stdio.h>
+int main (int argc, char **argv) {
+ char name[666]; // <- An Evil Number!
+ // What if my name is more than 665 character long?
+ printf("What is your name?\n");
+ scanf("%s", name);
+ printf("Hello %s!\n", name);
+ return 0;
+}main function and every object has a type. The type of main is IO (). This means main will cause side effects.
+
+Very basic Haskell
+
+
+
+
+C, C++ or Java, the type system is here to help you.
+
+>>=, <$>, <- or any other weird symbol, just ignore them and follows the flow of the code.
+Function declaration
+
+C:def.
+A Type Example
+
+::
+~ runhaskell 20_very_basic.lhs
+13
+
+21_very_basic.lhs:6:23:
+ No instance for (Fractional Int)
+ arising from the literal `4.2'
+ Possible fix: add an instance declaration for (Fractional Int)
+ In the second argument of `f', namely `4.2'
+ In the first argument of `print', namely `(f 2.3 4.2)'
+ In the expression: print (f 2.3 4.2)4.2 isn’t an Int.
+f for the moment and let Haskell infer the most general type for us:C, you’ll have to declare a function for int, for float, for long, for double, etc…
+% ghci
+
+GHCi, version 7.0.4: http://www.haskell.org/ghc/ :? for help
+Loading package ghc-prim ... linking ... done.
+Loading package integer-gmp ... linking ... done.
+Loading package base ... linking ... done.
+Loading package ffi-1.0 ... linking ... done.
+Prelude> let f x y = x*x + y*y
+Prelude> :type f
+f :: Num a => a -> a -> a
+
+Num a => a -> a -> aa -> a -> a. To understand it, just look at a list of progressive examples:
+
+
+
+
+
+The written type
+Its meaning
+
+
+Intthe type
+Int
+
+Int -> Intthe type function from
+Int to Int
+
+Float -> Intthe type function from
+Float to Int
+
+a -> Intthe type function from any type to
+Int
+
+a -> athe type function from any type
+a to the same type a
+
+
+a -> a -> athe type function of two arguments of any type
+a to the same type aa -> a -> a, the letter a is a type variable. It means f is a function with two arguments and both arguments and the result have the same type. The type variable a could take many different type values. For example Int, Integer, Float…C and having to declare a function for int, long, float, double, etc., we declare only one function like in a dynamically typed language.a can be any type, for example a String or an Int, but also more complex types, like Trees, other functions, etc. But here our type is prefixed with Num a =>.Num is a type class. A type class can be understood as a set of types. Num contains only types which behave like numbers. More precisely, Num is class containing types which implement a specific list of functions, and in particular (+) and (*).Num a => a -> a -> a means:a be a type belonging to the Num type class. This is a function from type a to (a -> a).f 3 4 is equivalent to (f 3) 4. Note f 3 is a function:
+f :: Num a => a -> a -> a
+
+g :: Num a => a -> a
+g = f 3
+
+g y ⇔ 3*3 + y*y
+g = \y -> 3*3 + y*y\ is used because it looks like λ and is ASCII.
+3 is a valid representation both for Fractional numbers like Float and for Integer. As 2.4 is a Fractional number, 3 is then interpreted as being also a Fractional number.
+
+
+
+
+Essential Haskell
+
+
+
+
+⇔ symbol to state that two expression are equivalent. It is a meta notation, ⇔ does not exists in Haskell. I will also use ⇒ to show what the return value of an expression is.
+Notations
+
+
+Arithmetic
+
+
+3 + 2 * 6 / 3 ⇔ 3 + ((2*6)/3)
+Logic
+
+
+True || False ⇒ True
+True && False ⇒ False
+True == False ⇒ False
+True /= False ⇒ True (/=) is the operator for different
+Powers
+
+
+x^n for n an integral (understand Int or Integer)
+x**y for y any kind of number (Float for example)Integer has no limit except the capacity of your machine:
+4^103
+102844034832575377634685573909834406561420991602098741459288064Data.Ratio:
+$ ghci
+....
+Prelude> :m Data.Ratio
+Data.Ratio> (11 % 15) * (5 % 3)
+11 % 9
+Lists
+
+
+[] ⇔ empty list
+[1,2,3] ⇔ List of integral
+["foo","bar","baz"] ⇔ List of String
+1:[2,3] ⇔ [1,2,3], (:) prepend one element
+1:2:[] ⇔ [1,2]
+[1,2] ++ [3,4] ⇔ [1,2,3,4], (++) concatenate
+[1,2,3] ++ ["foo"] ⇔ ERROR String ≠ Integral
+[1..4] ⇔ [1,2,3,4]
+[1,3..10] ⇔ [1,3,5,7,9]
+[2,3,5,7,11..100] ⇔ ERROR! I am not so smart!
+[10,9..1] ⇔ [10,9,8,7,6,5,4,3,2,1]
+Strings
+
+Char.
+'a' :: Char
+"a" :: [Char]
+"" ⇔ []
+"ab" ⇔ ['a','b'] ⇔ 'a':"b" ⇔ 'a':['b'] ⇔ 'a':'b':[]
+"abc" ⇔ "ab"++"c"
+
+Data.Text instead. If you want to represent a stream of ASCII char, you should use Data.ByteString.
+Tuples
+
+(a,b). Elements in a tuple can have different types.
+-- All these tuples are valid
+(2,"foo")
+(3,'a',[2,3])
+((2,"a"),"c",3)
+
+fst (x,y) ⇒ x
+snd (x,y) ⇒ y
+
+fst (x,y,z) ⇒ ERROR: fst :: (a,b) -> a
+snd (x,y,z) ⇒ ERROR: snd :: (a,b) -> b
+Deal with parentheses
+
+($) and (.).
+-- By default:
+f g h x ⇔ (((f g) h) x)
+
+-- the $ replace parenthesis from the $
+-- to the end of the expression
+f g $ h x ⇔ f g (h x) ⇔ (f g) (h x)
+f $ g h x ⇔ f (g h x) ⇔ f ((g h) x)
+f $ g $ h x ⇔ f (g (h x))
+
+-- (.) the composition function
+(f . g) x ⇔ f (g x)
+(f . g . h) x ⇔ f (g (h x))
+
+Useful notations for functions
+
+
+x :: Int ⇔ x is of type Int
+x :: a ⇔ x can be of any type
+x :: Num a => a ⇔ x can be any type a
+ such that a belongs to Num type class
+f :: a -> b ⇔ f is a function from a to b
+f :: a -> b -> c ⇔ f is a function from a to (b→c)
+f :: (a -> b) -> c ⇔ f is a function from (a→b) to c^ uses infix notation. For each infix operator there its associated prefix notation. You just have to put it inside parenthesis.x in the left and right side! It’s called η-reduction.' in their name. Here:
+
+square ⇔ square' ⇔ square'' ⇔ square'''if .. then .. else Haskell notation is more like the ¤?¤:¤ C operator. You cannot forget the else.
+
+
+
+Hard Part
+
+
+Functional style
+
+
+
+
+
+
+[1,2,3,4,5] ⇒ 2 + 4 ⇒ 6
+function evenSum(list) {
+ var result = 0;
+ for (var i=0; i< list.length ; i++) {
+ if (list[i] % 2 ==0) {
+ result += list[i];
+ }
+ }
+ return result;
+}
+
+C version of the recursive function. Note that for simplicity I assume the int list ends with the first 0 value.
+int evenSum(int *list) {
+ return accumSum(0,list);
+}
+
+int accumSum(int n, int *list) {
+ int x;
+ int *xs;
+ if (*list == 0) { // if the list is empty
+ return n;
+ } else {
+ x = list[0]; // let x be the first element of the list
+ xs = list+1; // let xs be the list without x
+ if ( 0 == (x%2) ) { // if x is even
+ return accumSum(n+x, xs);
+ } else {
+ return accumSum(n, xs);
+ }
+ }
+}even verifies if a number is even.head returns the first element of a list:tail returns all elements of a list, except the first:l, l ⇔ (head l):(tail l)
+
+evenSum returns the sum of all even numbers in a list:
+
+
+ghci:
+% ghci
+GHCi, version 7.0.3: http://www.haskell.org/ghc/ :? for help
+Loading package ghc-prim ... linking ... done.
+Loading package integer-gmp ... linking ... done.
+Loading package base ... linking ... done.
+Prelude> :load 11_Functions.lhs
+[1 of 1] Compiling Main ( 11_Functions.lhs, interpreted )
+Ok, modules loaded: Main.
+*Main> evenSum [1..5]
+6
+
+
+*Main> evenSum [1..5]
+accumSum 0 [1,2,3,4,5]
+1 is odd
+accumSum 0 [2,3,4,5]
+2 is even
+accumSum (0+2) [3,4,5]
+3 is odd
+accumSum (0+2) [4,5]
+2 is even
+accumSum (0+2+4) [5]
+5 is odd
+accumSum (0+2+4) []
+l == []
+0+2+4
+0+6
+6
+
+
+
+where or let. This way our accumSum function won’t pollute the namespace of our module.
+
+
+
+
+
+
+
+
+
+foo l = if l == [] then <x> else <y> You simply state:
+
+l:
+
+
+
+
+
+
+
+Higher Order Functions
+
+
+
+
+
+filter :: (a -> Bool) -> [a] -> [a]
+map :: (a -> b) -> [a] -> [b]
+foldl :: (a -> b -> a) -> a -> [b] -> a
+-- Version 5
+evenSum l = mysum 0 (filter even l)
+ where
+ mysum n [] = n
+ mysum n (x:xs) = mysum (n+x) xsfilter takes a function of type (a -> Bool) and a list of type [a]. It returns a list containing only elements for which the function returned true.foldl function to accumulate a value as we pass through the list. The function foldl captures a general coding pattern:
+ myfunc list = foo initialValue list
+ foo accumulated [] = accumulated
+ foo tmpValue (x:xs) = foo (bar tmpValue x) xs
+
+
+myfunc list = foldl bar initialValue list
+
+foldl:(f z x) and simply pushes it onto the stack. This is why we generally use foldl' instead of foldl; foldl' is a strict version of foldl. If you don’t understand what lazy and strict means, don’t worry, just follow the code as if foldl and foldl' were identical.evenSum becomes:
+-- Version 6
+-- foldl' isn't accessible by default
+-- we need to import it from the module Data.List
+import Data.List
+evenSum l = foldl' mysum 0 (filter even l)
+ where mysum acc value = acc + valuemysum.
+
+
+
+
+
+-- Version 8
+import Data.List (foldl')
+evenSum :: Integral a => [a] -> a
+evenSum l = foldl' (+) 0 (filter even l)foldl' isn’t the easiest function to grasp. If you are not used to it, you should study it a bit.
+ evenSum [1,2,3,4]
+⇒ foldl' (+) 0 (filter even [1,2,3,4])
+⇒ foldl' (+) 0 [2,4]
+⇒ foldl' (+) (0+2) [4]
+⇒ foldl' (+) 2 [4]
+⇒ foldl' (+) (2+4) []
+⇒ foldl' (+) 6 []
+⇒ 6
+
+(.). The (.) function corresponds to mathematical composition.
+-- Version 9
+import Data.List (foldl')
+evenSum :: Integral a => [a] -> a
+evenSum = (foldl' (+) 0) . (filter even)
+
+
+
+[1,2,3,4] ▷ [1,4,9,16] ▷ [4,16] ▷ 20
+map (^2) [1,2,3,4] ⇔ [1,4,9,16]map function simply applies a function to all the elements of a list.
+Types
+
+
+
+
+
+
+
+
+type Name = AnotherType is just an alias and the compiler doesn’t mark any difference between Name and AnotherType.data Name = NameConstructor AnotherType does mark a difference.data can construct structures which can be recursives.deriving is magic and creates functions for you.
+Type inference
+
+square function in Haskell:square any Numeral type. You can provide square with an Int, an Integer, a Float a Fractional and even Complex. Proof by example:
+% ghci
+GHCi, version 7.0.4:
+...
+Prelude> let square x = x*x
+Prelude> square 2
+4
+Prelude> square 2.1
+4.41
+Prelude> -- load the Data.Complex module
+Prelude> :m Data.Complex
+Prelude Data.Complex> square (2 :+ 1)
+3.0 :+ 4.0x :+ y is the notation for the complex (x + iy).
+int int_square(int x) { return x*x; }
+
+float float_square(float x) {return x*x; }
+
+complex complex_square (complex z) {
+ complex tmp;
+ tmp.real = z.real * z.real - z.img * z.img;
+ tmp.img = 2 * z.img * z.real;
+}
+
+complex x,y;
+y = complex_square(x);
+#include <iostream>
+#include <complex>
+using namespace std;
+
+template<typename T>
+T square(T x)
+{
+ return x*x;
+}
+
+int main() {
+ // int
+ int sqr_of_five = square(5);
+ cout << sqr_of_five << endl;
+ // double
+ cout << (double)square(5.3) << endl;
+ // complex
+ cout << square( complex<double>(5,3) )
+ << endl;
+ return 0;
+}
+
+
+
+
+Type construction
+
+
+
+
+
+
+
+showInfos and run the program:data.
+
+
+showInfos, the compiler complains! So this is a potential mistake you will never make again and the only price is to be more verbose.data is mainly:
+data DataTypeName = DataConstructor {
+ field1 :: [type of field1]
+ , field2 :: [type of field2]
+ ...
+ , fieldn :: [type of fieldn] }
+
+data Complex a = Num a => Complex { real :: a, img :: a}
+c = Complex 1.0 2.0
+z = Complex { real = 3, img = 4 }
+real c ⇒ 1.0
+img z ⇒ 4
+
+
+Recursive type
+
+infixr gives the precedence.Show), read (Read), test equality (Eq) and compare (Ord) your new data structure you can tell Haskell to derive the appropriate functions for you.deriving (Show) to your data declaration, Haskell creates a show function for you. We’ll see soon how you can use your own show function.
+
+0 ::: (1 ::: Nil)
+0 ::: (1 ::: Nil)
+
+
+Trees
+
+
+
+
+
+
+
+
+
+
+(x:xs) will be converted to a tree where:
+
+
xxs which are strictly inferior to x andxs which are strictly superior to x.
+Node 7 (Node 2 Empty (Node 4 Empty Empty)) (Node 8 Empty Empty)
+
+deriving (Show) from the declaration of our BinTree type. And it might also be useful to make our BinTree an instance of (Eq and Ord) so we will be able to test equality and compare trees.deriving (Show), Haskell doesn’t create a show method for us. We will create our own version of show. To achieve this, we must declare that our newly created type BinTree a is an instance of the type class Show. The general syntax is:
+
+
+-- declare BinTree a to be an instance of Show
+instance (Show a) => Show (BinTree a) where
+ -- will start by a '<' before the root
+ -- and put a : a begining of line
+ show t = "< " ++ replace '\n' "\n: " (treeshow "" t)
+ where
+ -- treeshow pref Tree
+ -- shows a tree and starts each line with pref
+ -- We don't display the Empty tree
+ treeshow pref Empty = ""
+ -- Leaf
+ treeshow pref (Node x Empty Empty) =
+ (pshow pref x)
+
+ -- Right branch is empty
+ treeshow pref (Node x left Empty) =
+ (pshow pref x) ++ "\n" ++
+ (showSon pref "`--" " " left)
+
+ -- Left branch is empty
+ treeshow pref (Node x Empty right) =
+ (pshow pref x) ++ "\n" ++
+ (showSon pref "`--" " " right)
+
+ -- Tree with left and right children non empty
+ treeshow pref (Node x left right) =
+ (pshow pref x) ++ "\n" ++
+ (showSon pref "|--" "| " left) ++ "\n" ++
+ (showSon pref "`--" " " right)
+
+ -- shows a tree using some prefixes to make it nice
+ showSon pref before next t =
+ pref ++ before ++ treeshow (pref ++ next) t
+
+ -- pshow replaces "\n" by "\n"++pref
+ pshow pref x = replace '\n' ("\n"++pref) (show x)
+
+ -- replaces one char by another string
+ replace c new string =
+ concatMap (change c new) string
+ where
+ change c new x
+ | x == c = new
+ | otherwise = x:[] -- "x"treeFromList method remains identical.
+
+
+
+Int binary tree:
+< 7
+: |--2
+: | |--1
+: | `--4
+: | |--3
+: | `--6
+: `--8
+: `--21
+: |--12
+: `--23< character. And each following line starts with a :. But we could also use another type.
+String binary tree:
+< "foo"
+: |--"bar"
+: | `--"baz"
+: `--"gor"
+: `--"yog"
+
+
+
+Binary tree of Char binary trees:
+< < 'b'
+: : |--'a'
+: : `--'z'
+: |--< 'b'
+: | : |--'a'
+: | : `--'r'
+: `--< 'z'
+: : `--'a'
+: : `--'r': (except for the root).
+
+
+
+
+
+
+print ( treeFromList (
+ map treeFromList
+ [ map treeFromList ["YO","DAWG"]
+ , map treeFromList ["I","HEARD"]
+ , map treeFromList ["I","HEARD"]
+ , map treeFromList ["YOU","LIKE","TREES"] ]))
+Binary tree of Binary trees of Char binary trees:
+< < < 'Y'
+: : : `--'O'
+: : `--< 'D'
+: : : |--'A'
+: : : `--'W'
+: : : `--'G'
+: |--< < 'I'
+: | : `--< 'H'
+: | : : |--'E'
+: | : : | `--'A'
+: | : : | `--'D'
+: | : : `--'R'
+: `--< < 'Y'
+: : : `--'O'
+: : : `--'U'
+: : `--< 'L'
+: : : `--'I'
+: : : |--'E'
+: : : `--'K'
+: : `--< 'T'
+: : : `--'R'
+: : : |--'E'
+: : : `--'S'"I","HEARD". We have this for (almost) free, because we have declared Tree to be an instance of Eq.
+
+Infinite Structures
+
+
+
+
+
+
+(a+(b*c)) then you first reduce + first, then you reduce the inner (b*c)
+
+
+numbers entirely, it evaluates elements only when needed.
+[1..] ⇔ [1,2,3,4...]
+[1,3..] ⇔ [1,3,5,7,9,11...]take which is equivalent to our take'.
+
+
+
+
+< 0
+: |-- 0
+: | |-- 0
+: | | |-- 0
+: | | `-- 0
+: | `-- 0
+: | |-- 0
+: | `-- 0
+: `-- 0
+: |-- 0
+: | |-- 0
+: | `-- 0
+: `-- 0
+: |-- 0
+: `-- 0
+
+
+map, but should work on BinTree instead of list. Here is such a function:
+
+
+map to other data structures, search for functor and fmap.
+
+
+
+
+< 0
+: |-- -1
+: | |-- -2
+: | | |-- -3
+: | | `-- -1
+: | `-- 0
+: | |-- -1
+: | `-- 1
+: `-- 1
+: |-- 0
+: | |-- -1
+: | `-- 1
+: `-- 2
+: |-- 1
+: `-- 3
+Hell Difficulty Part
+
+
+
+
+
+Deal With IO
+
+
+
+
+
+
+IO looks a lot like an imperative program:
+f :: IO a
+f = do
+ x <- action1
+ action2 x
+ y <- action3
+ action4 x y
+
+<- .IO *; in this example:
+
+
action1 :: IO baction2 x :: IO ()action3 :: IO caction4 x y :: IO ax :: b, y :: cIO a, this should help you choose. In particular you cannot use pure functions directly here. To use pure functions you could do action2 (purefunction x) for example.
+
+
+
+
+
+putStrLn :: String -> IO ()
+getLine :: IO String
+print :: Show a => a -> IO ()do block has a type of IO a.
+main = do
+ putStrLn "Enter ... " :: IO ()
+ getLine :: IO String
+ print Something :: IO ()
+
+<- symbol.
+do
+ x <- somethingsomething :: IO a then x :: a.IO: All lines in a do block must be of one of the two forms:
+action1 :: IO a
+ -- in this case, generally a = ()
+value <- action2 -- where
+ -- action2 :: IO b
+ -- value :: b
+
+ % runghc 02_progressive_io_example.lhs
+ Enter a list of numbers (separated by comma):
+ foo
+ Prelude.read: no parseMaybe. This is a very common type in Haskell.Maybe is a type which takes one parameter. Its definition is:maybeRead function is a great example of this. This is a function similar to the function read4, but if something goes wrong the returned value is Nothing. If the value is right, it returns Just <the value>. Don’t try to understand too much of this function. I use a lower level function than read: reads.
+
+
+Nothing. Otherwise, for example for “1,2,3”, it will return Just [1,2,3].
+
+
+
+
+
+do block remains of the form IO a. The only strange construction is error. I’ll just say here that error msg takes the needed type (here IO ()).IO in its type: main. This means main is impure. But main uses getListFromString which is pure. So it’s clear just by looking at declared types which functions are pure and which are impure.
+
+
+
+
+
+
+
+
+IO [Integer]. Such a type means that we retrieved a value of type [Integer] through some IO actions. Some people might explain while waving their hands:
+
+[Integer] inside an IO»IO. This was quite fast. Here are the main things to remember:
+
+do block, each expression must have the type IO a. You are then limited with regard to the range of expressions available. For example, getLine, print, putStrLn, etc…IO a type means: an IO action which returns an element of type a. IO represents actions; under the hood, IO a is the type of a function. Read the next section if you are curious.IO.
+
+
+
+getArgs.
+IO trick explained
+
+
+
+
+
+
+main is defined as a function which modifies the state of the world.
+main :: World -> World
+
+main w0 =
+ let (v1,w1) = action1 w0 in
+ let (v2,w2) = action2 v1 w1 in
+ let (v3,w3) = action3 v2 w2 in
+ action4 v3 w3w1, w2 and w3) which must be passed on to the next action.bind or (>>=). With bind we don’t need temporary names anymore.
+main =
+ action1 >>= action2 >>= action3 >>= action4
+main = do
+ v1 <- action1
+ v2 <- action2 v1
+ v3 <- action3 v2
+ action4 v3IO type? It looks a bit like magic.
+askUser :: IO [Integer]
+askUser = do
+ putStrLn "Enter a list of numbers (separated by commas):"
+ input <- getLine
+ let maybeList = getListFromString input in
+ case maybeList of
+ Just l -> return l
+ Nothing -> askUser
+
+main :: IO ()
+main = do
+ list <- askUser
+ print $ sum listwhile in Haskell. In fact, for dealing with IO, an imperative style is generally more appropriate.main is a function that potentially changes the state of the world. Its type is then something like:main. But the real type of main is closer to this one6:() type is the unit type. Nothing to see here.a is the type of the result. For example, a getChar function should have the type World -> (Char, World).f a b, you have many choices:
+
+a then b then f a bb then a then f a b.a and b in parallel then f a bprint will evaluate as:
+
+((),new world id).askUser function:
+askUser :: IO [Integer]
+askUser = do
+ putStrLn "Enter a list of numbers:"
+ input <- getLine
+ let maybeList = getListFromString input in
+ case maybeList of
+ Just l -> return l
+ Nothing -> askUser
+askUser w0 =
+ let (_,w1) = putStrLn "Enter a list of numbers:" in
+ let (input,w2) = getLine w1 in
+ let (l,w3) = case getListFromString input of
+ Just l -> (l,w2)
+ Nothing -> askUser w2
+ in
+ (l,w3)w? names.x argument isn’t needed. The output type is a couple, (answer, newWorldValue). Each function f must have a type similar to:actionN w :: (World) -> (a,World).
+
+
+let (x,w1) = action1 w0 in
+let (y,w2) = action2 x w1 in
+let (_,w1) = action1 w0 in
+let (y,w2) = action2 w1 in
+
+
+bind the two lines. Let’s define the bind function. Its type is quite intimidating at first:(World -> (a,World)) is the type for an IO action. Now let’s rename it for clarity:getLine is an IO action which takes world as a parameter and returns a couple (String, World). This can be summarized as: getLine is of type IO String, which we also see as an IO action which will return a String “embeded inside an IO”.print is also interesting. It takes one argument which can be shown. In fact it takes two arguments. The first is the value to print and the other is the state of world. It then returns a couple of type ((), World). This means that it changes the state of the world, but doesn’t yield any more data.IO a type helps us simplify the type of bind:bind takes two IO actions as parameters and returns another IO action.bind function:Show a => a -> (World -> ((), World)), we know res = () (unit type). If you didn’t see what was magic here, let’s try with three lines this time.
+let (line1,w1) = getLine w0 in
+let (line2,w2) = getLine w1 in
+let ((),w3) = print (line1 ++ line2) in
+((),w3)(>>=) instead of bind. (>>=) is an infix function like (+); reminder 3 + 4 ⇔ (+) 3 4
+do
+ x <- action1
+ y <- action2
+ z <- action3
+ ...x in action2 and x and y in action3.<-? Easy, another function blindBind:(>>) operator.putInIO is return. This is quite a bad name when you learn Haskell. return is very different from what you might be used to.
+
+
+askUser :: IO [Integer]
+askUser = do
+ putStrLn "Enter a list of numbers (separated by commas):"
+ input <- getLine
+ let maybeList = getListFromString input in
+ case maybeList of
+ Just l -> return l
+ Nothing -> askUser
+
+main :: IO ()
+main = do
+ list <- askUser
+ print $ sum list
+
+
+import Data.Maybe
+
+maybeRead :: Read a => String -> Maybe a
+maybeRead s = case reads s of
+ [(x,"")] -> Just x
+ _ -> Nothing
+getListFromString :: String -> Maybe [Integer]
+getListFromString str = maybeRead $ "[" ++ str ++ "]"
+askUser :: IO [Integer]
+askUser =
+ putStrLn "Enter a list of numbers (sep. by commas):" >>
+ getLine >>= \input ->
+ let maybeList = getListFromString input in
+ case maybeList of
+ Just l -> return l
+ Nothing -> askUser
+
+main :: IO ()
+main = askUser >>=
+ \list -> print $ sum list(>>) and (>>=).
+
+Monads
+
+
+
+
+IO is a monad. Being a monad means you have access to some syntactical sugar with the do notation. But mainly, you have access to a coding pattern which will ease the flow of your code.
+
+
+
+Monad is a type class. To be an instance of this type class, you must provide the functions (>>=) and return. The function (>>) is derived from (>>=). Here is how the type class Monad is declared (basically):
+class Monad m where
+ (>>=) :: m a -> (a -> m b) -> m b
+ return :: a -> m a
+
+ (>>) :: m a -> m b -> m b
+ f >> g = f >>= \_ -> g
+
+ -- You should generally safely ignore this function
+ -- which I believe exists for historical reasons
+ fail :: String -> m a
+ fail = error
+
+
+
+class is not your friend. A Haskell class is not a class of the kind you will find in object-oriented programming. A Haskell class has a lot of similarities with Java interfaces. A better word would have been typeclass, since that means a set of types. For a type to belong to a class, all functions of the class must be provided for this type.m must be a type that takes an argument. for example IO a, but also Maybe a, [a], etc…
+
+
+return a >>= k == k a
+m >>= return == m
+m >>= (\x -> k x >>= h) == (m >>= k) >>= h
+Maybe is a monad
+
+Monad. One of the easiest to describe is Maybe. If you have a sequence of Maybe values, you can use monads to manipulate them. It is particularly useful to remove very deep if..then..else.. constructions.
+
+
+deposit value account = account + value
+withdraw value account = account - value
+
+eligible :: (Num a,Ord a) => a -> Bool
+eligible account =
+ let account1 = deposit 100 account in
+ if (account1 < 0)
+ then False
+ else
+ let account2 = withdraw 200 account1 in
+ if (account2 < 0)
+ then False
+ else
+ let account3 = deposit 100 account2 in
+ if (account3 < 0)
+ then False
+ else
+ let account4 = withdraw 300 account3 in
+ if (account4 < 0)
+ then False
+ else
+ let account5 = deposit 1000 account4 in
+ if (account5 < 0)
+ then False
+ else
+ True
+
+main = do
+ print $ eligible 300 -- True
+ print $ eligible 299 -- False
+
+
+
+deposit :: (Num a) => a -> a -> Maybe a
+deposit value account = Just (account + value)
+
+withdraw :: (Num a,Ord a) => a -> a -> Maybe a
+withdraw value account = if (account < value)
+ then Nothing
+ else Just (account - value)
+
+eligible :: (Num a, Ord a) => a -> Maybe Bool
+eligible account = do
+ account1 <- deposit 100 account
+ account2 <- withdraw 200 account1
+ account3 <- deposit 100 account2
+ account4 <- withdraw 300 account3
+ account5 <- deposit 1000 account4
+ Just True
+
+main = do
+ print $ eligible 300 -- Just True
+ print $ eligible 299 -- Nothing
+
+
+
+deposit :: (Num a) => a -> a -> Maybe a
+deposit value account = Just (account + value)
+
+withdraw :: (Num a,Ord a) => a -> a -> Maybe a
+withdraw value account = if (account < value)
+ then Nothing
+ else Just (account - value)
+
+eligible :: (Num a, Ord a) => a -> Maybe Bool
+eligible account =
+ deposit 100 account >>=
+ withdraw 200 >>=
+ deposit 100 >>=
+ withdraw 300 >>=
+ deposit 1000 >>
+ return True
+
+main = do
+ print $ eligible 300 -- Just True
+ print $ eligible 299 -- NothingMaybe can be used in most imperative languages. In fact, this is the kind of construction we make naturally.
+
+Nothing will stop the complete evaluation. This means you don’t execute all lines. You get this for free, thanks to laziness.(>>=) for Maybe in mind:
+instance Monad Maybe where
+ (>>=) :: Maybe a -> (a -> Maybe b) -> Maybe b
+ Nothing >>= _ = Nothing
+ (Just x) >>= f = f x
+
+ return x = Just xMaybe monad proved to be useful while being a very simple example. We saw the utility of the IO monad. But now for a cooler example, lists.
+
+The list monad
+
+
+
+
+
+
+
+
+[(1,1,7),(1,1,8),(1,1,9),(1,1,10),(1,2,9),(1,2,10)]
+
+
+Appendix
+
+
+
+More on Infinite Tree
+
+
+
+treeFromList
+
+
+treeTakeDepth:
+
+
+
+
+
+
+% runghc 02_Hard_Part/41_Infinites_Structures.lhs
+take 10 shuffle
+[3123,1915,707,3830,2622,1414,206,3329,2121,913]
+treeTakeDepth 4 (treeFromList shuffle)
+
+< 3123
+: |--1915
+: | |--707
+: | | |--206
+: | | `--1414
+: | `--2622
+: | |--2121
+: | `--2828
+: `--3830
+: |--3329
+: | |--3240
+: | `--3535
+: `--4036
+: |--3947
+: `--4242filter (<1) [2..]. But filter is not smart enought to understand that the result is the empty list.
+
+n so that treeTakeDepth n (treeFromList shuffle) will enter an infinite loop.n.shuffle list so that, for any depth, the program ends.
+treeFromList and shuffle function.shuffle. We generated only 4331 different numbers. To resolve this we make a slightly better shuffle function.
+
+
+filter (<x) xs is empty. Then to resolve this problem, I’ll authorize some error in the creation of our binary tree. This new version of code can create binary tree which don’t have the following property for some of its nodes:
+
+treeFromList. We simply have replaced filter by safefilter.
+
+
+safefilter is almost equivalent to filter but don’t enter infinite loop if the result is a finite list. If it cannot find an element for which the test is true after 10000 consecutive steps, then it considers to be the end of the search.
+
+
+
+
+
+8 to 100. It will work without killing your RAM! The flow and the memory management is done naturally by Haskell.
+
+deep and nbTry, it seems to work nicely. But in the worst case, it can be exponential. Create a worst case list to give as parameter to treeFromList.
+hint: think about ([0,-1,-1,....,-1,1,-1,...,-1,1,...]).safefilter as follow:
+
+safefilter' f l = if filter f (take 10000 l) == []
+ then []
+ else filter f l
+
+Explain why it doesn’t work and can enter into an infinite loop.shuffle is real random list with growing bounds. If you study a bit this structure, you’ll discover that with probability 1, this structure is finite. Using the following code (suppose we could use safefilter' directly as if was not in the where of safefilter) find a definition of f such that with probability 1, treeFromList' shuffle is infinite. And prove it. Disclaimer, this is only a conjecture.
+treeFromList' [] n = Empty
+treeFromList' (x:xs) n = Node x left right
+ where
+ left = treeFromList' (safefilter' (<x) xs (f n)
+ right = treeFromList' (safefilter' (>x) xs (f n)
+ f = ???Thanks
+/r/haskell and /r/programming. Your comment were most than welcome.
+
+
+eval function, that is applied to a string containing JSON.↩data IO a = IO {unIO :: State# RealWorld -> (# State# RealWorld, a #)}. All the # has to do with optimisation and I swapped the fields in my example. But this is the basic idea.↩
+
+
+
+
+
+
+
+ Published on 2012-02-08
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/Higher-order-function-in-zsh/code/functional.sh b/src/Scratch/en/blog/Higher-order-function-in-zsh/code/functional.sh
new file mode 100644
index 0000000..bf99fa3
--- /dev/null
+++ b/src/Scratch/en/blog/Higher-order-function-in-zsh/code/functional.sh
@@ -0,0 +1,62 @@
+#!/usr/bin/env zsh
+
+# Provide higer-order functions
+
+# usage:
+#
+# $ foo(){print "x: $1"}
+# $ map foo a b c d
+# x: a
+# x: b
+# x: c
+# x: d
+function map {
+ local func_name=$1
+ shift
+ for elem in $@; print -- $(eval $func_name $elem)
+}
+
+# $ bar() { print $(($1 + $2)) }
+# $ fold bar 0 1 2 3 4 5
+# 15
+# -- but also
+# $ fold bar 0 $( seq 1 100 )
+function fold {
+ if (($#<2)) {
+ print -- "ERROR fold use at least 2 arguments" >&2
+ return 1
+ }
+ if (($#<3)) {
+ print -- $2
+ return 0
+ } else {
+ local acc
+ local right
+ local func_name=$1
+ local init_value=$2
+ local first_value=$3
+ shift 3
+ right=$( fold $func_name $init_value $@ )
+ acc=$( eval "$func_name $first_value $right" )
+ print -- $acc
+ return 0
+ }
+}
+
+# usage:
+#
+# $ baz() { print $1 | grep baz }
+# $ filter baz titi bazaar biz
+# bazaar
+function filter {
+ local predicate=$1
+ local result
+ typeset -a result
+ shift
+ for elem in $@; do
+ if eval $predicate $elem >/dev/null; then
+ result=( $result $elem )
+ fi
+ done
+ print $result
+}
diff --git a/src/Scratch/en/blog/Higher-order-function-in-zsh/index.html b/src/Scratch/en/blog/Higher-order-function-in-zsh/index.html
new file mode 100644
index 0000000..bd1c22c
--- /dev/null
+++ b/src/Scratch/en/blog/Higher-order-function-in-zsh/index.html
@@ -0,0 +1,254 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Tips in avoiding Haskell Success at all cost
+
+
+
+
+
+
+
+
+
+
+
+Prevent Interest from beginner
+
+
+
+
+
+
+
+
+
+
+Make it difficult to install
+
+
+stack, cabal freeze, … While Nix is great, forcing new user completely alien to all these concepts to first learn it before starting to write their first line of code can greatly reduce their enthusiasm. Bonus point if you make them believe you can only program in Haskell on NixOS.Make it difficult to learn
+Make new comers feel dumb
+
+
+Tutorial authors
+
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE TypeOperators #-}
+
+module App where
+
+import Control.Monad.Trans.Except
+import Data.Aeson
+import GHC.Generics
+import Network.Wai
+import Network.Wai.Handler.Warp
+import Servant
+import System.IO
+
+type ItemApi =
+ "item" :> Get '[JSON] [Item] :<|>
+ "item" :> Capture "itemId" Integer :> Get '[JSON] Item
+
+itemApi :: Proxy ItemApi
+itemApi = Proxy
+
+run :: IO ()
+run = do
+ let port = 3000
+ settings =
+ setPort port $
+ setBeforeMainLoop (hPutStrLn stderr ("listening on port " ++ show port)) $
+ defaultSettings
+ runSettings settings =<< mkApp
+
+mkApp :: IO Application
+mkApp = return $ serve itemApi server
+
+server :: Server ItemApi
+server =
+ getItems :<|>
+ getItemById
+
+type Handler = ExceptT ServantErr IO
+
+getItems :: Handler [Item]
+getItems = return [exampleItem]
+
+getItemById :: Integer -> Handler Item
+getItemById = \ case
+ 0 -> return exampleItem
+ _ -> throwE err404
+
+exampleItem :: Item
+exampleItem = Item 0 "example item"
+
+data Item
+ = Item {
+ itemId :: Integer,
+ itemText :: String
+ }
+ deriving (Eq, Show, Generic)
+
+instance ToJSON Item
+instance FromJSON Item
+
+
+
:<|>'[] instead of []Proxy$deriving ha ha! You’ll need to explain typeclasses first!getItemByIdinstance ToJSON Item is great. But insist that we achieved to serve a JSON with extreme elegance and simplicity. Keep insisting on the simplicity and forgot to mention type safety which is one of the main benefit of Servant.
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE TemplateHaskell #-}
+
+import Control.Lens.TH (makePrisms)
+import GHC.Generics (Generic)
+import Lens.Family.Total
+
+data Example a b c = C1 a | C2 b | C3 c deriving (Generic)
+
+makePrisms ''Example
+
+instance (Empty a, Empty b, Empty c) => Empty (Example a b c)
+
+example :: Example String Char Int -> String
+example = _case
+ & on _C1 (\s -> s )
+ & on _C2 (\c -> replicate 3 c )
+ & on _C3 (\n -> replicate n '!')Library authors
+
+
+log :: Level -> String -> IO () by (<=.=$$.).
+
+unsafePerformIO as much as possibleConclusion & Mistake
+avoid success $ at all cost but to avoid $ success at all cost1.
+
+
+
+
+
+
+
+
+
+
+ Published on 2016-10-01
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/Holy-Haskell-Starter/index.html b/src/Scratch/en/blog/Holy-Haskell-Starter/index.html
new file mode 100644
index 0000000..8ec709b
--- /dev/null
+++ b/src/Scratch/en/blog/Holy-Haskell-Starter/index.html
@@ -0,0 +1,959 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Higher order function in zsh
+
+
+
+
+
+
+
+
+
+
+
+map if you use external function. mapl to use lambda function. And mapa for arithmetic operations.
+$ filterl 'echo $1|grep a >/dev/null' ab cd ef ada
+ab
+ada
+
+$ folda '$1+$2' {1..5}
+15
+
+$ folda '$1*$2' {1..20}
+2432902008176640000
+
+$ mapl 'echo X $1:t Y' ~/.zsh/functional/src/*
+X each Y
+X filter Y
+X fold Y
+X map Y
+
+$ mapa '$1*2' {1..3}
+2
+4
+6
+
+$ mapl 'echo result $1' $(mapa '$1+5' $(mapa '$1*2' {1..3}))
+result 7
+result 9
+result 11map, filter and fold.
+# for each directory in projects dir
+for toProject in /path/to/projects/*(/N); do
+ # toProject is /path/to/projects/foo
+ # project become foo (:t for tail)
+ project=${toProject:t}
+ for toResource in $toProject/resources/*.gif(.N); do
+ convert $toResource ${toResource:r}.png && \
+ \rm -f $toResource
+ done
+done
+
+(/N) means to select only directory and not to crash if there isn’t any.(.N) means to select only files and not to crash if there isn’t any.:t means tail; if toto=/path/to/file.ext then ${toto:t}=file.ext.
+gif_to_png() { convert $1 ${1:r}.png && \rm -f $1 }
+
+handle_resources() { map gif_to_png $1/resources/*.gif(.N) }
+
+map handle_resources /path/to/projects/*(/N)s which their name contains their project name:
+for toProject in Projects/*; do
+ project=$toProject:t
+ if print -- project | grep -v s >/dev/null
+ then
+ print $project
+ for toResource in $toProject/*(.N); do
+ if print -- ${toResource:t} | grep $project >/dev/null; then
+ print -- "X $toResource"
+ fi
+ done
+ fi
+done
+contain_no_s() { print $1 | grep -v s }
+
+function verify_file_name {
+ local project=$1:t
+ contains_project_name() { print $1:t | grep $project }
+ map "print -- X" $(filter contains_project_name $1/*(.N))
+}
+
+map verify_file_name $( filter contain_no_s Projects/* )
+ #!/usr/bin/env zsh
+
+# Provide higer-order functions
+
+# usage:
+#
+# $ foo(){print "x: $1"}
+# $ map foo a b c d
+# x: a
+# x: b
+# x: c
+# x: d
+function map {
+ local func_name=$1
+ shift
+ for elem in $@; print -- $(eval $func_name $elem)
+}
+
+# $ bar() { print $(($1 + $2)) }
+# $ fold bar 0 1 2 3 4 5
+# 15
+# -- but also
+# $ fold bar 0 $( seq 1 100 )
+function fold {
+ if (($#<2)) {
+ print -- "ERROR fold use at least 2 arguments" >&2
+ return 1
+ }
+ if (($#<3)) {
+ print -- $2
+ return 0
+ } else {
+ local acc
+ local right
+ local func_name=$1
+ local init_value=$2
+ local first_value=$3
+ shift 3
+ right=$( fold $func_name $init_value $@ )
+ acc=$( eval "$func_name $first_value $right" )
+ print -- $acc
+ return 0
+ }
+}
+
+# usage:
+#
+# $ baz() { print $1 | grep baz }
+# $ filter baz titi bazaar biz
+# bazaar
+function filter {
+ local predicate=$1
+ local result
+ typeset -a result
+ shift
+ for elem in $@; do
+ if eval $predicate $elem >/dev/null; then
+ result=( $result $elem )
+ fi
+ done
+ print $result
+}
+
+
+
+
+
+
+
+ Published on 2011-09-28
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/Learn-Vim-Progressively/index.html b/src/Scratch/en/blog/Learn-Vim-Progressively/index.html
new file mode 100644
index 0000000..7c042ce
--- /dev/null
+++ b/src/Scratch/en/blog/Learn-Vim-Progressively/index.html
@@ -0,0 +1,384 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Holy Haskell Project Starter
+ A Haskell tutorial: from nothing to something useful
+
+
+
+
+
+
+
+
+
+
+
+zsh in Haskell using its own result.
+
+git and generally hosting it on github. Also, it is recommended to use cabal sandboxes. And as bonus, an auto-update tool that recompile and retest on each file save.
+
+cabal update && cabal install holy-project.
+
+
+cabal-install (at least 1.18)
+
+
+# Download the script
+git clone https://github.com/yogsototh/init-haskell-project.git
+# Copy the script in a directory of you PATH variable
+cp init-haskell-project/holy-haskell.sh ~/bin
+# Go to the directory containing all your projects
+cd my/projects/directory
+# Launch thcript
+holy-haskell.shcabal init doesn’t do?
+
+git with the right .gitignore file.tasty to organize your tests (HUnit, QuickCheck and SmallCheck).-Wall for ghc compilation.
+zsh really?
+
+
+zsh was easy. But considering its size, it is worth to rewrite it in Haskell. Furthermore, it will be a good exercise.Patricide
+holy-haskell.sh:
+> ./holy-haskell.sh
+Bridgekeeper: Stop!
+Bridgekeeper: Who would cross the Bridge of Death
+Bridgekeeper: must answer me these questions three,
+Bridgekeeper: ere the other side he see.
+You: Ask me the questions, bridgekeeper, I am not afraid.
+
+Bridgekeeper: What is the name of your project?
+> Holy project
+Bridgekeeper: What is your name? (Yann Esposito (Yogsototh))
+>
+Bridgekeeper: What is your email? (Yann.Esposito@gmail.com)
+>
+Bridgekeeper: What is your github user name? (yogsototh)
+>
+Bridgekeeper: What is your project in less than ten words?
+> Start your Haskell project with cabal, git and tests.
+Initialize git
+Initialized empty Git repository in .../holy-project/.git/
+Create files
+ .gitignore
+ holy-project.cabal
+ Setup.hs
+ LICENSE (MIT)
+ test/Test.hs
+ test/HolyProject/Swallow/Test.hs
+ src/HolyProject/Swallow.hs
+ test/HolyProject/Coconut/Test.hs
+ src/HolyProject/Coconut.hs
+ src/HolyProject.hs
+ src/Main.hs
+Cabal sandboxing, install and test
+...
+ many compilations lines
+...
+Running 1 test suites...
+Test suite Tests: RUNNING...
+Test suite Tests: PASS
+Test suite logged to: dist/test/holy-project-0.1.0.0-Tests.log
+1 of 1 test suites (1 of 1 test cases) passed.
+All Tests
+ Swallow
+ swallow test: OK
+ coconut
+ coconut: OK
+ coconut property: OK
+ 148 tests completed
+
+All 3 tests passed
+
+
+
+Bridgekeeper: What... is the air-speed velocity of an unladen swallow?
+You: What do you mean? An African or European swallow?
+Bridgekeeper: Huh? I... I don't know that.
+[the bridgekeeper is thrown over]
+Bridgekeeper: Auuuuuuuuuuuugh
+Sir Bedevere: How do you know so much about swallows?
+You: Well, you have to know these things when you're a king, you know.
+
+
+
+
+
+~/.gitconfig file in order to provide a default name and email.tmux on Linux or the splits in iTerm 2 on Mac OS X. Now, any modification of a source file will relaunch a compilation and a test.The dialogs
+
+
+
+zsh:
+# init colors
+autoload colors
+colors
+for COLOR in RED GREEN YELLOW BLUE MAGENTA CYAN BLACK WHITE; do
+ eval $COLOR='$fg_no_bold[${(L)COLOR}]'
+ eval BOLD_$COLOR='$fg_bold[${(L)COLOR}]'
+done
+eval RESET='$reset_color'
+# functions
+bk(){print -- "${GREEN}Bridgekeeper: $*${RESET}"}
+bkn(){print -n -- "${GREEN}Bridgekeeper: $*${RESET}"}
+you(){print -- "${YELLOW}You: $*${RESET}"}
+...
+# the introduction dialog
+bk "Stop!"
+bk "Who would cross the Bridge of Death"
+bk "must answer me these questions three,"
+bk "ere the other side he see."
+you "Ask me the questions, bridgekeeper, I am not afraid.\n"
+...
+# the final dialog
+print "\n\n"
+bk "What... is the air-speed velocity of an unladen swallow?"
+you "What do you mean? An African or European swallow?"
+bk "Huh? I... I don't know that."
+log "[the bridgekeeper is thrown over]"
+bk "Auuuuuuuuuuuugh"
+log "Sir Bedevere: How do you know so much about swallows?"
+you "Well, you have to know these things when you're a king, you know."
+bk :: String -> IO ()
+bk str = putStrLn $ "Bridgekeeper: " ++ str
+
+bkn :: String -> IO ()
+bkn str = pustStr $ "Bridgekeeper: " ++ str
+
+you :: String -> IO ()
+you str = putStrLn $ "You: " ++ str
+
+intro :: IO ()
+intro = do
+ bk "Stop!"
+ bk "Who would cross the Bridge of Death"
+ bk "must answer me these questions three,"
+ bk "ere the other side he see."
+ you "Ask me the questions, bridgekeeper, I am not afraid.\n"
+
+end :: IO ()
+end = do
+ putStrLn "\n\n"
+ bk "What... is the air-speed velocity of an unladen swallow?"
+ you "What do you mean? An African or European swallow?"
+ bk "Huh? I... I don't know that."
+ putStrLn "[the bridgekeeper is thrown over]"
+ bk "Auuuuuuuuuuuugh"
+ putStrLn "Sir Bedevere: How do you know so much about swallows?"
+ you "Well, you have to know these things when you're a king, you know."ansi-terminal package. So we have to add ansi-terminal as a build dependency in our cabal file.holy-project.cabal to add it.
+...
+build-depends: base >=4.6 && <4.7
+ , ansi-terminal
+...
+import System.Console.ANSI
+
+colorPutStr :: Color -> String -> IO ()
+colorPutStr color str = do
+ setSGR [ SetColor Foreground Dull color
+ , SetConsoleIntensity NormalIntensity
+ ]
+ putStr str
+ setSGR []
+
+
+bk :: String -> IO ()
+bk str = colorPutStr Green ("Bridgekeeper: " ++ str ++ "\n")
+bkn :: String -> IO ()
+bkn str = colorPutStr Green ("Bridgekeeper: " ++ str)
+you :: String -> IO ()
+you str = colorPutStr Yellow ("You: " ++ str ++ "\n")
+
+intro :: IO ()
+intro = do
+ bk "Stop!"
+ bk "Who would cross the Bridge of Death"
+ bk "must answer me these questions three,"
+ bk "ere the other side he see."
+ you "Ask me the questions, bridgekeeper, I am not afraid.\n"
+
+end :: IO ()
+end = do
+ putStrLn "\n\n"
+ bk "What... is the air-speed velocity of an unladen swallow?"
+ you "What do you mean? An African or European swallow?"
+ bk "Huh? I... I don't know that."
+ putStrLn "[the bridgekeeper is thrown over]"
+ bk "Auuuuuuuuuuuugh"
+ putStrLn "Sir Bedevere: How do you know so much about swallows?"
+ you "Well, you have to know these things when you're a king, you know."src/Main.hs. Declare a main function:
+main :: IO ()
+main = do
+ intro
+ endcabal install and run cabal run (or ./.cabal-sandbox/bin/holy-project). It works!Five Questions – Three questions Sir!
+
+
+
+
+answer=""
+ask(){
+ local info="$1"
+ bk "What is your $info?"
+ print -n "> "
+ read answer
+}
+...
+ask name
+name="$answer"
+import System.IO (hFlush, stdout)
+...
+ask :: String -> IO String
+ask info = do
+ bk $ "What is your " ++ info ++ "?"
+ putStr "> "
+ hFlush stdout -- Because we want to ask on the same line.
+ getLine
+main = do
+ intro
+ _ <- ask "project name"
+ _ <- ask "name"
+ _ <- ask "email"
+ _ <- ask "github account"
+ _ <- ask "project in less than a dozen word"
+ endcabal install and then ./.cabal-sandbox/bin/holy-project..gitconfig file and the github API.Using answers
+
+
+
+Create the project name
+split package):
+import Data.Char (toLower)
+import Data.List (intercalate)
+import Data.List.Split (splitOneOf)
+...
+projectNameFromString :: String -> String
+projectNameFromString str = intercalate "-" (splitOneOf " -" (map toLower str))
+zsh:
+"Holy grail" ==( ${project:gs/ /-/} )=> "Holy-grail"
+ ==( ${project:l} )=> "holy-grail"
+
+haskell
+"Holy grail" ==( map toLower )=> "holy grail"
+ ==( splitOneOf " -" )=> ["holy","grail"]
+ ==( intercalate "-" )=> "holy-grail"Create the module name
+
+# Capitalize a string
+capitalize(){
+ local str="$(print -- "$*" | sed 's/-/ /g')"
+ print -- ${(C)str} | sed 's/ //g'
+}
+-- | transform a chain like "Holy project" in "HolyProject"
+capitalize :: String -> String
+capitalize str = concatMap capitalizeWord (splitOneOf " -" str)
+ where
+ capitalizeWord :: String -> String
+ capitalizeWord (x:xs) = toUpper x:map toLower xs
+ capitalizeWord _ = []concatMap as map and concat):
+shell:
+"Holy-grail" ==( sed 's/-/ /g' )=> "Holy grail"
+ ==( ${(C)str} )=> "Holy Grail"
+ ==( sed 's/ //g' )=> "HolyGrail"
+
+haskell:
+"Holy-grail" ==( splitOneOf " -" )=> ["Holy","grail"]
+ ==( map capitalizeWord )=> ["Holy","Grail"]
+ ==( concat )=> "HolyGrail"Check the project name
+
+ioassert :: Bool -> String -> IO ()
+ioassert True _ = return ()
+ioassert False str = error str
+
+main :: IO ()
+main = do
+ intro
+ project <- ask "project name"
+ ioassert (checkProjectName project)
+ "Use only letters, numbers, spaces and dashes please"
+ let projectname = projectNameFromString project
+ modulename = capitalize project
+-- | verify if project name is conform
+checkProjectName :: String -> Bool
+checkProjectName [] = False
+checkProjectName str =
+ all (\c -> isLetter c || isNumber c || c=='-' || c==' ') strCreate the project
+
+
+
+hastache, a Haskell implementation of Mustache templates3.Add external files in a cabal project
+Data-Files: entry in the header of the cabal file:
+data-files: scaffold/LICENSE
+ , scaffold/Setup.hs
+ , scaffold/auto-update
+ , scaffold/gitignore
+ , scaffold/interact
+ , scaffold/project.cabal
+ , scaffold/src/Main.hs
+ , scaffold/src/ModuleName.hs
+ , scaffold/src/ModuleName/Coconut.hs
+ , scaffold/src/ModuleName/Swallow.hs
+ , scaffold/test/ModuleName/Coconut/Test.hs
+ , scaffold/test/ModuleName/Swallow/Test.hs
+ , scaffold/test/Test.hs
+The MIT License (MIT)
+
+Copyright (c) {{year}} {{author}}
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+...{{year}} and {{author}} at runtime. We have to find the files. Cabal will create a module named Paths_holy_project. If we import this module we have the function genDataFileName at our disposal. Now we can read the files at runtime like this:
+ ...
+ do
+ pkgFilePath <- getDataFileName "scaffold/LICENSE"
+ templateContent <- readFile pkgFilePath
+ ...Create files and directories
+/ isn’t considered as a subdirectory character. To resolve this problem we will use FilePath:
+import System.Directory
+import System.FilePath.Posix (takeDirectory,(</>))
+...
+createProject ... = do
+ ...
+ createDirectory projectName -- mkdir
+ setCurrentDirectory projectName -- cd
+ genFile "LICENSE" "LICENSE"
+ genFile "gitignore" ".gitignore"
+ genFile "src/Main.hs" ("src" </> "Main.hs")
+
+genFile dataFilename outputFilename = do
+ pkgfileName <- getDataFileName ("scaffold/" ++ filename)
+ template <- readFile pkgfileName
+ transformedFile <- ??? -- hastache magic here
+ createDirectoryIfMissing True (takeDirectory outputFileName)
+ writeFile outputFileName transformedFileUse Hastache
+
+{-# LANGUAGE DeriveDataTypeable #-}
+...
+import Data.Data
+import Text.Hastache
+import Text.Hastache.Context
+import qualified Data.ByteString as BS
+import qualified Data.ByteString.Lazy.Char8 as LZ
+data Project = Project {
+ projectName :: String
+ , moduleName :: String
+ , author :: String
+ , mail :: String
+ , ghaccount :: String
+ , synopsis :: String
+ , year :: String
+ } deriving (Data, Typeable)
+main :: IO ()
+main = do
+ intro
+ project <- ask "project name"
+ ioassert (checkProjectName project)
+ "Use only letters, numbers, spaces and dashes please"
+ let projectname = projectNameFromString project
+ modulename = capitalize project
+ in_author <- ask "name"
+ in_email <- ask "email"
+ in_ghaccount <- ask "github account"
+ in_synopsis <- ask "project in less than a dozen word?"
+ current_year <- getCurrentYear
+ createProject $ Project projectname modulename in_author in_email
+ in_ghaccount in_synopsis current_year
+ end
+createProject :: Project -> IO ()
+createProject p = do
+ let context = mkGenericContext p
+ createDirectory (projectName p)
+ setCurrentDirectory (projectName p)
+ genFile context "gitignore" $ ".gitignore"
+ genFile context "project.cabal" $ (projectName p) ++ ".cabal"
+ genFile context "src/Main.hs") $ "src" </> "Main.hs"
+ ...
+
+genFile :: MuContext IO -> FilePath -> FilePath -> IO ()
+genFile context filename outputFileName = do
+ pkgfileName <- getDataFileName ("scaffold/"++filename)
+ template <- BS.readFile pkgfileName
+ transformedFile <- hastacheStr defaultConfig template context
+ createDirectoryIfMissing True (takeDirectory outputFileName)
+ LZ.writeFile outputFileName transformedFileGit and Cabal
+
+
+
+system function.
+import System.Cmd
+
+...
+main = do
+ ...
+ _ <- system "git init ."
+ _ <- system "cabal sandbox init"
+ _ <- system "cabal install"
+ _ <- system "cabal test"
+ _ <- system $ "./.cabal-sandbox/bin/test-" ++ projectNameAmeliorations
+Better error message
+
+
+
+
+import System.Random
+
+holyError :: String -> IO ()
+holyError str = do
+ r <- randomIO
+ if r
+ then
+ do
+ bk "What... is your favourite colour?"
+ you "Blue. No, yel..."
+ putStrLn "[You are thrown over the edge into the volcano]"
+ you "You: Auuuuuuuuuuuugh"
+ bk " Hee hee heh."
+ else
+ do
+ bk "What is the capital of Assyria?"
+ you "I don't know that!"
+ putStrLn "[You are thrown over the edge into the volcano]"
+ you "Auuuuuuuuuuuugh"
+ error ('\n':str)
+ioassert :: Bool -> String -> IO ()
+ioassert True _ = return ()
+ioassert False str = holyError strUse
+.gitconfig~/.gitconfig file content and see if it contains a name and email information. We will need to access to the HOME environment variable. Also, as we use bytestring package for hastache, let’s take advantage of this library.
+import Data.Maybe (fromJust)
+import System.Environment (getEnv)
+import Control.Exception
+import System.IO.Error
+import Control.Monad (guard)
+
+safeReadGitConfig :: IO LZ.ByteString
+safeReadGitConfig = do
+ e <- tryJust (guard . isDoesNotExistError)
+ (do
+ home <- getEnv "HOME"
+ LZ.readFile $ home ++ "/.gitconfig" )
+ return $ either (const (LZ.empty)) id e
+...
+main = do
+ gitconfig <- safeReadGitConfig
+ let (name,email) = getNameAndMail gitconfig
+ project <- ask "project name" Nothing
+ ...
+ in_author <- ask "name" name
+ ...
+ask :: String -> Maybe String -> IO String
+ask info hint = do
+ bk $ "What is your " ++ info ++ "?" ++ (maybe "" (\h -> " ("++h++")") hint)
+ ....gitconfig, it is quite minimalist.
+getNameAndMail :: LZ.ByteString -> (Maybe String,Maybe String)
+getNameAndMail gitConfigContent = (getFirstValueFor splitted "name",
+ getFirstValueFor splitted "email")
+ where
+ -- make lines of words
+ splitted :: [[LZ.ByteString]]
+ splitted = map LZ.words (LZ.lines gitConfigContent)
+
+-- Get the first line which start with
+-- 'elem =' and return the third field (value)
+getFirstValueFor :: [[LZ.ByteString]] -> String -> Maybe String
+getFirstValueFor splitted key = firstJust (map (getValueForKey key) splitted)
+
+-- return the first Just value of a list of Maybe
+firstJust :: (Eq a) => [Maybe a] -> Maybe a
+firstJust l = case dropWhile (==Nothing) l of
+ [] -> Nothing
+ (j:_) -> j
+
+-- Given a line of words ("word1":"word2":rest)
+-- getValue will return rest if word1 == key
+-- 'elem =' or Nothing otherwise
+getValueForKey :: String -- key
+ -> [LZ.ByteString] -- line of words
+ -> Maybe String -- the value if found
+getValueForKey el (n:e:xs) = if (n == (LZ.pack el)) && (e == (LZ.pack "="))
+ then Just (LZ.unpack (LZ.unwords xs))
+ else Nothing
+getValueForKey _ _ = NothinggetNameAndMail doesn’t read the full file and stop at the first occurrence of name and mail.Use the github API
+
+
+
+https://api.github.com/search/users?q=<email>. Parse the JSON and get the login field of the first item.http-conduit package.
+{-# LANGUAGE OverloadedStrings #-}
+...
+simpleHTTPWithUserAgent :: String -> IO LZ.ByteString
+simpleHTTPWithUserAgent url = do
+ r <- parseUrl url
+ let request = r { requestHeaders = [ ("User-Agent","HTTP-Conduit") ] }
+ withManager $ (return.responseBody) <=< httpLbs request
+
+getGHUser :: String -> IO (Maybe String)
+getGHUser "" = return Nothing
+getGHUser email = do
+ let url = "https://api.github.com/search/users?q=" ++ email
+ body <- simpleHTTPWithUserAgent url
+ ...login=JSON.parse(body).items[0].login. How does Haskell will handle it (knowing the J in JSON is for Javascript)?lens-aeson package and use it that way:
+import Control.Lens.Operators ((^?))
+import Control.Lens.Aeson
+import Data.Aeson.Encode (fromValue)
+import qualified Data.Text.Lazy as TLZ
+import qualified Data.Text.Lazy.Builder as TLB
+
+getGHUser :: String -> IO (Maybe String)
+getGHUser email = do
+ let url = "https://api.github.com/search/users?q=" ++ email
+ body <- simpleHTTPWithUserAgent url
+ let login = body ^? key "items" . nth 0 . key "login"
+ return $ fmap jsonValueToString login
+ where
+ jsonValueToString = TLZ.unpack . TLB.toLazyText . fromValue(^?), key and nth has some great mathematical properties and everything is type safe. Unfortunately I had to make my own jsonValueToString. I hope I simply missed a simpler existing function.lens-aeson and prisms to know more.Concurrency
+
+
+
+zsh script shell. But here is a good occasion to use some Haskell great feature.
+import Control.Concurrent
+...
+main :: IO ()
+main = do
+ intro
+ gitconfig <- safeReadGitConfig
+ let (name,email) = getNameAndMail gitconfig
+ earlyhint <- newEmptyMVar
+ maybe (putMVar earlyhint Nothing) -- if no email found put Nothing
+ (\hintmail -> do -- in the other case request the github API
+ forkIO (putMVar earlyhint =<< getGHUser hintmail)
+ return ())
+ email
+ project <- ask "project name" Nothing
+ ioassert (checkProjectName project)
+ "Use only letters, numbers, spaces and dashes please"
+ let projectname = projectNameFromString project
+ modulename = capitalize project
+ in_author <- ask "name" name
+ in_email <- ask "email" email
+ ghUserHint <- if maybe "" id email /= in_email
+ then getGHUser in_email
+ else takeMVar earlyhint
+ in_ghaccount <- ask "github account" ghUserHint
+ in_synopsis <- ask "project in less than a dozen word?" Nothing
+ current_year <- getCurrentYear
+ createProject $ Project projectname modulename in_author in_email
+ in_ghaccount in_synopsis current_year
+ end
+
+MVar. Mainly a variable which either is empty or contains something.MVar.MVar..gitconfig, you might not even wait.Project Structure
+
+
+.gitconfigModularizing
+
+
+
+src/Main.hs in src/HolyProject.hs. We rename the main function by holyStarter. And our src/Main.hs should contains:src/HolyProject.hs. I separated all functions in different submodules:
+
+HolyProject.GitConfig
+
+
getNameAndMailFromGitConfig: retrieve name an email from .gitconfig fileHolyProject.GithubAPI
+
+
searchGHUser: retrieve github user name using github API.HolyProject.MontyPython
+
+
bk: bridge keeper speaksyou: you speakask: Ask a question and wait for an answerHolyProject.StringUtils: String helper functions
+
+
projectNameFromStringcapitalizecheckProjectNameHolyProject.hs file contains mostly the code that ask questions, show errors and copy files using hastache.Documenting
+
+
+
+-- |. These comment will be used by haddock to create a documentation. First, you need to install haddock manually.haddock in your PATH. You could for example add it like this:dist/doc/html/holy-project/index.html.Tests
+Unit Testing with HUnit
+
+
+
+test/HolyProject/Swallow/Test.hs:
+module HolyProject.Swallow.Test
+ (swallowSuite)
+where
+import Test.Tasty (testGroup, TestTree)
+import Test.Tasty.HUnit
+import HolyProject.Swallow (swallow)
+
+swallowSuite :: TestTree
+swallowSuite = testGroup "Swallow"
+ [testCase "swallow test" testSwallow]
+
+-- in Swallow: swallow = (++)
+testSwallow :: Assertion
+testSwallow = "something" @=? swallow "some" "thing"swallow is (++). We group tests by group. Each group can contain some test suite. Here we have a test suite with only one test. The (@=?) verify the equality between its two parameters.test/HolyProject/Swallow and the file src/HolyProject/Swallow.hs. And we are ready to make our own real world unit test. We will first test the module HolyProject.GithubAPI. Let’s create a file test/HolyProject/GithubAPI/Test.hs with the following content:
+module HolyProject.GithubAPI.Test
+( githubAPISuite
+) where
+import Test.Tasty (testGroup, TestTree)
+import Test.Tasty.HUnit
+import HolyProject.GithubAPI
+
+githubAPISuite :: TestTree
+githubAPISuite = testGroup "GithubAPI"
+ [ testCase "Yann" $ ioTestEq
+ (searchGHUser "Yann.Esposito@gmail.com")
+ (Just "\"yogsototh\"")
+ , testCase "Jasper" $ ioTestEq
+ (searchGHUser "Jasper Van der Jeugt")
+ (Just "\"jaspervdj\"")
+ ]
+
+-- | Test if some IO action returns some expected value
+ioTestEq :: (Eq a, Show a) => IO a -> a -> Assertion
+ioTestEq action expected = action >>= assertEqual "" expectedHolyProject.GithubAPI in the exposed modules of the library secion). You also have to update the test/Test.hs file to use GithubAPI instead of Swallow.Property Testing with SmallCheck and QuickCheck
+
+
+
+StringUtils module.HolyProject.StringUtils in the exposed modules in the library section of your cabal file. Remove all references to the Coconut module.test/Test.hs to remove all references about Coconut. Create a test/HolyProject/StringUtils/Test.hs file containing:
+module HolyProject.StringUtils.Test
+( stringUtilsSuite
+) where
+import Test.Tasty (testGroup, TestTree)
+import Test.Tasty.SmallCheck (forAll)
+import qualified Test.Tasty.SmallCheck as SC
+import qualified Test.Tasty.QuickCheck as QC
+import Test.SmallCheck.Series (Serial)
+import HolyProject.StringUtils
+
+stringUtilsSuite :: TestTree
+stringUtilsSuite = testGroup "StringUtils"
+ [ SC.testProperty "SC projectNameFromString idempotent" $
+ idempotent projectNameFromString
+ , SC.testProperty "SC capitalize idempotent" $
+ deeperIdempotent capitalize
+ , QC.testProperty "QC projectNameFromString idempotent" $
+ idempotent capitalize
+ ]
+
+idempotent f = \s -> f s == f (f s)
+
+deeperIdempotent :: (Eq a, Show a, Serial m a) => (a -> a) -> SC.Property m
+deeperIdempotent f = forAll $ SC.changeDepth1 (+1) $ \s -> f s == f (f s)
+All Tests
+ StringUtils
+ SC projectNameFromString idempotent: OK
+ 206 tests completed
+ SC capitalize idempotent: OK
+ 1237 tests completed
+ QC projectNameFromString idempotent: FAIL
+ *** Failed! Falsifiable (after 19 tests and 5 shrinks):
+ "a a"
+ Use --quickcheck-replay '18 913813783 2147483380' to reproduce.
+ GithubAPI
+ Yann: OK
+ Jasper: OK
+
+1 out of 5 tests failed
+
+capitalize function shouldn’t be idempotent. I simply added this test to show what occurs when a test fail. If you want to look more closely to the error you could do this:
+$ ./interact
+GHCi, version 7.6.2: http://www.haskell.org/ghc/ :? for help
+Loading package ghc-prim ... linking ... done.
+Loading package integer-gmp ... linking ... done.
+Loading package base ... linking ... done.
+Prelude> :l src/HolyProject/StringUtils
+[1 of 1] Compiling HolyProject.StringUtils ( src/HolyProject/StringUtils.hs, interpreted )
+Ok, modules loaded: HolyProject.StringUtils.
+*HolyProject.StringUtils> capitalize "a a"
+"AA"
+*HolyProject.StringUtils> capitalize (capitalize "a a")
+"Aa"
+*HolyProject.StringUtils>./interact instead of ghci. Because we need to tell ghci how to found the package installed.Conclusion
+
+
+
+
+
+
+cabal test.↩name=$(ask name). Simply because $(ask name) run in another process which doesn’t get access to the standard input↩
+
+
+
+
+
+
+
+ Published on 2013-11-14
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/Parsec-Presentation/index.html b/src/Scratch/en/blog/Parsec-Presentation/index.html
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index 0000000..3023c67
--- /dev/null
+++ b/src/Scratch/en/blog/Parsec-Presentation/index.html
@@ -0,0 +1,334 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Learn Vim Progressively
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+1st Level – Survive
+
+
+i.ESC key.
+
+
+
+i → Insert mode. Type ESC to return to Normal mode.x → Delete the char under the cursor:wq → Save and Quit (:w save, :q quit)dd → Delete (and copy) the current linep → Paste
+
+hjkl (highly recommended but not mandatory) → basic cursor move (←↓↑→). Hint: j looks like a down arrow.:help <command> → Show help about <command>. You can use :help without a <command> to get general help.Ctrl key (Ctrl-c generally). In fact, when you press Ctrl, it is as if all of your keys change meaning. Using vim in normal mode is a bit like having the editor automatically press the Ctrl key for you.
+
+Ctrl-λ, I’ll write <C-λ>.: end with <enter>. For example, when I write :q, I mean :q<enter>.2nd Level – Feel comfortable
+
+
+
+
+
+a → insert after the cursoro → insert a new line after the current oneO → insert a new line before the current onecw → replace from the cursor to the end of the word
+
+
+0 → go to the first column^ → go to the first non-blank character of the line$ → go to the end of lineg_ → go to the last non-blank character of line/pattern → search for pattern
+
+
+P → paste before, remember p is paste after current position.yy → copy the current line, easier but equivalent to ddP
+
+
+u → undo<C-r> → redo
+
+
+:e <path/to/file> → open:w → save:saveas <path/to/file> → save to <path/to/file>:x, ZZ or :wq → save and quit (:x only save if necessary):q! → quit without saving, also: :qa! to quit even if there are modified hidden buffers.:bn (resp. :bp) → show next (resp. previous) file (buffer)3rd Level – Better. Stronger. Faster.
+Better
+
+
+. → (dot) will repeat the last command,
+
+
+
+2dd → will delete 2 lines3p → will paste the text 3 times100idesu [ESC] → will write “desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu desu”. → Just after the last command will write again the 100 “desu”.3. → Will write 3 “desu” (and not 300, how clever).Stronger
+
+
+G → Go to line Ngg → shortcut for 1G - go to the start of the fileG → Go to last line
+
+
+w → go to the start of the following word,e → go to the end of this word.
+
+W → go to the start of the following WORD,E → go to the end of this WORD.
+
+
+
+
+
+
+% : Go to the corresponding (, {, [.* (resp. #) : go to next (resp. previous) occurrence of the word under the cursorFaster
+<start position><command><end position>0y$ means
+
+0 → go to the beginning of this liney → yank from here$ → up to the end of this lineye, yank from here to the end of the word. But also y2/foo yank up to the second occurrence of “foo”.y (yank), is also true for d (delete), v (visual select), gU (uppercase), gu (lowercase), etc…4th Level – Vim Superpowers
+Move on current line:
+0 ^ $ g_ f F t T , ;
+
+
+
+0 → go to column 0^ → go to first character on the line$ → go to the last columng_ → go to the last character on the linefa → go to next occurrence of the letter a on the line. , (resp. ;) will find the next (resp. previous) occurrence.t, → go to just before the character ,.3fa → find the 3rd occurrence of a on this line.F and T → like f and t but backward.
+
+
+dt" → remove everything until the ".Zone selection
+<action>a<object> or <action>i<object><action>a<object> and <action>i<object>d (delete), y (yank), v (select in visual mode). The object can be: w a word, W a WORD (extended word), s a sentence, p a paragraph. But also, natural character such as ", ', ), }, ].o of (map (+) ("foo")).
+
+
+
+vi" → will select foo.va" → will select "foo".vi) → will select "foo".va) → will select ("foo").v2i) → will select map (+) ("foo")v2a) → will select (map (+) ("foo"))
+
+
+Select rectangular blocks:
+<C-v>.0<C-v><C-d>I-- [ESC]
+
+^ → go to the first non-blank character of the line<C-v> → Start block selection<C-d> → move down (could also be jjj or %, etc…)I-- [ESC] → write -- to comment each line
+
+
+<C-q> instead of <C-v> if your clipboard is not empty.Completion:
+<C-n> and <C-p>.<C-p>, magic…
+
+
+Macros :
+qa do something q, @a, @@qa record your actions in the register a. Then @a will replay the macro saved into the register a as if you typed it. @@ is a shortcut to replay the last executed macro.
+
+
+
+qaYp<C-a>q →
+
+
qa start recording.Yp duplicate this line.<C-a> increment the number.q stop recording.@a → write 2 under the 1@@ → write 3 under the 2100@@ will create a list of increasing numbers until 103.
+
+
+Visual selection:
+v,V,<C-v><C-v>. There is also v and V. Once the selection has been made, you can:
+
+J → join all the lines together.< (resp. >) → indent to the left (resp. to the right).= → auto indent
+
+
+
+
+<C-v>jjj or <C-d> or /pattern or % etc…)$ go to the end of the lineA, write text, ESC.
+
+
+Splits:
+:split and vsplit.:help split.
+
+
+
+:split → create a split (:vsplit create a vertical split)<C-w><dir> : where dir is any of hjkl or ←↓↑→ to change the split.<C-w>_ (resp. <C-w>|) : maximise the size of the split (resp. vertical split)<C-w>+ (resp. <C-w>-) : Grow (resp. shrink) split
+
+
+Conclusion
+:help usr_02.txt.!, folds, registers, plugins and many other features. Learn vim like you’d learn piano and all should be fine.
+
+
+
+
+
+
+
+
+
+
+ Published on 2011-08-25
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/Password-Management/index.html b/src/Scratch/en/blog/Password-Management/index.html
new file mode 100644
index 0000000..66947b4
--- /dev/null
+++ b/src/Scratch/en/blog/Password-Management/index.html
@@ -0,0 +1,170 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Parsec Presentation
+
+
+
+
+
+
+ 
+
+
+
+
+
+
+
+
+
+
+
+Parsing Example
+
+
+(1+3)*(1+5+9)
+
+
+
+
+
+
+
+
+ Published on 2013-10-09
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/Rational-Web-Framework-Choice/index.html b/src/Scratch/en/blog/Rational-Web-Framework-Choice/index.html
new file mode 100644
index 0000000..a541851
--- /dev/null
+++ b/src/Scratch/en/blog/Rational-Web-Framework-Choice/index.html
@@ -0,0 +1,2296 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ 40 character's passwords
+
+
+
+
+
+
+
+
+
+
+
+
+sha1( password + domain_name )
+I memorize only one password. I use a different password on all website.Why you should use a Password Manager?
+
+
+Which methodology?
+
+
+
+
+P45sW0r|)TwitterP45sW0r|)gmailP45sW0r|)badonlinegame9f00fd5dbba232b7c03afd2b62b5fce5cdc7df63, he will have hard time to recover P45sW0r|). sha1( master_password + domain_name ) ~~~~~~
+
+master_password is your unique master password,domain_name is the domain name of the website you want the password for,
+
+
+In practice?
+
+
+
+
+
+
+
+
+
+
+
+
+ Published on 2011-05-18
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/SVG-and-m4-fractals/code/yesodlogo.m4 b/src/Scratch/en/blog/SVG-and-m4-fractals/code/yesodlogo.m4
new file mode 100644
index 0000000..39ab18c
--- /dev/null
+++ b/src/Scratch/en/blog/SVG-and-m4-fractals/code/yesodlogo.m4
@@ -0,0 +1,43 @@
+
+
+
diff --git a/src/Scratch/en/blog/SVG-and-m4-fractals/index.html b/src/Scratch/en/blog/SVG-and-m4-fractals/index.html
new file mode 100644
index 0000000..86b33f1
--- /dev/null
+++ b/src/Scratch/en/blog/SVG-and-m4-fractals/index.html
@@ -0,0 +1,237 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Rational Web Framework Choice
+
+
+
+
+
+
+
+
+
+
+
+
+You’ve got the next big idea.
+You just need to make a very simple web application.![[Choice Paralysis][choice_paralysis]](../../../../Scratch/img/blog/Rational-Web-Framework-Choice/choice_paralysis.gif)
+
+What is the most popular web framework for this language?
+
+
+you hadn’t made the best either.”
+
+
+
+
+
+I am far from happy to the actual result. There are a lot of biases, for example in the choice of the parameters. The same can be said about the data I gathered. I am using very imprecise informations. But, as far as I know, this is the only article which use many different parameters to help you choose a web framework.Model
+
+
+
+
+
+
+
+score(framework) = efficiency + robustness + expressiveness + popularity
+
+
+
+
+
+
+Expressiveness
+10
+7
+1
+-∞
+-∞
+-∞
+
+
+Popularity
+5
+5
+4
+3
+2
+1
+
+
+Efficiency
+10
+8
+6
+4
+2
+1
+
+
+
+Robustness
+10
+8
+6
+4
+2
+1
+
+
+
+
+
+
+
+
+
+
+ Expressiveness
+Popularity
+Efficiency
+Robustness
+
+
+
+yog
+Excellent
+Very Bad
+Medium
+Very Good
+
+score(yog) = 10 + 0 + 4 + 8 = 22Objective measures
+Popularity
+![Mainstream Languages Cluster from [RedMonk][redmonk]](../../../../Scratch/img/blog/Rational-Web-Framework-Choice/mainstreamlanguages.png)
+![Second tier languages from [RedMonk][redmonk]](../../../../Scratch/img/blog/Rational-Web-Framework-Choice/secondtierlanguages.png)
+C#, C++, C, Objective-C, Perl, Shell
+
+
+
+
+
+
+Cluster
+Language
+Framework
+#nb
+%
+
+
+Excellent
+Ruby
+Rails
+176208
+100%
+
+
+Very Good
+Python
+Django
+57385
+<50%
+
+
+
+ Java
+Servlet
+54139
+
+
+
+
+ Java
+Spring
+31641
+
+
+
+
+ Node.js
+node.js
+27243
+
+
+
+
+ PHP
+Codeigniter
+21503
+
+
+
+
+ Groovy
+Grails
+20222
+
+
+
+Good
+Ruby
+Sinatra
+8631
+<25%
+
+
+
+ Python
+Flask
+7062
+
+
+
+
+ PHP
+Laravel
+6982
+
+
+
+
+ PHP
+Kohana
+5959
+
+
+
+
+ Node.js
+Express
+5009
+
+
+
+Medium
+PHP
+Cake
+4554
+<13%
+
+
+
+ C♯
+ServiceStack
+3838
+
+
+
+
+ Scala
+Play
+3823
+
+
+
+
+ Java
+Wicket
+3819
+
+
+
+
+ Dart
+Dart
+3753
+
+
+
+
+ PHP
+Slim
+3361
+
+
+
+
+ Python
+Tornado
+3321
+
+
+
+
+ Scala
+Lift
+2844
+
+
+
+
+ Go
+Go
+2689
+
+
+
+Bad
+Java
+Tapestry
+1197
+<6%
+
+
+
+ C♯
+aspnet
+1000
+
+
+
+
+ Haskell
+Yesod
+889
+
+
+
+
+ PHP
+Silex
+750
+
+
+
+
+ PHP
+Lithium
+732
+
+
+
+
+ C♯
+nancy
+705
+
+
+
+Very bad
+Java
+Grizzly
+622
+<3%
+
+
+
+ Erlang
+Cowboy
+568
+
+
+
+
+ Perl
+Dancer
+496
+
+
+
+
+ PHP
+Symphony2
+491
+
+
+
+
+ Go
+Revel
+459
+
+
+
+
+ Clojure
+Compojure
+391
+
+
+
+
+ Perl
+Mojolicious
+376
+
+
+
+
+ Scala
+Scalatra
+349
+
+
+
+
+ Scala
+Finagle
+336
+
+
+
+
+ PHP
+Phalcon
+299
+
+
+
+
+ js
+Ringo
+299
+
+
+
+
+ Java
+Gemini
+276
+
+
+
+
+ Haskell
+Snap
+263
+
+
+
+
+ Perl
+Plack
+257
+
+
+
+
+ Erlang
+Elli
+230
+
+
+
+
+ Java
+Dropwizard
+188
+
+
+
+
+ PHP
+Yaf
+146
+
+
+
+
+ Java
+Play1
+133
+
+
+
+
+ Node.js
+Hapi
+131
+
+
+
+
+ Java
+Vertx
+60
+
+
+
+
+ Scala
+Unfiltered
+42
+
+
+
+
+ C
+onion
+18
+
+
+
+
+ Clojure
+http-kit
+17
+
+
+
+
+ Perl
+Kelp
+16
+
+
+
+
+ PHP
+Micromvc
+13
+
+
+
+
+ Lua
+Openresty
+8
+
+
+
+
+ C++
+cpoll-cppsp
+5
+
+
+
+
+ Clojure
+Luminus
+3
+
+
+
+
+
+ PHP
+Phreeze
+1
+
+ Efficiency
+
+
+
+
+
+1x→2x
+C, C++
+
+2x→3x
+Java 7, Scala, OCamL, Haskell, Go, Common LISP
+
+
+3x→10x
+C♯, Clojure, Racket, Dart
+
+
+10x→30x
+Erlang
+
+
+
+30x→
+PHP, Python, Perl, Ruby, JRuby
+
+
+
+
+
+
+
+
+
+Cluster
+Language
+Framework
+#nb
+slowness
+
+
+Excellent
+C++
+cpoll-cppsp
+114,711
+1×
+
+
+
+ Jav
+gemini
+105,204
+
+
+
+
+ Lua
+openresty
+93,882
+
+
+
+
+ Jav
+servlet
+90,580
+
+
+
+
+ C++
+cpoll-pool
+89,167
+
+
+
+
+ Go
+go
+76,024
+
+
+
+
+ Sca
+finagle
+68,413
+
+
+
+
+ Go
+revel
+66,990
+
+
+
+
+ Jav
+rest-express
+63,209
+
+
+
+Very Good
+Jav
+wicket
+48,772
+>2×
+
+
+
+ Sca
+scalatra
+48,594
+
+
+
+
+ Clj
+http-kit
+42,703
+
+
+
+
+ Jav
+spring
+36,643
+>3×
+
+
+
+ PHP
+php
+36,605
+
+
+
+
+ Jav
+tapestry
+35,032
+
+
+
+
+ Clj
+compojure
+32,088
+
+
+
+
+ JS
+ringo
+31,962
+
+
+
+
+ Jav
+dropwizard
+31,514
+
+
+
+
+ Clj
+luminus
+30,672
+
+
+
+Good
+Sca
+play-slick
+29,950
+>4×
+
+
+
+ Sca
+unfiltered
+29,782
+
+
+
+
+ Erl
+elli
+28,862
+
+
+
+
+ Jav
+vertx
+28,075
+
+
+
+
+ JS
+nodejs
+27,598
+
+
+
+
+ Erl
+cowboy
+24,669
+
+
+
+
+ C
+onion
+23,649
+
+
+
+
+ Hkl
+yesod
+23,304
+
+
+
+
+ JS
+express
+22,856
+>5×
+
+
+
+ Sca
+play-scala
+22,372
+
+
+
+
+ Jav g
+rizzly-jersey
+20,550
+
+
+
+
+ Py
+tornado
+20,372
+>6×
+
+
+
+ PHP
+phalcon
+18,481
+
+
+
+
+ Grv
+grails
+18,467
+
+
+
+
+ Prl
+plack
+16,647
+>7×
+
+
+
+ PHP
+yaf
+14,388
+
+
+
+Medium
+JS
+hapi
+11,235
+>10×
+
+
+
+ Jav
+play1
+9,979
+
+
+
+
+ Hkl
+snap
+9,196
+
+
+
+
+ Prl
+kelp
+8,250
+
+
+
+
+ Py
+flask
+8,167
+
+
+
+
+ Jav
+play-java
+7,905
+
+
+
+
+ Jav p
+lay-java-jpa
+7,846
+
+
+
+
+ PHP
+micromvc
+7,387
+
+
+
+
+ Prl
+dancer
+5,040
+>20×
+
+
+
+ Prl
+mojolicious
+4,371
+
+
+
+
+ JS
+ringo-conv
+4,249
+
+
+
+
+ Py
+django
+4,026
+
+
+
+
+ PHP
+codeigniter
+3,809
+>30×
+
+
+Bad
+Rby
+rails
+3,445
+
+
+
+
+ Sca
+lift
+3,311
+
+
+
+
+ PHP
+slim
+3,112
+
+
+
+
+ PHP
+kohana
+2,378
+>40×
+
+
+
+ PHP
+silex
+2,364
+
+
+
+Very Bad
+PHP
+laravel
+1,639
+>60×
+
+
+
+ PHP
+phreeze
+1,410
+
+
+
+
+ PHP
+lithium
+1,410
+
+
+
+
+ PHP
+fuel
+1,410
+
+
+
+
+ PHP
+cake
+1,287
+>80×
+
+
+
+ PHP
+symfony2
+879
+>100×
+
+
+
+ C#
+aspnet-mvc
+871
+
+
+
+
+ Rby
+sinatra
+561
+>200×
+
+
+
+ C#
+servicestack
+51
+
+
+
+
+ Dar
+dart
+0
+
+
+
+
+ C#
+nancy
+0
+
+
+
+
+
+ Prl
+web-simple
+0
+
+ Expressiveness
+
+
+
+
+
+
+
+Cluster
+Languages
+
+
+Excellent
+Coffeescript, Clojure, Haskell
+
+
+Very Good
+Racket, Groovy, R, Scala, OCamL, F♯, Erlang, Lisp, Go
+
+
+Medium
+Perl, Python, Objective-C, Scheme, Tcl, Ruby
+
+
+Bad
+Lua, Fortran (free-format), PHP, Java, C++, C♯
+
+
+
+Very Bad
+Assembly, C, Javascript,
+
+Click here to show/hide the table for frameworks
+
+
+
+
+
+
+
+
+
+
+Cluster
+Language
+Framework
+
+
+Excellent
+Clj
+luminus
+
+
+
+ Clj
+http-kit
+
+
+
+ Clj
+compojure
+
+
+
+ Hkl
+snap
+
+
+
+ Hkl
+yesod
+
+
+Very Good
+Erl
+elli
+
+
+
+ Erl
+cowboy
+
+
+
+ Go
+go
+
+
+
+ Go
+revel
+
+
+
+ Grv
+grails
+
+
+
+ Sca
+lift
+
+
+
+ Sca
+finagle
+
+
+
+ Sca
+scalatra
+
+
+
+ Sca
+play-scala
+
+
+
+ Sca
+play-slick
+
+
+
+ Sca
+unfiltered
+
+
+Medium
+Prl
+kelp
+
+
+
+ Prl
+plack
+
+
+
+ Prl
+dancer
+
+
+
+ Prl
+web-simple
+
+
+
+ Prl
+mojolicious
+
+
+
+ Py
+flask
+
+
+
+ Py
+django
+
+
+
+ Py
+tornado
+
+
+
+ Rby
+rails
+
+
+
+ Rby
+sinatra
+
+
+Bad
+C#
+nancy
+
+
+
+ C#
+aspnet-mvc
+
+
+
+ C#
+servicestack
+
+
+
+ C++
+cpoll-pool
+
+
+
+ C++
+cpoll-cppsp
+
+
+
+ Dar
+dart
+
+
+
+ Jav
+play1
+
+
+
+ Jav
+vertx
+
+
+
+ Jav
+gemini
+
+
+
+ Jav
+spring
+
+
+
+ Jav
+wicket
+
+
+
+ Jav
+servlet
+
+
+
+ Jav
+tapestry
+
+
+
+ Jav
+play-java
+
+
+
+ Jav
+dropwizard
+
+
+
+ Jav
+rest-express
+
+
+
+ Jav
+play-java-jpa
+
+
+
+ Jav
+grizzly-jersey
+
+
+
+ Lua
+openresty
+
+
+
+ PHP
+php
+
+
+
+ PHP
+yaf
+
+
+
+ PHP
+cake
+
+
+
+ PHP
+fuel
+
+
+
+ PHP
+slim
+
+
+
+ PHP
+silex
+
+
+
+ PHP
+kohana
+
+
+
+ PHP
+laravel
+
+
+
+ PHP
+lithium
+
+
+
+ PHP
+phalcon
+
+
+
+ PHP
+phreeze
+
+
+
+ PHP
+micromvc
+
+
+
+ PHP
+symfony2
+
+
+
+ PHP
+codeigniter
+
+
+Very Bad
+C
+onion
+
+
+
+ JS
+hapi
+
+
+
+ JS
+ringo
+
+
+
+ JS
+nodejs
+
+
+
+ JS
+express
+
+
+
+
+ JS
+ringo-conv
+Robustness
+![Static Type Properties from [James IRY Blog][typesanalysis]](../../../../Scratch/img/blog/Rational-Web-Framework-Choice/languagesafety.png)
+
+
+
+
+
+Excellent
+Haskell, Scheme, Erlang
+
+
+Very Good
+Scala, Java, Clojure
+
+
+Good
+Ruby, Python, Groovy, javascript, PHP
+
+
+
+Medium
+C++, C#, Perl, Objective-C, Go, C
+
+Click here to show/hide the table for frameworks
+
+
+
+
+
+
+
+
+
+
+Cluster
+Language
+Framework
+
+
+Excellent
+Erl
+elli
+
+
+
+ Erl
+cowboy
+
+
+
+ Hkl
+snap
+
+
+
+ Hkl
+yesod
+
+
+Very Good
+Clj
+luminus
+
+
+
+ Clj
+http-kit
+
+
+
+ Clj
+compojure
+
+
+
+ Jav
+play1
+
+
+
+ Jav
+vertx
+
+
+
+ Jav
+gemini
+
+
+
+ Jav
+spring
+
+
+
+ Jav
+wicket
+
+
+
+ Jav
+servlet
+
+
+
+ Jav
+tapestry
+
+
+
+ Jav
+play-java
+
+
+
+ Jav
+dropwizard
+
+
+
+ Jav
+rest-express
+
+
+
+ Jav
+play-java-jpa
+
+
+
+ Jav
+grizzly-jersey
+
+
+
+ Sca
+lift
+
+
+
+ Sca
+finagle
+
+
+
+ Sca
+scalatra
+
+
+
+ Sca
+play-scala
+
+
+
+ Sca
+play-slick
+
+
+
+ Sca
+unfiltered
+
+
+Good
+Grv
+grails
+
+
+
+ JS
+hapi
+
+
+
+ JS
+ringo
+
+
+
+ JS
+nodejs
+
+
+
+ JS
+express
+
+
+
+ JS
+ringo-conv
+
+
+
+ Lua
+openresty
+
+
+
+ PHP
+php
+
+
+
+ PHP
+yaf
+
+
+
+ PHP
+cake
+
+
+
+ PHP
+fuel
+
+
+
+ PHP
+slim
+
+
+
+ PHP
+silex
+
+
+
+ PHP
+kohana
+
+
+
+ PHP
+laravel
+
+
+
+ PHP
+lithium
+
+
+
+ PHP
+phalcon
+
+
+
+ PHP
+phreeze
+
+
+
+ PHP
+micromvc
+
+
+
+ PHP
+symfony2
+
+
+
+ PHP
+codeigniter
+
+
+
+ Py
+flask
+
+
+
+ Py
+django
+
+
+
+ Py
+tornado
+
+
+
+ Rby
+rails
+
+
+
+ Rby
+sinatra
+
+
+Medium
+C
+onion
+
+
+
+ C#
+nancy
+
+
+
+ C#
+aspnet-mvc
+
+
+
+ C#
+servicestack
+
+
+
+ C++
+cpoll-pool
+
+
+
+ C++
+cpoll-cppsp
+
+
+
+ Dar
+dart
+
+
+
+ Go
+go
+
+
+
+ Go
+revel
+
+
+
+ Prl
+kelp
+
+
+
+ Prl
+plack
+
+
+
+ Prl
+dancer
+
+
+
+ Prl
+web-simple
+
+
+
+
+ Prl
+mojolicious
+The result
+
+
+
+
+
+
+
+Excellent
+
+
+Very good
+
+
+Good
+
+
+Medium
+
+
+Bad
+
+
+Very bad
+
+
+Importance
+
+
+
+
+Expressiveness
+
+
+
+
+Popularity
+
+
+
+
+Efficiency
+
+
+
+
+Robustness
+
+
+Click to force refresh
+
+
+
+
+
+
+Conclusion
+
+
+
+
+
+
+
+
+ Published on 2013-08-06
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/Safer-Haskell-Install/index.html b/src/Scratch/en/blog/Safer-Haskell-Install/index.html
new file mode 100644
index 0000000..55a7170
--- /dev/null
+++ b/src/Scratch/en/blog/Safer-Haskell-Install/index.html
@@ -0,0 +1,151 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Increase the power of deficient languages.
+ Fractals with SVG and m4
+
+
+
+
+
+
+
+
+
+
+
+The xslt Example
+m4. Yes, the preprocessor you use when you program in C and C++.
+
+
+myvar = value, here is the
+
+
+print "Hello world!" here is the
+
+
+print myvar the
+
+The cure (m4 to the rescue)
+
+<?xml version="1.0" standalone="yes"?> <!-- YES its <span class="sc">xml</span> -->
+<!-- ← start a comment, then write some m4 directives:
+
+define(`ydef',`<xsl:variable name="$1" select="$2"/>')
+define(`yprint',`<xsl:text disable-output-escaping="yes"><![CDATA[$1]]></xsl:text>')
+define(`yshow',`<xsl:value-of select="$1"/>')
+
+-->
+<!-- Yes, <span class="sc">xml</span> sucks to be read -->
+<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
+<!-- And it sucks even more to edit -->
+<xsl:template match="/">
+ ydef(myvar,value)
+ yprint(Hello world!)
+ yshow(myvar)
+</xsl:template>The cool part: Fractals!
+
+
+
+
+
+
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!--
+ M4 Macros
+define(`YTRANSFORMONE', `scale(.43) translate(-120,-69) rotate(-10)')
+define(`YTRANSFORMTWO', `scale(.43) translate(-9,-67.5) rotate(10)')
+define(`YTRANSFORMTHREE', `scale(.43) translate(53,41) rotate(120)')
+define(`YGENTRANSFORM', `translate(364,274) scale(3)')
+define(`YTRANSCOMPLETE', `
+ <g id="level_$1">
+ <use style="opacity: .8" transform="YTRANSFORMONE" xlink:href="#level_$2" />
+ <use style="opacity: .8" transform="YTRANSFORMTWO" xlink:href="#level_$2" />
+ <use style="opacity: .8" transform="YTRANSFORMTHREE" xlink:href="#level_$2" />
+ </g>
+ <use transform="YGENTRANSFORM" xlink:href="#level_$1" />
+')
+ -->
+<svg
+ xmlns="http://www.w3.org/2000/svg"
+ xmlns:xlink="http://www.w3.org/1999/xlink"
+ x="64" y="64" width="512" height="512" viewBox="64 64 512 512"
+ id="svg2" version="1.1">
+ <g id="level_0"> <!-- some group, if I want to add other elements -->
+ <!-- the text "λ" -->
+ <text id="lambda"
+ fill="#333" style="font-family:Ubuntu; font-size: 100px"
+ transform="rotate(180)">λ</text>
+ </g>
+ <!-- the text "esod" -->
+ <text
+ fill="#333"
+ style="font-family:Ubuntu; font-size: 28px; letter-spacing: -0.10em"
+ x="-17.3"
+ y="69"
+ transform="YGENTRANSFORM">esod</text>
+ <!-- ROOT ELEMENT -->
+ <use transform="YGENTRANSFORM" xlink:href="#level_0" />
+
+ YTRANSCOMPLETE(1,0) <!-- First recursion -->
+ YTRANSCOMPLETE(2,1) <!-- deeper -->
+ YTRANSCOMPLETE(3,2) <!-- deeper -->
+ YTRANSCOMPLETE(4,3) <!-- even deeper -->
+ YTRANSCOMPLETE(5,4) <!-- Five level seems enough -->
+</svg>YTRANSFORMONE, YTRANSFORMTWO and YTRANSFORMTHREE.YTRANSCOMPLETE. This macro takes two arguments. The current depth and the preceding one. It duplicates using the three transformations the preceding level.
+
+Conclusion
+
+
+
+
+
+
+
+
+ Published on 2011-10-20
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/Social-link-the-right-way/index.html b/src/Scratch/en/blog/Social-link-the-right-way/index.html
new file mode 100644
index 0000000..5358b7d
--- /dev/null
+++ b/src/Scratch/en/blog/Social-link-the-right-way/index.html
@@ -0,0 +1,300 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Safer Haskell Install
+
+
+
+
+
+
+
+
+
+
+
+
+curl https://raw.githubusercontent.com/yogsototh/install-haskell/master/install-haskell.sh | sudo zshWhy?
+
+
+
+curl https://raw.githubusercontent.com/yogsototh/install-haskell/master/install-haskell.sh | sudo zshHow?
+
+
+GHC binary for you system and install it.cabal program.~/.cabal directory.Some Last Words
+nix. Unfortunately, sandboxes didn’t worked good enough for me after some time. Furthermore, sandboxes forces you to re-compile everything by project. If you have three yesod projects for example it means a lot of time and CPU. Also, nix didn’t worked as expected on OS X. So fixing the list of package to a stable list of them seems to me the best pragmatic way to handle the problem today.
+
+
+
+
+
+
+
+
+
+
+
+ Published on 2014-08-16
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/Typography-and-the-Web/index.html b/src/Scratch/en/blog/Typography-and-the-Web/index.html
new file mode 100644
index 0000000..5341036
--- /dev/null
+++ b/src/Scratch/en/blog/Typography-and-the-Web/index.html
@@ -0,0 +1,165 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Social link the right way
+
+
+
+
+
+
+
+
+
+
+
+
+<div id="sociallinks">
+ <a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Tweet this</a> -
+ <a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Like this</a> -
+ <a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Share on G+</a>
+</div>
+<script>
+(function(){window.addEventListener("DOMContentLoaded",function(){
+ var url=document.location;
+ var links=document.getElementById("sociallinks")
+ .getElementsByTagName('a');
+ for (var i=0;i!=links.length;i++){
+ links[i].setAttribute("href",
+ links[i].href.replace('$url$',url));}})})();
+</script>The problem
+document.write in their js you call asynchronously and BAM! Your website is just an empty blank page. And as you call many external ressources, it can be very difficult to find the origin of the problem.
+
+
+
+
Solutions
+
+
+
+
+
+<a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Tweet this</a>
+
+<a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Like this</a>
+
+<a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Share on G+</a>$url$ by the current url.
+<div id="sociallinks">
+ <a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Tweet this</a> -
+ <a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Like this</a> -
+ <a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Share on G+</a>
+</div>
+<script>
+(function(){window.addEventListener("DOMContentLoaded",function(){
+ var url=document.location;
+ var links=document.getElementById("sociallinks")
+ .getElementsByTagName('a');
+ for (var i=0;i!=links.length;i++){
+ links[i].setAttribute("href",
+ links[i].href.replace('$url$',url));}})})();
+</script>
+
+
+
+Good looking solutions
+
+
+<img src="..."/> in the links.
+
+
+@font-face
+ font-family: 'social'
+ src: url('fonts/social_font.ttf') format('truetype')
+ font-weight: normal
+ font-style: normal
+.social
+ font-family: social
+<a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">t</a>
+·
+<a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">`</a>
+·
+<a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">g</a>
+<div id="sociallinksunicode">
+<a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">t</a>
+·
+<a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">`</a>
+·
+<a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">g</a>
+</div>
+<script>
+(function(){window.addEventListener("DOMContentLoaded",function(){
+ var url=document.location;
+ var links=document.getElementById("sociallinksunicode")
+ .getElementsByTagName('a');
+ for (var i=0;i!=links.length;i++){
+ links[i].setAttribute("href",
+ links[i].href.replace('$url$',url));}})})();
+</script>
+
+
+
+Conclusion
+
+
+
+
+
+
+
+
+
+
+ Published on 2013-03-14
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/Vim-as-IDE/index.html b/src/Scratch/en/blog/Vim-as-IDE/index.html
new file mode 100644
index 0000000..7710650
--- /dev/null
+++ b/src/Scratch/en/blog/Vim-as-IDE/index.html
@@ -0,0 +1,333 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Typography and the Web
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+text-rendering: optimizelegibility. But it also works because I use the right font; Computer Modern. Steal my CSS at will.↩
+
+
+
+
+
+
+
+ Published on 2012-02-02
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/Yesod-excellent-ideas/index.html b/src/Scratch/en/blog/Yesod-excellent-ideas/index.html
new file mode 100644
index 0000000..84a00f9
--- /dev/null
+++ b/src/Scratch/en/blog/Yesod-excellent-ideas/index.html
@@ -0,0 +1,177 @@
+
+
+
+
+
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Vim as IDE
+
+
+
+
+
+
+
+
+
+
+
+Vim Plugin Manager
+vim-plug.
+mkdir -p ~/.vim/autoload
+curl -fLo ~/.vim/autoload/plug.vim \
+ https://raw.githubusercontent.com/junegunn/vim-plug/master/plug.vim
+
+.vimrc. The first part contains the list of all my plugins. The second part contains the personal preferences I setted for each plugin. I’ll separate each part by ... in the code.Survival
+Colorscheme
+
+
+
+~/.vimrc file:
+call plug#begin('~/.vim/plugged')
+
+Plug 'altercation/vim-colors-solarized'
+
+call plug#end()
+
+" -- solarized personal conf
+set background=dark
+try
+ colorscheme solarized
+catch
+endtryMinimal hygiene
+
+
+
+
+Plug 'bronson/vim-trailing-whitespace':FixWhitespace.
+if (exists('+colorcolumn'))
+ set colorcolumn=80
+ highlight ColorColumn ctermbg=9
+endif
+
+
+File Management
+NERDTree. This is the classical left column with a tree of files of your project. I stopped to use this. And you should probably too.ag (the silver search). If you don’t know ack or ag your life is going to be upgraded. This is a simple but essential tool. It is mostly a grep on steroids.
+" Unite
+" depend on vimproc
+" ------------- VERY IMPORTANT ------------
+" you have to go to .vim/plugin/vimproc.vim and do a ./make
+" -----------------------------------------
+Plug 'Shougo/vimproc.vim'
+Plug 'Shougo/unite.vim'
+
+...
+
+let g:unite_source_history_yank_enable = 1
+try
+ let g:unite_source_rec_async_command='ag --nocolor --nogroup -g ""'
+ call unite#filters#matcher_default#use(['matcher_fuzzy'])
+catch
+endtry
+" search a file in the filetree
+nnoremap <space><space> :split<cr> :<C-u>Unite -start-insert file_rec/async<cr>
+" reset not it is <C-l> normally
+:nnoremap <space>r <Plug>(unite_restart)
+
+
+<space>r to reset the unite cache.ag:
+Plug 'rking/ag.vim'
+...
+" --- type ° to search the word in all files in the current dir
+nmap ° :Ag <c-r>=expand("<cword>")<cr><cr>
+nnoremap <space>/ :Ag:Ag.° which is nicely positioned on my azerty keyboard. You should use a key close to *.° is doing? It reads the string under the cursor and search for it in all files. Really useful to search where a function is used.<space>/ followed by a string, it will search for all occurrences of this string in the project files.Language Agnostic Plugins
+Git
+
+
+
+
+Plug 'airblade/vim-gitgutter'
+Plug 'tpope/vim-fugitive':Gread. You can stage your changes with :Gwrite.
+
+
+Align things
+
+Plug 'junegunn/vim-easy-align'
+
+...
+
+" Easy align interactive
+vnoremap <silent> <Enter> :EasyAlign<cr>Return then space. Type Return many type to change the alignments.Return then 2 then space.
+
+
+Basic auto completion:
+C-n & C-pC-n and C-p while you are in insert mode. This is generally good enough in most cases. For example when I open a file not in my configured languages.Haskell
+
+
+ghc-mod with: cabal install ghc-mod
+" ---------- VERY IMPORTANT -----------
+" Don't forget to install ghc-mod with:
+" cabal install ghc-mod
+" -------------------------------------
+
+Plug 'scrooloose/syntastic' " syntax checker
+" --- Haskell
+Plug 'yogsototh/haskell-vim' " syntax indentation / highlight
+Plug 'enomsg/vim-haskellConcealPlus' " unicode for haskell operators
+Plug 'eagletmt/ghcmod-vim'
+Plug 'eagletmt/neco-ghc'
+Plug 'Twinside/vim-hoogle'
+Plug 'pbrisbin/html-template-syntax' " Yesod templates
+
+...
+
+" -------------------
+" Haskell
+" -------------------
+let mapleader="-"
+let g:mapleader="-"
+set tm=2000
+nmap <silent> <leader>ht :GhcModType<CR>
+nmap <silent> <leader>hh :GhcModTypeClear<CR>
+nmap <silent> <leader>hT :GhcModTypeInsert<CR>
+nmap <silent> <leader>hc :SyntasticCheck ghc_mod<CR>:lopen<CR>
+let g:syntastic_mode_map={'mode': 'active', 'passive_filetypes': ['haskell']}
+let g:syntastic_always_populate_loc_list = 1
+nmap <silent> <leader>hl :SyntasticCheck hlint<CR>:lopen<CR>
+
+" Auto-checking on writing
+autocmd BufWritePost *.hs,*.lhs GhcModCheckAndLintAsync
+
+" neocomplcache (advanced completion)
+autocmd BufEnter *.hs,*.lhs let g:neocomplcache_enable_at_startup = 1
+function! SetToCabalBuild()
+ if glob("*.cabal") != ''
+ set makeprg=cabal\ build
+ endif
+endfunction
+autocmd BufEnter *.hs,*.lhs :call SetToCabalBuild()
+
+" -- neco-ghc
+let $PATH=$PATH.':'.expand("~/.cabal/bin")
+
+
+- for my leader because I use , a lot for its native usage.
+
+-ht will highlight and show the type of the block under the cursor.-hT will insert the type of the current block.-hh will unhighlight the selection.
+
+
+Clojure
+
+
+
+lein-kibit thought. If I have the courage I might do it myself one day. But due to the very long startup time of clojure, I doubt I’ll be able to make a useful vim plugin.paredit plugin before. But it is too restrictive. Now I use sexp which feel more coherent with the spirit of vim.
+" " -- Clojure
+Plug 'kien/rainbow_parentheses.vim'
+Plug 'guns/vim-clojure-static'
+Plug 'guns/vim-sexp'
+Plug 'tpope/vim-repeat'
+Plug 'tpope/vim-fireplace'
+
+...
+
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl RainbowParenthesesActivate
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl RainbowParenthesesLoadRound
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl RainbowParenthesesLoadSquare
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl RainbowParenthesesLoadBraces
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl setlocal iskeyword+=?,-,*,!,+,/,=,<,>,.,:
+" -- Rainbow parenthesis options
+let g:rbpt_colorpairs = [
+ \ ['darkyellow', 'RoyalBlue3'],
+ \ ['darkgreen', 'SeaGreen3'],
+ \ ['darkcyan', 'DarkOrchid3'],
+ \ ['Darkblue', 'firebrick3'],
+ \ ['DarkMagenta', 'RoyalBlue3'],
+ \ ['darkred', 'SeaGreen3'],
+ \ ['darkyellow', 'DarkOrchid3'],
+ \ ['darkgreen', 'firebrick3'],
+ \ ['darkcyan', 'RoyalBlue3'],
+ \ ['Darkblue', 'SeaGreen3'],
+ \ ['DarkMagenta', 'DarkOrchid3'],
+ \ ['Darkblue', 'firebrick3'],
+ \ ['darkcyan', 'SeaGreen3'],
+ \ ['darkgreen', 'RoyalBlue3'],
+ \ ['darkyellow', 'DarkOrchid3'],
+ \ ['darkred', 'firebrick3'],
+ \ ]Last words
+
+
+
+
+
+
+
+
+ Published on 2014-12-07
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
+
+
diff --git a/src/Scratch/en/blog/Yesod-tutorial-for-newbies/code/Echo.hs b/src/Scratch/en/blog/Yesod-tutorial-for-newbies/code/Echo.hs
new file mode 100644
index 0000000..4ba6b60
--- /dev/null
+++ b/src/Scratch/en/blog/Yesod-tutorial-for-newbies/code/Echo.hs
@@ -0,0 +1,8 @@
+module Handler.Echo where
+
+import Import
+
+getEchoR :: Text -> Handler RepHtml
+getEchoR theText = do
+ defaultLayout $ do
+ [whamlet|
+
+
+
+
+ French
+
+
+
+
+
+
+
+ Yesod excellent ideas
+
+
+
+
+
+
+
+
+
+
+
+Type safety
+
< into <. Without this transformation alert will appear each time you try to display this user name. Safe types associate with each string what kind of string it is. Is it a string for URL? For javascript? For HTML? And the right protection is made by default to prevent problems.AnotherPageR is of type URL and it could not contains something nefarious. It will be an URL safe. Not something like:Widgets
+
+
+
+
+
+htmlheader = ...
+cssheader = ...
+javascriptheader = ...
+htmlbody = ...
+toWidgetHeader cassiusFile "button.cassius"
+toWidgetHeader juliusFile "button.julius"
+toWidget hamletFile "buttonTemplate.hamlet"
+
+Optimized routing
+date = 2003 inside the handler.Why yesod?
+
+
+
+
+
+
+
+
+
+
+ Published on 2011-10-04
+
+
+
+ Yann Esposito©
+
+
+
+
+
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ #{theText}|]
diff --git a/src/Scratch/en/blog/Yesod-tutorial-for-newbies/code/Mirror.hs b/src/Scratch/en/blog/Yesod-tutorial-for-newbies/code/Mirror.hs
new file mode 100644
index 0000000..c7a006a
--- /dev/null
+++ b/src/Scratch/en/blog/Yesod-tutorial-for-newbies/code/Mirror.hs
@@ -0,0 +1,15 @@
+module Handler.Mirror where
+
+import Import
+import qualified Data.Text as T
+
+getMirrorR :: Handler RepHtml
+getMirrorR = do
+ defaultLayout $ do
+ $(widgetFile "mirror")
+
+postMirrorR :: Handler RepHtml
+postMirrorR = do
+ postedText <- runInputPost $ ireq textField "content"
+ defaultLayout $ do
+ $(widgetFile "posted")
diff --git a/src/Scratch/en/blog/Yesod-tutorial-for-newbies/code/article.hamlet b/src/Scratch/en/blog/Yesod-tutorial-for-newbies/code/article.hamlet
new file mode 100644
index 0000000..6c32d42
--- /dev/null
+++ b/src/Scratch/en/blog/Yesod-tutorial-for-newbies/code/article.hamlet
@@ -0,0 +1,2 @@
+
#{articleTitle article}
+
Articles
+$if null articles
+ -- Show a standard message if there is no article
+
+ $forall Entity articleId article <- articles
+
+
tl;dr: Some hints on how to make great documentation for Haskell libraries.
+Tutorial module containing nothing except documentation.Tutorial module in your cabal descriptiondoctest to check your documentation is up to dateGreat documentation make a big difference. A bad documentation could simply make people not using your lib.
+My friend was learning Haskell. To start he tried a Haskell library to make a small application. The documentation was deprecated to the point he wasn’t able to make a basic example work. How do you believe he felt? What does he thought about Haskell in general?
+So here are my hint on how to make a great documentation in Haskell.
+Documentation can take many different form.
+Tutorial (or Guide.GuideTopic)Tutorial module content:{-# OPTIONS_GHC -fno-warn-unused-imports #-}
+{-|
+ Use @my-package@ if you want to ...
+-}
+module Data.Duration.Tutorial (
+
+ -- * Introduction
+ -- $introduction
+
+ -- ** Subsection
+ -- $subsection
+
+ ) where
+
+import Data.Duration
+
+{- $introduction
+
+So here how you use it:
+
+ >>> humanReadableDuration 1002012.002
+ "11 days 14 hours 20 min 12s 2ms"
+
+The function is 'humanReadableDuration' and
+the you'll be able to click on it to go
+to its definition.
+
+You can add images: <<path-to-image.png title>>
+and links: <http://haskell-lang.org haskell>.
+
+-}
+
+{- $subsection
+
+This is a chuck of documentation
+not attached to any particular Haskell
+declaration with an untested code block:
+
+> answer = 42
+
+-}To prevent obsolescence of your tutorial, use doctest.
That way when you’ll do a stack test or cabal test you’ll get errors if some example doesn’t work anymore.
doctest is a great way to provide examples in your code documentation. These example will then be used as tests. Apparently it comes from Python community.
To use doctest, this is very simple:
-- | My function description
+--
+-- >>> myFunction 3 4
+-- 7
+myFunction :: Int -> Int -> Int
+myFunction = (+)And to make it works simply verify you have a test bloc in your .cabal file looking like this:
test-suite doctest
+ type: exitcode-stdio-1.0
+ hs-source-dirs: test
+ main-is: DocTest.hs
+ build-depend: base >= 4.7 && < 5
+ , <YOUR_LIBRARY>
+ , Glob >= 0.7
+ , doctest >= 0.9.12and in test/DocTest.hs simply use
module Main where
+
+import DocTest
+import System.FilePath.Glob (glob)
+
+main = glob "src/**/*.hs" >>= docTestNow stack test or cabal test will check the validity of your documentation.
stack install haddock or cabal install haddock> haddock src/**/*.hs
+Haddock coverage:
+ 100% ( 15 / 15) in 'Data.Duration'
+ 100% ( 3 / 3) in 'Data.Duration.Tutorial'There are plenty of alternative solution. I provide the one I believe would be used by most people. So if you use github simply create an account on travis.
Add a .travis.yml file in your repo containing the content of the file here and remove the builds you don’t need. It will build your project using a lot of different GHC versions and environemnts.
If you are afraid by such its complexity you might just want to use this one:
+sudo: false
+
+addons:
+ apt:
+ packages:
+ - libgmp-dev
+
+# Caching so the next build will be fast too.
+cache:
+ directories:
+ - $HOME/.stack
+
+before_install:
+# Download and unpack the stack executable
+- mkdir -p ~/.local/bin
+- export PATH=$HOME/.local/bin:$PATH
+- travis_retry curl -L https://www.stackage.org/stack/linux-x86_64 | tar xz --wildcards --strip-components=1 -C ~/.local/bin '*/stack'
+
+script:
+ - stack setup && stack --no-terminal --skip-ghc-check testDon’t forget to activate your repo in travis.
+For some bonus points add the build status badge in your README.md file:
Congratulation! Now if you break your documentation examples, you’ll get notified.
+You could add badges to your README.md file.
Here is a list of some: shields.io
If you didn’t declared your package to stackage, please do it. It isn’t much work. Just edit a file to add your package. And you’ll could be able to add another badge:
See Stackage Badges for more informations.
+stackIf you use stack I suggest you to use the tasty-travis template. It will include the boilerplate for:
So edit your ~/.stack/config.yaml like this:
templates:
+ params:
+ author-name: Your Name
+ author-email: your@mail.com
+ copyright: 'Copyright: (c) 2016 Your Name'
+ github-username: yourusername
+ category: DevelopmentAnd then you can create a new projec with:
+stack new my-project tasty-travisEven not doing anything, if you submit your library to hackage, haddock should generate some API documentation for free.
+But to make real documentation you need to add some manual annotations.
+Functions:
+-- | My function description
+myFunction :: T1 -- ^ arg1 description
+ -> T2 -- ^ arg2 description
+myFunction arg1 arg2 = ...Data:
+data MyData a b
+ = C1 a b -- ^ doc for constructor C1
+ | C2 a b -- ^ doc for constructor C2
+
+data MyData a b
+ = C { a :: TypeA -- ^ field a description
+ , b :: TypeB -- ^ field b description
+ }Module:
+{-|
+Module : MyModule
+Description: Short description
+Copyright : (c)
+License : MIT
+
+Here is a longer description of this module.
+With some code symbol @MyType@.
+And also a block of code:
+
+@
+data MyData = C Int Int
+
+myFunction :: MyData -> Int
+@
+
+-}Documentation Structure:
+module MyModule (
+ -- * Classes
+ C(..),
+ -- * Types
+ -- ** A data type
+ T,
+ -- ** A record
+ R,
+ -- * Some functions
+ f, g
+ ) whereThat will generate headings.
+In Haskell we have great tools like hayoo! and hoogle.
And hackage and stackage provide also a lot of informations.
But generally we lack a lot of Tutorials and Guides. This post was an attempt to help people making more of them.
+But there are other good ideas to help improve the situation.
+In clojure when you create a new project using lein new my-project a directory doc is created for you. It contains a file with a link to this blog post:
If you try to search for some clojure function on a search engine there is a big chance the first result will link to:
+clojuredocs.org: try to search for reduce, update-in or index for exampleFor each symbol necessiting a documentation. You don’t only have the details and standard documentation. You’ll also get:
+clojuredocs.org is an independant website from the official Clojure website.
Most of the time, if you google the function you search you end up on clojuredocs for wich there are many contributions.
+Currently stackage is closer to these feature than hackage. Because on stackage you have access to the README and also some comments by package.
+I believe it would be more efficient to have at least a page by module and why not a page by symbol (data, functions, typeclasses…).
+For example, we could provide details about foldl for example. Also as there would be less information to display, it will make the design cleaner.
Today, if you want to help documenting, you need to make a PR to the source of some library. While if we had an equivalent to clojuredocs for Haskell, adding documentation would simply be a few clicks away:
+There are more than 23k people on /r/haskell. If only 1% of them would take 10 minutes adding a bit of documentation it will certainly change a lot of things in the percieved documentation quality.
And last but not least,
+
+Design is a vague word. A good design should care not only about how something look, but also how users will interact with it. For example by removing things to focus on the essential.
+When I stumble upon some random blog post or random specification in the Haskell community, I had too much a feeling of old fashioned design.
+If you look at node.js community lot of their web page look cleaner, easier to read and in the end, more user friendly.
+Haskell is very different from node, I wouldn’t like to replace all long and precise documentation with short human unprecise concepts. I don’t want to transform scientific papers by tweets.
+But like the scientific community has upgraded with the use of LaTeX, I believe we could find something similar that would make, very clean environment for most of us. A kind of look and feel that will be
+
+
+tl;dr: How to use vim as a very efficient IDE
+In Learn Vim Progressively I’ve show how Vim is great for editing text, and navigating in the same file (buffer). In this short article you’ll see how I use Vim as an IDE. Mainly by using some great plugins.
+There are a lot of Vim plugins. To manage them I use vim-plug.
To install it:
+mkdir -p ~/.vim/autoload
+curl -fLo ~/.vim/autoload/plug.vim \
+ https://raw.githubusercontent.com/junegunn/vim-plug/master/plug.vim☞ Note I have two parts in my .vimrc. The first part contains the list of all my plugins. The second part contains the personal preferences I setted for each plugin. I’ll separate each part by ... in the code.
+Before anything, you should protect your eyes using a readable and low contrast colorscheme.
+For this I use solarized dark. To add it, you only have to write this in your ~/.vimrc file:
call plug#begin('~/.vim/plugged')
+
+Plug 'altercation/vim-colors-solarized'
+
+call plug#end()
+
+" -- solarized personal conf
+set background=dark
+try
+ colorscheme solarized
+catch
+endtryYou should be able to see and destroy trailing whitespaces.
+
+Plug 'bronson/vim-trailing-whitespace'You can clean trailing whitespace with :FixWhitespace.
And also you should see your 80th column.
+if (exists('+colorcolumn'))
+ set colorcolumn=80
+ highlight ColorColumn ctermbg=9
+endif
+One of the most important hidden skills in programming is the ability to search and find files in your projects.
+The majority of people use something like NERDTree. This is the classical left column with a tree of files of your project. I stopped to use this. And you should probably too.
I switched to unite. No left column lost. Faster to find files. Mainly it works like Spotlight on OS X.
+First install ag (the silver search). If you don’t know ack or ag your life is going to be upgraded. This is a simple but essential tool. It is mostly a grep on steroids.
" Unite
+" depend on vimproc
+" ------------- VERY IMPORTANT ------------
+" you have to go to .vim/plugin/vimproc.vim and do a ./make
+" -----------------------------------------
+Plug 'Shougo/vimproc.vim'
+Plug 'Shougo/unite.vim'
+
+...
+
+let g:unite_source_history_yank_enable = 1
+try
+ let g:unite_source_rec_async_command='ag --nocolor --nogroup -g ""'
+ call unite#filters#matcher_default#use(['matcher_fuzzy'])
+catch
+endtry
+" search a file in the filetree
+nnoremap <space><space> :split<cr> :<C-u>Unite -start-insert file_rec/async<cr>
+" reset not it is <C-l> normally
+:nnoremap <space>r <Plug>(unite_restart)Now type space twice. A list of files appears. Start to type some letters of the file you are searching for. Select it, type return and bingo the file opens in a new horizontal split.
+
+If something goes wrong just type <space>r to reset the unite cache.
Now you are able to search file by name easily and efficiently.
+Now search text in many files. For this you use ag:
Plug 'rking/ag.vim'
+...
+" --- type ° to search the word in all files in the current dir
+nmap ° :Ag <c-r>=expand("<cword>")<cr><cr>
+nnoremap <space>/ :AgDon’t forget to add a space after the :Ag.
These are two of the most powerful shortcut for working in a project. using ° which is nicely positioned on my azerty keyboard. You should use a key close to *.
So what ° is doing? It reads the string under the cursor and search for it in all files. Really useful to search where a function is used.
If you type <space>/ followed by a string, it will search for all occurrences of this string in the project files.
So with this you should already be able to navigate between files very easily.
+
+Show which line changed since your last commit.
+Plug 'airblade/vim-gitgutter'And the “defacto” git plugin:
+Plug 'tpope/vim-fugitive'You can reset your changes from the latest git commit with :Gread. You can stage your changes with :Gwrite.
+Plug 'junegunn/vim-easy-align'
+
+...
+
+" Easy align interactive
+vnoremap <silent> <Enter> :EasyAlign<cr>Just select and type Return then space. Type Return many type to change the alignments.
If you want to align the second column, Return then 2 then space.
+C-n & C-pVim has a basic auto completion system. The shortcuts are C-n and C-p while you are in insert mode. This is generally good enough in most cases. For example when I open a file not in my configured languages.
My current Haskell programming environment is great!
+Each time I save a file, I get a comment pointing to my errors or proposing me how to improve my code.
+So here we go:
+++☞ Don’t forget to install
+ghc-modwith:cabal install ghc-mod
" ---------- VERY IMPORTANT -----------
+" Don't forget to install ghc-mod with:
+" cabal install ghc-mod
+" -------------------------------------
+
+Plug 'scrooloose/syntastic' " syntax checker
+" --- Haskell
+Plug 'yogsototh/haskell-vim' " syntax indentation / highlight
+Plug 'enomsg/vim-haskellConcealPlus' " unicode for haskell operators
+Plug 'eagletmt/ghcmod-vim'
+Plug 'eagletmt/neco-ghc'
+Plug 'Twinside/vim-hoogle'
+Plug 'pbrisbin/html-template-syntax' " Yesod templates
+
+...
+
+" -------------------
+" Haskell
+" -------------------
+let mapleader="-"
+let g:mapleader="-"
+set tm=2000
+nmap <silent> <leader>ht :GhcModType<CR>
+nmap <silent> <leader>hh :GhcModTypeClear<CR>
+nmap <silent> <leader>hT :GhcModTypeInsert<CR>
+nmap <silent> <leader>hc :SyntasticCheck ghc_mod<CR>:lopen<CR>
+let g:syntastic_mode_map={'mode': 'active', 'passive_filetypes': ['haskell']}
+let g:syntastic_always_populate_loc_list = 1
+nmap <silent> <leader>hl :SyntasticCheck hlint<CR>:lopen<CR>
+
+" Auto-checking on writing
+autocmd BufWritePost *.hs,*.lhs GhcModCheckAndLintAsync
+
+" neocomplcache (advanced completion)
+autocmd BufEnter *.hs,*.lhs let g:neocomplcache_enable_at_startup = 1
+function! SetToCabalBuild()
+ if glob("*.cabal") != ''
+ set makeprg=cabal\ build
+ endif
+endfunction
+autocmd BufEnter *.hs,*.lhs :call SetToCabalBuild()
+
+" -- neco-ghc
+let $PATH=$PATH.':'.expand("~/.cabal/bin")Just enjoy!
+
+I use - for my leader because I use , a lot for its native usage.
-ht will highlight and show the type of the block under the cursor.-hT will insert the type of the current block.-hh will unhighlight the selection.
+
+My main language at work is Clojure. And my current vim environment is quite good. I lack the automatic integration to lein-kibit thought. If I have the courage I might do it myself one day. But due to the very long startup time of clojure, I doubt I’ll be able to make a useful vim plugin.
So mainly you’ll have real rainbow-parenthesis (the default values are broken for solarized).
+I used the vim paredit plugin before. But it is too restrictive. Now I use sexp which feel more coherent with the spirit of vim.
" " -- Clojure
+Plug 'kien/rainbow_parentheses.vim'
+Plug 'guns/vim-clojure-static'
+Plug 'guns/vim-sexp'
+Plug 'tpope/vim-repeat'
+Plug 'tpope/vim-fireplace'
+
+...
+
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl RainbowParenthesesActivate
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl RainbowParenthesesLoadRound
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl RainbowParenthesesLoadSquare
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl RainbowParenthesesLoadBraces
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl setlocal iskeyword+=?,-,*,!,+,/,=,<,>,.,:
+" -- Rainbow parenthesis options
+let g:rbpt_colorpairs = [
+ \ ['darkyellow', 'RoyalBlue3'],
+ \ ['darkgreen', 'SeaGreen3'],
+ \ ['darkcyan', 'DarkOrchid3'],
+ \ ['Darkblue', 'firebrick3'],
+ \ ['DarkMagenta', 'RoyalBlue3'],
+ \ ['darkred', 'SeaGreen3'],
+ \ ['darkyellow', 'DarkOrchid3'],
+ \ ['darkgreen', 'firebrick3'],
+ \ ['darkcyan', 'RoyalBlue3'],
+ \ ['Darkblue', 'SeaGreen3'],
+ \ ['DarkMagenta', 'DarkOrchid3'],
+ \ ['Darkblue', 'firebrick3'],
+ \ ['darkcyan', 'SeaGreen3'],
+ \ ['darkgreen', 'RoyalBlue3'],
+ \ ['darkyellow', 'DarkOrchid3'],
+ \ ['darkred', 'firebrick3'],
+ \ ]Working with Clojure will becomre quite smoother. You can eval any part of your code, you must launch a Clojure REPL manually in another terminal thought.
+I hope it will be useful.
+Last but not least, if you want to use my vim configuration you can get it here:
+]]>
+
+tl;dr: Install Haskell (OS X and Linux only) by pasting the following in your terminal:
+curl https://raw.githubusercontent.com/yogsototh/install-haskell/master/install-haskell.sh | sudo zshupdate (28 march 2015): I now use Haskell LTS instead of a random stackage version.
+If you are on windows, just download the Haskell Platform and follow the instruction to use Haskell LTS.
+If you want to know the why and the how; you should read the entire article.
+The main weakness of Haskell as nothing to do with the language itself but with its ecosystem1.
+The main problem I’ll try to address is the one known as cabal hell. The community is really active in fixing the issue. I am very confident that in less than a year this problem will be one of the past. But to work today, I provide an install method that should reduce greatly two effects of cabal hell:
+With my actual installation method, you should minimize your headache and almost never hit a dependency error. But there could exists some. If you encounter any dependency error, ask gently to the package manager to port its package to stackage.
+So to install copy/paste the following three lines in your terminal:
+curl https://raw.githubusercontent.com/yogsototh/install-haskell/master/install-haskell.sh | sudo zshYou can read the script and you will see that this is quite straightforward.
+GHC binary for you system and install it.cabal program.As the version of libraries is fixed up until you update the Haskell LTS version, you should never use cabal sandbox. That way, you will only compile each needed library once. The compiled objects/binaries will be in your ~/.cabal directory.
This script use the latest Haskell LTS. So if you use this script at different dates, the Haskell LTS might have changed.
+While it comes to cabal hell, some solutions are sandboxes and nix. Unfortunately, sandboxes didn’t worked good enough for me after some time. Furthermore, sandboxes forces you to re-compile everything by project. If you have three yesod projects for example it means a lot of time and CPU. Also, nix didn’t worked as expected on OS X. So fixing the list of package to a stable list of them seems to me the best pragmatic way to handle the problem today.
From my point of view, Haskell LTS is the best step in the right direction. The actual cabal hell problem is more a human problem than a tool problem. This is a bias in most programmer to prefer resolve social issues using tools. There is nothing wrong with hackage and cabal. But for a package manager to work in a static typing language as Haskell, packages must work all together. This is a great strength of static typed languages that they ensure that a big part of the API between packages are compatible. But this make the job of package managing far more difficult than in dynamic languages.
+People tend not to respect the rules in package numbering2. They break their API all the time. So we need a way to organize all of that. And this is precisely what Haskell LTS provide. A set of stable packages working all together. So if a developer break its API, it won’t work anymore in stackage. And whether the developer fix its package or all other packages upgrade their usage. During this time, Haskell LTS end-users will be able to develop without dependency issues.
++The image of the cat about to jump that I slightly edited can found here +
+By ecosystem of a language I mean, the community, the tools, the documentations, the deployment environments, the businesses using the language, etc… Mainly everything that has nothing to do with the detail of a programming language but has to do on how and why we use it.↩
I myself am guilty of such behavior. It was a beginner error.↩
+
+tl;dr: Learn how to start a new Haskell project. Translate a starter tool written in zsh in Haskell using its own result.
++“Good Sir Knight, will you come with me to Camelot, and join us at the Round Table?”
+
In order to work properly with Haskell you need to initialize your environment. Typically, you need to use a cabal file, create some test for your code. Both, unit test and propositional testing (random and exhaustive up to a certain depth). You need to use git and generally hosting it on github. Also, it is recommended to use cabal sandboxes. And as bonus, an auto-update tool that recompile and retest on each file save.
In this article, we will create such an environment using a zsh script. Then we will write a Haskell project which does the same work as the zsh script. You will then see how to work in such an environment.
+If you are starting to understand Haskell but consider yourself a beginner, this tutorial will show you how to make a real application using quite surprisingly a lot of features:
+☞ zsh is by its nature more suitable to file manipulation. But the Haskell code is clearly more organized while quite terse for a multi-purpose language.
+☞ holy-project is on hackage. It can be installed with cabal update && cabal install holy-project.
I recently read this excellent article: How to Start a New Haskell Project.
+While the article is very good, I lacked some minor informations1. Inspired by it, I created a simple script to initialize a new Haskell project. During the process I improved some things a bit.
+If you want to use this script, the steps are:
+cabal-install (at least 1.18)# Download the script
+git clone https://github.com/yogsototh/init-haskell-project.git
+# Copy the script in a directory of you PATH variable
+cp init-haskell-project/holy-haskell.sh ~/bin
+# Go to the directory containing all your projects
+cd my/projects/directory
+# Launch thcript
+holy-haskell.shWhat does this script do that cabal init doesn’t do?
git with the right .gitignore file.tasty to organize your tests (HUnit, QuickCheck and SmallCheck).-Wall for ghc compilation.zsh really?
+Developing the script in zsh was easy. But considering its size, it is worth to rewrite it in Haskell. Furthermore, it will be a good exercise.
In a first time, we initialize a new Haskell project with holy-haskell.sh:
+> ./holy-haskell.sh +Bridgekeeper: Stop! +Bridgekeeper: Who would cross the Bridge of Death +Bridgekeeper: must answer me these questions three, +Bridgekeeper: ere the other side he see. +You: Ask me the questions, bridgekeeper, I am not afraid. + +Bridgekeeper: What is the name of your project? +> Holy project +Bridgekeeper: What is your name? (Yann Esposito (Yogsototh)) +> +Bridgekeeper: What is your email? (Yann.Esposito@gmail.com) +> +Bridgekeeper: What is your github user name? (yogsototh) +> +Bridgekeeper: What is your project in less than ten words? +> Start your Haskell project with cabal, git and tests. +Initialize git +Initialized empty Git repository in .../holy-project/.git/ +Create files + .gitignore + holy-project.cabal + Setup.hs + LICENSE (MIT) + test/Test.hs + test/HolyProject/Swallow/Test.hs + src/HolyProject/Swallow.hs + test/HolyProject/Coconut/Test.hs + src/HolyProject/Coconut.hs + src/HolyProject.hs + src/Main.hs +Cabal sandboxing, install and test +... + many compilations lines +... +Running 1 test suites... +Test suite Tests: RUNNING... +Test suite Tests: PASS +Test suite logged to: dist/test/holy-project-0.1.0.0-Tests.log +1 of 1 test suites (1 of 1 test cases) passed. +All Tests + Swallow + swallow test: OK + coconut + coconut: OK + coconut property: OK + 148 tests completed + +All 3 tests passed + + + +Bridgekeeper: What... is the air-speed velocity of an unladen swallow? +You: What do you mean? An African or European swallow? +Bridgekeeper: Huh? I... I don't know that. +[the bridgekeeper is thrown over] +Bridgekeeper: Auuuuuuuuuuuugh +Sir Bedevere: How do you know so much about swallows? +You: Well, you have to know these things when you're a king, you know. ++
The different steps are:
+Features to note:
+~/.gitconfig file in order to provide a default name and email.So, apparently nothing too difficult to achieve.
+We should now have an initialized Haskell environment for us to work. The first thing you should do, is to go into this new directory and launch ‘./auto-update’ in some terminal. I personally use tmux on Linux or the splits in iTerm 2 on Mac OS X. Now, any modification of a source file will relaunch a compilation and a test.
+To print the introduction text in zsh:
# init colors
+autoload colors
+colors
+for COLOR in RED GREEN YELLOW BLUE MAGENTA CYAN BLACK WHITE; do
+ eval $COLOR='$fg_no_bold[${(L)COLOR}]'
+ eval BOLD_$COLOR='$fg_bold[${(L)COLOR}]'
+done
+eval RESET='$reset_color'
+# functions
+bk(){print -- "${GREEN}Bridgekeeper: $*${RESET}"}
+bkn(){print -n -- "${GREEN}Bridgekeeper: $*${RESET}"}
+you(){print -- "${YELLOW}You: $*${RESET}"}
+...
+# the introduction dialog
+bk "Stop!"
+bk "Who would cross the Bridge of Death"
+bk "must answer me these questions three,"
+bk "ere the other side he see."
+you "Ask me the questions, bridgekeeper, I am not afraid.\n"
+...
+# the final dialog
+print "\n\n"
+bk "What... is the air-speed velocity of an unladen swallow?"
+you "What do you mean? An African or European swallow?"
+bk "Huh? I... I don't know that."
+log "[the bridgekeeper is thrown over]"
+bk "Auuuuuuuuuuuugh"
+log "Sir Bedevere: How do you know so much about swallows?"
+you "Well, you have to know these things when you're a king, you know."In the first Haskell version I don’t use colors. We see we can almost copy/paste. I just added the types.
+bk :: String -> IO ()
+bk str = putStrLn $ "Bridgekeeper: " ++ str
+
+bkn :: String -> IO ()
+bkn str = pustStr $ "Bridgekeeper: " ++ str
+
+you :: String -> IO ()
+you str = putStrLn $ "You: " ++ str
+
+intro :: IO ()
+intro = do
+ bk "Stop!"
+ bk "Who would cross the Bridge of Death"
+ bk "must answer me these questions three,"
+ bk "ere the other side he see."
+ you "Ask me the questions, bridgekeeper, I am not afraid.\n"
+
+end :: IO ()
+end = do
+ putStrLn "\n\n"
+ bk "What... is the air-speed velocity of an unladen swallow?"
+ you "What do you mean? An African or European swallow?"
+ bk "Huh? I... I don't know that."
+ putStrLn "[the bridgekeeper is thrown over]"
+ bk "Auuuuuuuuuuuugh"
+ putStrLn "Sir Bedevere: How do you know so much about swallows?"
+ you "Well, you have to know these things when you're a king, you know."Now let’s just add the colors using the ansi-terminal package. So we have to add ansi-terminal as a build dependency in our cabal file.
Edit holy-project.cabal to add it.
...
+build-depends: base >=4.6 && <4.7
+ , ansi-terminal
+...Now look at the modified Haskell code:
+import System.Console.ANSI
+
+colorPutStr :: Color -> String -> IO ()
+colorPutStr color str = do
+ setSGR [ SetColor Foreground Dull color
+ , SetConsoleIntensity NormalIntensity
+ ]
+ putStr str
+ setSGR []
+
+
+bk :: String -> IO ()
+bk str = colorPutStr Green ("Bridgekeeper: " ++ str ++ "\n")
+bkn :: String -> IO ()
+bkn str = colorPutStr Green ("Bridgekeeper: " ++ str)
+you :: String -> IO ()
+you str = colorPutStr Yellow ("You: " ++ str ++ "\n")
+
+intro :: IO ()
+intro = do
+ bk "Stop!"
+ bk "Who would cross the Bridge of Death"
+ bk "must answer me these questions three,"
+ bk "ere the other side he see."
+ you "Ask me the questions, bridgekeeper, I am not afraid.\n"
+
+end :: IO ()
+end = do
+ putStrLn "\n\n"
+ bk "What... is the air-speed velocity of an unladen swallow?"
+ you "What do you mean? An African or European swallow?"
+ bk "Huh? I... I don't know that."
+ putStrLn "[the bridgekeeper is thrown over]"
+ bk "Auuuuuuuuuuuugh"
+ putStrLn "Sir Bedevere: How do you know so much about swallows?"
+ you "Well, you have to know these things when you're a king, you know."We could put this code in src/Main.hs. Declare a main function:
main :: IO ()
+main = do
+ intro
+ endMake cabal install and run cabal run (or ./.cabal-sandbox/bin/holy-project). It works!
+In order to ask questions, here is how we do it in shell script:
+ +If we want to abstract things a bit, the easiest way in shell is to use a global variable2 which will get the value of the user input like this:
+answer=""
+ask(){
+ local info="$1"
+ bk "What is your $info?"
+ print -n "> "
+ read answer
+}
+...
+ask name
+name="$answer"In Haskell we won’t need any global variable:
+import System.IO (hFlush, stdout)
+...
+ask :: String -> IO String
+ask info = do
+ bk $ "What is your " ++ info ++ "?"
+ putStr "> "
+ hFlush stdout -- Because we want to ask on the same line.
+ getLineNow our main function might look like:
+main = do
+ intro
+ _ <- ask "project name"
+ _ <- ask "name"
+ _ <- ask "email"
+ _ <- ask "github account"
+ _ <- ask "project in less than a dozen word"
+ endYou could test it with cabal install and then ./.cabal-sandbox/bin/holy-project.
We will see later how to guess the answer using the .gitconfig file and the github API.
+I don’t really like the ability to use capital letter in a package name. So in shell I transform the project name like this:
+ +In order to achieve the same result in Haskell (don’t forget to add the split package):
import Data.Char (toLower)
+import Data.List (intercalate)
+import Data.List.Split (splitOneOf)
+...
+projectNameFromString :: String -> String
+projectNameFromString str = intercalate "-" (splitOneOf " -" (map toLower str))One important thing to note is that in zsh the transformation occurs on strings but in haskell we use list as intermediate representation:
+zsh:
+"Holy grail" ==( ${project:gs/ /-/} )=> "Holy-grail"
+ ==( ${project:l} )=> "holy-grail"
+
+haskell
+"Holy grail" ==( map toLower )=> "holy grail"
+ ==( splitOneOf " -" )=> ["holy","grail"]
+ ==( intercalate "-" )=> "holy-grail"The module name is a capitalized version of the project name where we remove dashes.
+# Capitalize a string
+capitalize(){
+ local str="$(print -- "$*" | sed 's/-/ /g')"
+ print -- ${(C)str} | sed 's/ //g'
+}-- | transform a chain like "Holy project" in "HolyProject"
+capitalize :: String -> String
+capitalize str = concatMap capitalizeWord (splitOneOf " -" str)
+ where
+ capitalizeWord :: String -> String
+ capitalizeWord (x:xs) = toUpper x:map toLower xs
+ capitalizeWord _ = []The haskell version is made by hand where zsh already had a capitalize operation on string with many words. Here is the difference between the shell and haskell way (note I splitted the effect of concatMap as map and concat):
shell:
+"Holy-grail" ==( sed 's/-/ /g' )=> "Holy grail"
+ ==( ${(C)str} )=> "Holy Grail"
+ ==( sed 's/ //g' )=> "HolyGrail"
+
+haskell:
+"Holy-grail" ==( splitOneOf " -" )=> ["Holy","grail"]
+ ==( map capitalizeWord )=> ["Holy","Grail"]
+ ==( concat )=> "HolyGrail"As the preceding example, in shell we work on strings while Haskell use temporary lists representations.
+Also I want to be quite restrictive on the kind of project name we can give. This is why I added a check function.
+ioassert :: Bool -> String -> IO ()
+ioassert True _ = return ()
+ioassert False str = error str
+
+main :: IO ()
+main = do
+ intro
+ project <- ask "project name"
+ ioassert (checkProjectName project)
+ "Use only letters, numbers, spaces and dashes please"
+ let projectname = projectNameFromString project
+ modulename = capitalize projectWhich verify the project name is not empty and use only letter, numbers and dashes:
+-- | verify if project name is conform
+checkProjectName :: String -> Bool
+checkProjectName [] = False
+checkProjectName str =
+ all (\c -> isLetter c || isNumber c || c=='-' || c==' ') str
+Making a project will consists in creating files and directories whose name and content depends on the answer we had until now.
+In shell, for each file to create, we used something like:
+ +In Haskell, while possible, we shouldn’t put the file content in the source code. We have a relatively easy way to include external file in a cabal package. This is what we will be using.
+Furthermore, we need a templating system to replace small part of the static file by computed values. For this task, I choose to use hastache, a Haskell implementation of Mustache templates3.
Cabal provides a way to add files which are not source files to a package. You simply have to add a Data-Files: entry in the header of the cabal file:
data-files: scaffold/LICENSE
+ , scaffold/Setup.hs
+ , scaffold/auto-update
+ , scaffold/gitignore
+ , scaffold/interact
+ , scaffold/project.cabal
+ , scaffold/src/Main.hs
+ , scaffold/src/ModuleName.hs
+ , scaffold/src/ModuleName/Coconut.hs
+ , scaffold/src/ModuleName/Swallow.hs
+ , scaffold/test/ModuleName/Coconut/Test.hs
+ , scaffold/test/ModuleName/Swallow/Test.hs
+ , scaffold/test/Test.hsNow we simply have to create our files at the specified path. Here is for example the first lines of the LICENSE file.
+The MIT License (MIT)
+
+Copyright (c) {{year}} {{author}}
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+...It will be up to our program to replace the {{year}} and {{author}} at runtime. We have to find the files. Cabal will create a module named Paths_holy_project. If we import this module we have the function genDataFileName at our disposal. Now we can read the files at runtime like this:
...
+ do
+ pkgFilePath <- getDataFileName "scaffold/LICENSE"
+ templateContent <- readFile pkgFilePath
+ ...A first remark is for portability purpose we shouldn’t use String for file path. For example on Windows / isn’t considered as a subdirectory character. To resolve this problem we will use FilePath:
import System.Directory
+import System.FilePath.Posix (takeDirectory,(</>))
+...
+createProject ... = do
+ ...
+ createDirectory projectName -- mkdir
+ setCurrentDirectory projectName -- cd
+ genFile "LICENSE" "LICENSE"
+ genFile "gitignore" ".gitignore"
+ genFile "src/Main.hs" ("src" </> "Main.hs")
+
+genFile dataFilename outputFilename = do
+ pkgfileName <- getDataFileName ("scaffold/" ++ filename)
+ template <- readFile pkgfileName
+ transformedFile <- ??? -- hastache magic here
+ createDirectoryIfMissing True (takeDirectory outputFileName)
+ writeFile outputFileName transformedFileIn order to use hastache we can either create a context manually or use generics to create a context from a record. This is the last option we will show here. So in a first time, we need to import some modules and declare a record containing all necessary informations to create our project.
+{-# LANGUAGE DeriveDataTypeable #-}
+...
+import Data.Data
+import Text.Hastache
+import Text.Hastache.Context
+import qualified Data.ByteString as BS
+import qualified Data.ByteString.Lazy.Char8 as LZdata Project = Project {
+ projectName :: String
+ , moduleName :: String
+ , author :: String
+ , mail :: String
+ , ghaccount :: String
+ , synopsis :: String
+ , year :: String
+ } deriving (Data, Typeable)Once we have declared this, we should populate our Project record with the data provided by the user. So our main function should look like:
+main :: IO ()
+main = do
+ intro
+ project <- ask "project name"
+ ioassert (checkProjectName project)
+ "Use only letters, numbers, spaces and dashes please"
+ let projectname = projectNameFromString project
+ modulename = capitalize project
+ in_author <- ask "name"
+ in_email <- ask "email"
+ in_ghaccount <- ask "github account"
+ in_synopsis <- ask "project in less than a dozen word?"
+ current_year <- getCurrentYear
+ createProject $ Project projectname modulename in_author in_email
+ in_ghaccount in_synopsis current_year
+ endFinally we could use hastache this way:
+createProject :: Project -> IO ()
+createProject p = do
+ let context = mkGenericContext p
+ createDirectory (projectName p)
+ setCurrentDirectory (projectName p)
+ genFile context "gitignore" $ ".gitignore"
+ genFile context "project.cabal" $ (projectName p) ++ ".cabal"
+ genFile context "src/Main.hs") $ "src" </> "Main.hs"
+ ...
+
+genFile :: MuContext IO -> FilePath -> FilePath -> IO ()
+genFile context filename outputFileName = do
+ pkgfileName <- getDataFileName ("scaffold/"++filename)
+ template <- BS.readFile pkgfileName
+ transformedFile <- hastacheStr defaultConfig template context
+ createDirectoryIfMissing True (takeDirectory outputFileName)
+ LZ.writeFile outputFileName transformedFileWe use external files in mustache format. We ask question to our user to fill a data structure. We use this data structure to create a context. Hastache use this context with the external files to create the project files.
+
+We need to initialize git and cabal. For this we simply call external command with the system function.
import System.Cmd
+
+...
+main = do
+ ...
+ _ <- system "git init ."
+ _ <- system "cabal sandbox init"
+ _ <- system "cabal install"
+ _ <- system "cabal test"
+ _ <- system $ "./.cabal-sandbox/bin/test-" ++ projectNameOur job is almost finished. Now, we only need to add some nice feature to make the application more enjoyable.
+
+The first one would be to add a better error message.
+import System.Random
+
+holyError :: String -> IO ()
+holyError str = do
+ r <- randomIO
+ if r
+ then
+ do
+ bk "What... is your favourite colour?"
+ you "Blue. No, yel..."
+ putStrLn "[You are thrown over the edge into the volcano]"
+ you "You: Auuuuuuuuuuuugh"
+ bk " Hee hee heh."
+ else
+ do
+ bk "What is the capital of Assyria?"
+ you "I don't know that!"
+ putStrLn "[You are thrown over the edge into the volcano]"
+ you "Auuuuuuuuuuuugh"
+ error ('\n':str)And also update where this can be called
+ioassert :: Bool -> String -> IO ()
+ioassert True _ = return ()
+ioassert False str = holyError str.gitconfigWe want to retrieve the ~/.gitconfig file content and see if it contains a name and email information. We will need to access to the HOME environment variable. Also, as we use bytestring package for hastache, let’s take advantage of this library.
import Data.Maybe (fromJust)
+import System.Environment (getEnv)
+import Control.Exception
+import System.IO.Error
+import Control.Monad (guard)
+
+safeReadGitConfig :: IO LZ.ByteString
+safeReadGitConfig = do
+ e <- tryJust (guard . isDoesNotExistError)
+ (do
+ home <- getEnv "HOME"
+ LZ.readFile $ home ++ "/.gitconfig" )
+ return $ either (const (LZ.empty)) id e
+...
+main = do
+ gitconfig <- safeReadGitConfig
+ let (name,email) = getNameAndMail gitconfig
+ project <- ask "project name" Nothing
+ ...
+ in_author <- ask "name" name
+ ...We could note I changed the ask function slightly to take a maybe parameter.
+ask :: String -> Maybe String -> IO String
+ask info hint = do
+ bk $ "What is your " ++ info ++ "?" ++ (maybe "" (\h -> " ("++h++")") hint)
+ ...Concerning the parsing of .gitconfig, it is quite minimalist.
getNameAndMail :: LZ.ByteString -> (Maybe String,Maybe String)
+getNameAndMail gitConfigContent = (getFirstValueFor splitted "name",
+ getFirstValueFor splitted "email")
+ where
+ -- make lines of words
+ splitted :: [[LZ.ByteString]]
+ splitted = map LZ.words (LZ.lines gitConfigContent)
+
+-- Get the first line which start with
+-- 'elem =' and return the third field (value)
+getFirstValueFor :: [[LZ.ByteString]] -> String -> Maybe String
+getFirstValueFor splitted key = firstJust (map (getValueForKey key) splitted)
+
+-- return the first Just value of a list of Maybe
+firstJust :: (Eq a) => [Maybe a] -> Maybe a
+firstJust l = case dropWhile (==Nothing) l of
+ [] -> Nothing
+ (j:_) -> j
+
+-- Given a line of words ("word1":"word2":rest)
+-- getValue will return rest if word1 == key
+-- 'elem =' or Nothing otherwise
+getValueForKey :: String -- key
+ -> [LZ.ByteString] -- line of words
+ -> Maybe String -- the value if found
+getValueForKey el (n:e:xs) = if (n == (LZ.pack el)) && (e == (LZ.pack "="))
+ then Just (LZ.unpack (LZ.unwords xs))
+ else Nothing
+getValueForKey _ _ = NothingWe could notice, getNameAndMail doesn’t read the full file and stop at the first occurrence of name and mail.
+The task seems relatively easy, but we’ll see there will be some complexity hidden. Make a request on https://api.github.com/search/users?q=<email>. Parse the JSON and get the login field of the first item.
So the first problem to handle is to connect an URL. For this we will use the http-conduit package.
Generally, for simple request, we should use:
+ +But, after some research, I discovered we must declare an User-Agent in the HTTP header to be accepted by the github API. So we have to change the HTTP Header, and our code became slightly more complex:
+{-# LANGUAGE OverloadedStrings #-}
+...
+simpleHTTPWithUserAgent :: String -> IO LZ.ByteString
+simpleHTTPWithUserAgent url = do
+ r <- parseUrl url
+ let request = r { requestHeaders = [ ("User-Agent","HTTP-Conduit") ] }
+ withManager $ (return.responseBody) <=< httpLbs request
+
+getGHUser :: String -> IO (Maybe String)
+getGHUser "" = return Nothing
+getGHUser email = do
+ let url = "https://api.github.com/search/users?q=" ++ email
+ body <- simpleHTTPWithUserAgent url
+ ...So now, we have a String containing a JSON representation. In javascript we would have used login=JSON.parse(body).items[0].login. How does Haskell will handle it (knowing the J in JSON is for Javascript)?
First we will need to add the lens-aeson package and use it that way:
import Control.Lens.Operators ((^?))
+import Control.Lens.Aeson
+import Data.Aeson.Encode (fromValue)
+import qualified Data.Text.Lazy as TLZ
+import qualified Data.Text.Lazy.Builder as TLB
+
+getGHUser :: String -> IO (Maybe String)
+getGHUser email = do
+ let url = "https://api.github.com/search/users?q=" ++ email
+ body <- simpleHTTPWithUserAgent url
+ let login = body ^? key "items" . nth 0 . key "login"
+ return $ fmap jsonValueToString login
+ where
+ jsonValueToString = TLZ.unpack . TLB.toLazyText . fromValueIt looks ugly, but it’s terse. In fact each function (^?), key and nth has some great mathematical properties and everything is type safe. Unfortunately I had to make my own jsonValueToString. I hope I simply missed a simpler existing function.
You can read this article on lens-aeson and prisms to know more.
+We now have all the feature provided by the original zsh script shell. But here is a good occasion to use some Haskell great feature.
We will launch the API request sooner and in parallel to minimize our wait time:
+import Control.Concurrent
+...
+main :: IO ()
+main = do
+ intro
+ gitconfig <- safeReadGitConfig
+ let (name,email) = getNameAndMail gitconfig
+ earlyhint <- newEmptyMVar
+ maybe (putMVar earlyhint Nothing) -- if no email found put Nothing
+ (\hintmail -> do -- in the other case request the github API
+ forkIO (putMVar earlyhint =<< getGHUser hintmail)
+ return ())
+ email
+ project <- ask "project name" Nothing
+ ioassert (checkProjectName project)
+ "Use only letters, numbers, spaces and dashes please"
+ let projectname = projectNameFromString project
+ modulename = capitalize project
+ in_author <- ask "name" name
+ in_email <- ask "email" email
+ ghUserHint <- if maybe "" id email /= in_email
+ then getGHUser in_email
+ else takeMVar earlyhint
+ in_ghaccount <- ask "github account" ghUserHint
+ in_synopsis <- ask "project in less than a dozen word?" Nothing
+ current_year <- getCurrentYear
+ createProject $ Project projectname modulename in_author in_email
+ in_ghaccount in_synopsis current_year
+ endWhile it might feel a bit confusing, it is in fact quite simple.
+MVar. Mainly a variable which either is empty or contains something.MVar.MVar.If you have a github account and had set correctly your .gitconfig, you might not even wait.
We have a working product. But, I don’t consider our job finished. The code is about 335 lines.
+Considering that we:
+.gitconfigThis is quite few.
+
+For short programs it is not obvious to split them into different modules. But my personal preference is to split it anyway.
+First we put all content of src/Main.hs in src/HolyProject.hs. We rename the main function by holyStarter. And our src/Main.hs should contains:
Of course you have to remember to rename the module of src/HolyProject.hs. I separated all functions in different submodules:
HolyProject.GitConfig
+getNameAndMailFromGitConfig: retrieve name an email from .gitconfig fileHolyProject.GithubAPI
+searchGHUser: retrieve github user name using github API.HolyProject.MontyPython
+bk: bridge keeper speaksyou: you speakask: Ask a question and wait for an answerHolyProject.StringUtils: String helper functions
+projectNameFromStringcapitalizecheckProjectNameThe HolyProject.hs file contains mostly the code that ask questions, show errors and copy files using hastache.
One of the benefits in modularizing the code is that our main code is clearer. Some functions are declared only in a module and are not exported. This help us hide technical details. For example, the modification of the HTTP header to use the github API.
+
+We didn’t take much advantage of the project structure yet. A first thing is to generate some documentation. Before most function I added comment starting with -- |. These comment will be used by haddock to create a documentation. First, you need to install haddock manually.
Be sure to have haddock in your PATH. You could for example add it like this:
And if you are at the root of your project you’ll get it. And now just launch:
+ +And magically, you’ll have a documentation in dist/doc/html/holy-project/index.html.
While the Haskell static typing is quite efficient to prevent entire classes of bugs, Haskell doesn’t discard the need to test to minimize the number of bugs.
+
+It is generally said to test we should use unit testing for code in IO and QuickCheck or SmallCheck for pure code.
+A unit test example on pure code is in the file test/HolyProject/Swallow/Test.hs:
module HolyProject.Swallow.Test
+ (swallowSuite)
+where
+import Test.Tasty (testGroup, TestTree)
+import Test.Tasty.HUnit
+import HolyProject.Swallow (swallow)
+
+swallowSuite :: TestTree
+swallowSuite = testGroup "Swallow"
+ [testCase "swallow test" testSwallow]
+
+-- in Swallow: swallow = (++)
+testSwallow :: Assertion
+testSwallow = "something" @=? swallow "some" "thing"Note swallow is (++). We group tests by group. Each group can contain some test suite. Here we have a test suite with only one test. The (@=?) verify the equality between its two parameters.
So now, we could safely delete the directory test/HolyProject/Swallow and the file src/HolyProject/Swallow.hs. And we are ready to make our own real world unit test. We will first test the module HolyProject.GithubAPI. Let’s create a file test/HolyProject/GithubAPI/Test.hs with the following content:
module HolyProject.GithubAPI.Test
+( githubAPISuite
+) where
+import Test.Tasty (testGroup, TestTree)
+import Test.Tasty.HUnit
+import HolyProject.GithubAPI
+
+githubAPISuite :: TestTree
+githubAPISuite = testGroup "GithubAPI"
+ [ testCase "Yann" $ ioTestEq
+ (searchGHUser "Yann.Esposito@gmail.com")
+ (Just "\"yogsototh\"")
+ , testCase "Jasper" $ ioTestEq
+ (searchGHUser "Jasper Van der Jeugt")
+ (Just "\"jaspervdj\"")
+ ]
+
+-- | Test if some IO action returns some expected value
+ioTestEq :: (Eq a, Show a) => IO a -> a -> Assertion
+ioTestEq action expected = action >>= assertEqual "" expectedYou have to modify your cabal file. More precisely, you have to add HolyProject.GithubAPI in the exposed modules of the library secion). You also have to update the test/Test.hs file to use GithubAPI instead of Swallow.
So we have our example of unit testing using IO. We search the github nickname for some people I know and we verify github continue to give the same answer as expected.
+
+When it comes to pure code, a very good method is to use QuickCheck and SmallCheck. SmallCheck will verify all cases up to some depth about some property. While QuickCheck will verify some random cases.
+As this kind of verification of property is mostly doable on pure code, we will test the StringUtils module.
So don’t forget to declare HolyProject.StringUtils in the exposed modules in the library section of your cabal file. Remove all references to the Coconut module.
Modify the test/Test.hs to remove all references about Coconut. Create a test/HolyProject/StringUtils/Test.hs file containing:
module HolyProject.StringUtils.Test
+( stringUtilsSuite
+) where
+import Test.Tasty (testGroup, TestTree)
+import Test.Tasty.SmallCheck (forAll)
+import qualified Test.Tasty.SmallCheck as SC
+import qualified Test.Tasty.QuickCheck as QC
+import Test.SmallCheck.Series (Serial)
+import HolyProject.StringUtils
+
+stringUtilsSuite :: TestTree
+stringUtilsSuite = testGroup "StringUtils"
+ [ SC.testProperty "SC projectNameFromString idempotent" $
+ idempotent projectNameFromString
+ , SC.testProperty "SC capitalize idempotent" $
+ deeperIdempotent capitalize
+ , QC.testProperty "QC projectNameFromString idempotent" $
+ idempotent capitalize
+ ]
+
+idempotent f = \s -> f s == f (f s)
+
+deeperIdempotent :: (Eq a, Show a, Serial m a) => (a -> a) -> SC.Property m
+deeperIdempotent f = forAll $ SC.changeDepth1 (+1) $ \s -> f s == f (f s)The result is here:
++All Tests + StringUtils + SC projectNameFromString idempotent: OK + 206 tests completed + SC capitalize idempotent: OK + 1237 tests completed + QC projectNameFromString idempotent: FAIL + *** Failed! Falsifiable (after 19 tests and 5 shrinks): + "a a" + Use --quickcheck-replay '18 913813783 2147483380' to reproduce. + GithubAPI + Yann: OK + Jasper: OK + +1 out of 5 tests failed ++
The test fail, but this is not an error. Our capitalize function shouldn’t be idempotent. I simply added this test to show what occurs when a test fail. If you want to look more closely to the error you could do this:
$ ./interact
+GHCi, version 7.6.2: http://www.haskell.org/ghc/ :? for help
+Loading package ghc-prim ... linking ... done.
+Loading package integer-gmp ... linking ... done.
+Loading package base ... linking ... done.
+Prelude> :l src/HolyProject/StringUtils
+[1 of 1] Compiling HolyProject.StringUtils ( src/HolyProject/StringUtils.hs, interpreted )
+Ok, modules loaded: HolyProject.StringUtils.
+*HolyProject.StringUtils> capitalize "a a"
+"AA"
+*HolyProject.StringUtils> capitalize (capitalize "a a")
+"Aa"
+*HolyProject.StringUtils>It is important to use ./interact instead of ghci. Because we need to tell ghci how to found the package installed.
Apparently, SmallCheck didn’t found any counter example. I don’t know how it generates Strings and using deeper search is really long.
+
+Congratulation!
+Now you could start programming in Haskell and publish your own cabal package.
+For example, you have to install the test libraries manually to use cabal test.↩
There is no easy way to do something like name=$(ask name). Simply because $(ask name) run in another process which doesn’t get access to the standard input↩
Having a good level of power in templates is very difficult. imho Mustache has made the best compromise.↩
tl;dr: Short introduction to Parsec for beginner.
++From String: +
+(1+3)*(1+5+9)+To data structure: +
+
+
+
+
+tl;dr: Determine with the most objectivity possible the best(s) web framework(s) depending on your needs. Here are the results. Please note the actual ability to take a rational decision is pretty bad for now.
+This is it.
+You’ve got the next big idea.
+You just need to make a very simple web application.
It sounds easy! You just need to choose a good modern web framework, when suddenly:
+![[Choice Paralysis][choice_paralysis]](/Scratch/img/blog/Rational-Web-Framework-Choice/choice_paralysis.gif)
+After your brain stack overflowed, you decide to use a very simple methodology. Answer two questions:
+Which language am I familiar with?
+What is the most popular web framework for this language?
Great! This is it.
+But, you continually hear this little voice.
+++“You didn’t made a bad choice, yes. But …
+
+you hadn’t made the best either.”
This article try to determine in the most objective and rational way the best(s) web framework(s) depending on your needs. To reach this goal, I will provide a decision tool in the result section.
+I will use the following methodology:
+Methodology
+++☞ Important Note
+
+I am far from happy to the actual result. There are a lot of biases, for example in the choice of the parameters. The same can be said about the data I gathered. I am using very imprecise informations. But, as far as I know, this is the only article which use many different parameters to help you choose a web framework.This is why I made a very flexible decision tool:
+ +
Here are the important features (properties/parameters) I selected to make the choice:
+Each feature is quite important and mostly independant from each other. I tried to embrace most important topics concerning web frameworks with these four properties. I am fully concious some people might lack another important feature. Nonetheless the methodology used here can be easily replicated. If you lack an important property add it at will and use this choice method.
+Also each feature is very hard to measure with precision. This is why we will only focus on order of magnitude.
+For each property a framework could have one of the six possible values: Excellent, Very Good, Good, Medium, Bad or Very Bad
+So how to make a decision model from these informations?
+One of the most versatile method is to give a weight for each cluster value. And to select the framework maximizing this score:
+score(framework) = efficiency + robustness + expressiveness + popularity++For example:
++ +
++ +Expressiveness +10 +7 +1 +-∞ +-∞ +-∞ ++ +Popularity +5 +5 +4 +3 +2 +1 ++ +Efficiency +10 +8 +6 +4 +2 +1 ++ + +Robustness +10 +8 +6 +4 +2 +1 +Using this weighted table, that means:
++
+- we discard the three least expressive clusters.
+- We don’t make any difference between excellent and very good in popularity.
+- Concerning efficient framework in excellent cluster will have 2 more points than the “very good” cluster.
+So for each framework we compute its score relatively to a weighted table. And we select the best(s).
+Example: Using this hypothetic framework and the preceeding table.
++ +
++ + + ++ Expressiveness +Popularity +Efficiency +Robustness ++ + +yog +Excellent +Very Bad +Medium +Very Good ++score(yog) = 10 + 0 + 4 + 8 = 22
Most needs should be expressed by such a weighted table. In the result section, we will discuss this further.
+It is now time to try to get these measures.
+None of the four properties I choosen can be measured with perfect precision. But we could get the order of magnitude for each.
+I tried to focus on the framework only. But it is often easier to start by studying the language first.
+For example, I have datas about popularity by language and I also have different datas concerning popularity by framework. Even if I use only the framework focused datas in my final decision model, it seemed important to me to discuss about the datas for the languages. The goal is to provide a tool to help decision not to give a decision for you.
+RedMonk Programming Language Rankings (January 2013) provide an apparent good measure of popularity. While not perfect the current measure feel mostly right. They create an image using stack overflow and github data. Vertical correspond to the number of questions on stackoverflow. Horizontal correspond to the number of projects on github.
+If you look at the image, your eye can see about four clusters. The 1st cluster correspond to mainstream languages:
+![Mainstream Languages Cluster from [RedMonk][redmonk]](/Scratch/img/blog/Rational-Web-Framework-Choice/mainstreamlanguages.png)
+Most developer know at least one of these language.
+The second cluster is quite bigger. It seems to correspond to languages with a solid community behind them.
+![Second tier languages from [RedMonk][redmonk]](/Scratch/img/blog/Rational-Web-Framework-Choice/secondtierlanguages.png)
+I don’t get into detail, but you could also see third and fourth tier popular languages.
+So:
+Mainstream: JavaScript, Java, PHP, Python, Ruby, C#, C++, C, Objective-C, Perl, Shell
Good: Scala, Haskell, Visual Basic, Assembly, R, Matlab, ASP, ActionScript, Coffeescript, Groovy, Clojure, Lua, Prolog
+Medium: Erlang, Go, Delphi, D, Racket, Scheme, ColdFusion, F#, FORTRAN, Arduino, Tcl, Ocaml
+Bad: third tier Very Bad: fourth tier
+I don’t thing I could find easily web frameworks for third or fourth tier languages.
+For now, I only talked about language popularity. But what about framework popularity? I made a test using number of question on stackoverflow only. Then by dividing by two for each 6 cluster:
+| Cluster | +Language | +Framework | +#nb | +% | +
|---|---|---|---|---|
| Excellent | +Ruby | +Rails | +176208 | +100% | +
| Very Good | +Python | +Django | +57385 | +<50% | +
| + | Java | +Servlet | +54139 | ++ |
| + | Java | +Spring | +31641 | ++ |
| + | Node.js | +node.js | +27243 | ++ |
| + | PHP | +Codeigniter | +21503 | ++ |
| + | Groovy | +Grails | +20222 | ++ |
| Good | +Ruby | +Sinatra | +8631 | +<25% | +
| + | Python | +Flask | +7062 | ++ |
| + | PHP | +Laravel | +6982 | ++ |
| + | PHP | +Kohana | +5959 | ++ |
| + | Node.js | +Express | +5009 | ++ |
| Medium | +PHP | +Cake | +4554 | +<13% | +
| + | C♯ | +ServiceStack | +3838 | ++ |
| + | Scala | +Play | +3823 | ++ |
| + | Java | +Wicket | +3819 | ++ |
| + | Dart | +Dart | +3753 | ++ |
| + | PHP | +Slim | +3361 | ++ |
| + | Python | +Tornado | +3321 | ++ |
| + | Scala | +Lift | +2844 | ++ |
| + | Go | +Go | +2689 | ++ |
| Bad | +Java | +Tapestry | +1197 | +<6% | +
| + | C♯ | +aspnet | +1000 | ++ |
| + | Haskell | +Yesod | +889 | ++ |
| + | PHP | +Silex | +750 | ++ |
| + | PHP | +Lithium | +732 | ++ |
| + | C♯ | +nancy | +705 | ++ |
| Very bad | +Java | +Grizzly | +622 | +<3% | +
| + | Erlang | +Cowboy | +568 | ++ |
| + | Perl | +Dancer | +496 | ++ |
| + | PHP | +Symphony2 | +491 | ++ |
| + | Go | +Revel | +459 | ++ |
| + | Clojure | +Compojure | +391 | ++ |
| + | Perl | +Mojolicious | +376 | ++ |
| + | Scala | +Scalatra | +349 | ++ |
| + | Scala | +Finagle | +336 | ++ |
| + | PHP | +Phalcon | +299 | ++ |
| + | js | +Ringo | +299 | ++ |
| + | Java | +Gemini | +276 | ++ |
| + | Haskell | +Snap | +263 | ++ |
| + | Perl | +Plack | +257 | ++ |
| + | Erlang | +Elli | +230 | ++ |
| + | Java | +Dropwizard | +188 | ++ |
| + | PHP | +Yaf | +146 | ++ |
| + | Java | +Play1 | +133 | ++ |
| + | Node.js | +Hapi | +131 | ++ |
| + | Java | +Vertx | +60 | ++ |
| + | Scala | +Unfiltered | +42 | ++ |
| + | C | +onion | +18 | ++ |
| + | Clojure | +http-kit | +17 | ++ |
| + | Perl | +Kelp | +16 | ++ |
| + | PHP | +Micromvc | +13 | ++ |
| + | Lua | +Openresty | +8 | ++ |
| + | C++ | +cpoll-cppsp | +5 | ++ |
| + | Clojure | +Luminus | +3 | ++ |
| + | PHP | +Phreeze | +1 | ++ |
As we can see, our framework popularity indicator can be quite different from its language popularity. For now I didn’t found a nice way to merge the results from RedMonk with these one. So I’ll use these unperfect one. Hopefully the order of magninute is mostly correct for most framework.
+Another objective measure is efficiency. We all know benchmarks are all flawed. But they are the only indicators concerning efficiency we have.
+I used the benchmark from benchmarksgame. Mainly, there are five clusters:
+| 1x→2x | +C, C++ |
+
| 2x→3x | +Java 7, Scala, OCamL, Haskell, Go, Common LISP | +
| 3x→10x | +C♯, Clojure, Racket, Dart | +
| 10x→30x | +Erlang | +
| 30x→ | +PHP, Python, Perl, Ruby, JRuby | +
Remarks concerning some very slow languages:
+This is a first approach. The speed of the language for basic benchmarks. But, here we are interrested in web programming. Fortunately techempower has made some tests focused on most web frameworks:
+ +These benchmark doesn’t fit well with our needs. The values are certainly quite imprecise to your real usage. The goal is just to get an order of magnitude for each framework. Another problem is the high number of informations.
+As always, we should remember these informations are also imprecise. So I simply made some classes of efficiency.
+Remark: I separated the clusters by using power of 2 relatively to the fastest.
+| Cluster | +Language | +Framework | +#nb | +slowness | +
|---|---|---|---|---|
| Excellent | +C++ | +cpoll-cppsp | +114,711 | +1× | +
| + | Jav | +gemini | +105,204 | ++ |
| + | Lua | +openresty | +93,882 | ++ |
| + | Jav | +servlet | +90,580 | ++ |
| + | C++ | +cpoll-pool | +89,167 | ++ |
| + | Go | +go | +76,024 | ++ |
| + | Sca | +finagle | +68,413 | ++ |
| + | Go | +revel | +66,990 | ++ |
| + | Jav | +rest-express | +63,209 | ++ |
| Very Good | +Jav | +wicket | +48,772 | +>2× | +
| + | Sca | +scalatra | +48,594 | ++ |
| + | Clj | +http-kit | +42,703 | ++ |
| + | Jav | +spring | +36,643 | +>3× | +
| + | PHP | +php | +36,605 | ++ |
| + | Jav | +tapestry | +35,032 | ++ |
| + | Clj | +compojure | +32,088 | ++ |
| + | JS | +ringo | +31,962 | ++ |
| + | Jav | +dropwizard | +31,514 | ++ |
| + | Clj | +luminus | +30,672 | ++ |
| Good | +Sca | +play-slick | +29,950 | +>4× | +
| + | Sca | +unfiltered | +29,782 | ++ |
| + | Erl | +elli | +28,862 | ++ |
| + | Jav | +vertx | +28,075 | ++ |
| + | JS | +nodejs | +27,598 | ++ |
| + | Erl | +cowboy | +24,669 | ++ |
| + | C | +onion | +23,649 | ++ |
| + | Hkl | +yesod | +23,304 | ++ |
| + | JS | +express | +22,856 | +>5× | +
| + | Sca | +play-scala | +22,372 | ++ |
| + | Jav g | +rizzly-jersey | +20,550 | ++ |
| + | Py | +tornado | +20,372 | +>6× | +
| + | PHP | +phalcon | +18,481 | ++ |
| + | Grv | +grails | +18,467 | ++ |
| + | Prl | +plack | +16,647 | +>7× | +
| + | PHP | +yaf | +14,388 | ++ |
| Medium | +JS | +hapi | +11,235 | +>10× | +
| + | Jav | +play1 | +9,979 | ++ |
| + | Hkl | +snap | +9,196 | ++ |
| + | Prl | +kelp | +8,250 | ++ |
| + | Py | +flask | +8,167 | ++ |
| + | Jav | +play-java | +7,905 | ++ |
| + | Jav p | +lay-java-jpa | +7,846 | ++ |
| + | PHP | +micromvc | +7,387 | ++ |
| + | Prl | +dancer | +5,040 | +>20× | +
| + | Prl | +mojolicious | +4,371 | ++ |
| + | JS | +ringo-conv | +4,249 | ++ |
| + | Py | +django | +4,026 | ++ |
| + | PHP | +codeigniter | +3,809 | +>30× | +
| Bad | +Rby | +rails | +3,445 | ++ |
| + | Sca | +lift | +3,311 | ++ |
| + | PHP | +slim | +3,112 | ++ |
| + | PHP | +kohana | +2,378 | +>40× | +
| + | PHP | +silex | +2,364 | ++ |
| Very Bad | +PHP | +laravel | +1,639 | +>60× | +
| + | PHP | +phreeze | +1,410 | ++ |
| + | PHP | +lithium | +1,410 | ++ |
| + | PHP | +fuel | +1,410 | ++ |
| + | PHP | +cake | +1,287 | +>80× | +
| + | PHP | +symfony2 | +879 | +>100× | +
| + | C# | +aspnet-mvc | +871 | ++ |
| + | Rby | +sinatra | +561 | +>200× | +
| + | C# | +servicestack | +51 | ++ |
| + | Dar | +dart | +0 | ++ |
| + | C# | +nancy | +0 | ++ |
| + | Prl | +web-simple | +0 | ++ |
These are manually made clusters. But you get the idea. Certainly, some framework could jump between two different clusters. So this is something to remember. But as always, the order of magnitude is certainly mostly right.
+Now, how to objectively measure expressiveness?
+RedMonk had a very good idea to find an objective (while imprecise) measure of each language expressiveness. Read this article for details.
+After filtering languages suitable for web development, we end up with some clusters:
+| Cluster | +Languages | +
|---|---|
| Excellent | +Coffeescript, Clojure, Haskell | +
| Very Good | +Racket, Groovy, R, Scala, OCamL, F♯, Erlang, Lisp, Go | +
| Medium | +Perl, Python, Objective-C, Scheme, Tcl, Ruby | +
| Bad | +Lua, Fortran (free-format), PHP, Java, C++, C♯ | +
| Very Bad | +Assembly, C, Javascript, | +
Unfortunately there is no information about dart. So I simply give a very fast look at the syntax. As it looked a lot like javascript and js is quite low. I decided to put it close to java.
+Also an important remark, javascript score very badly here while coffeescript (compiling to js) score “excellent”. So if you intend to use a javascript framework but only with coffescript that should change substantially the score. As I don’t believe it is the standard. Javascript oriented framework score very badly regarding expressiveness.
+| Cluster | +Language | +Framework | +
|---|---|---|
| Excellent | +Clj | +luminus | +
| + | Clj | +http-kit | +
| + | Clj | +compojure | +
| + | Hkl | +snap | +
| + | Hkl | +yesod | +
| Very Good | +Erl | +elli | +
| + | Erl | +cowboy | +
| + | Go | +go | +
| + | Go | +revel | +
| + | Grv | +grails | +
| + | Sca | +lift | +
| + | Sca | +finagle | +
| + | Sca | +scalatra | +
| + | Sca | +play-scala | +
| + | Sca | +play-slick | +
| + | Sca | +unfiltered | +
| Medium | +Prl | +kelp | +
| + | Prl | +plack | +
| + | Prl | +dancer | +
| + | Prl | +web-simple | +
| + | Prl | +mojolicious | +
| + | Py | +flask | +
| + | Py | +django | +
| + | Py | +tornado | +
| + | Rby | +rails | +
| + | Rby | +sinatra | +
| Bad | +C# | +nancy | +
| + | C# | +aspnet-mvc | +
| + | C# | +servicestack | +
| + | C++ | +cpoll-pool | +
| + | C++ | +cpoll-cppsp | +
| + | Dar | +dart | +
| + | Jav | +play1 | +
| + | Jav | +vertx | +
| + | Jav | +gemini | +
| + | Jav | +spring | +
| + | Jav | +wicket | +
| + | Jav | +servlet | +
| + | Jav | +tapestry | +
| + | Jav | +play-java | +
| + | Jav | +dropwizard | +
| + | Jav | +rest-express | +
| + | Jav | +play-java-jpa | +
| + | Jav | +grizzly-jersey | +
| + | Lua | +openresty | +
| + | PHP | +php | +
| + | PHP | +yaf | +
| + | PHP | +cake | +
| + | PHP | +fuel | +
| + | PHP | +slim | +
| + | PHP | +silex | +
| + | PHP | +kohana | +
| + | PHP | +laravel | +
| + | PHP | +lithium | +
| + | PHP | +phalcon | +
| + | PHP | +phreeze | +
| + | PHP | +micromvc | +
| + | PHP | +symfony2 | +
| + | PHP | +codeigniter | +
| Very Bad | +C | +onion | +
| + | JS | +hapi | +
| + | JS | +ringo | +
| + | JS | +nodejs | +
| + | JS | +express | +
| + | JS | +ringo-conv | +
I couldn’t find any complete study to give the number of bug relatively to each framework/language.
+But one thing I saw from experience is the more powerful the type system the safest your application is. While the type system doesn’t remove completely the need to test your application a very good type system tend to remove complete classes of bug.
+Typically, not using pointer help to reduce the number of bugs due to bad references. Also, using a garbage collector, reduce greatly the probability to access unallocated space.
+![Static Type Properties from [James IRY Blog][typesanalysis]](/Scratch/img/blog/Rational-Web-Framework-Choice/languagesafety.png)
+From my point of view, robustness is mostly identical to safety.
+Here are the clusters:
+| Excellent | +Haskell, Scheme, Erlang | +
| Very Good | +Scala, Java, Clojure | +
| Good | +Ruby, Python, Groovy, javascript, PHP | +
| Medium | +C++, C#, Perl, Objective-C, Go, C | +
So applying this to frameworks gives the following clusters:
+| Cluster | +Language | +Framework | +
|---|---|---|
| Excellent | +Erl | +elli | +
| + | Erl | +cowboy | +
| + | Hkl | +snap | +
| + | Hkl | +yesod | +
| Very Good | +Clj | +luminus | +
| + | Clj | +http-kit | +
| + | Clj | +compojure | +
| + | Jav | +play1 | +
| + | Jav | +vertx | +
| + | Jav | +gemini | +
| + | Jav | +spring | +
| + | Jav | +wicket | +
| + | Jav | +servlet | +
| + | Jav | +tapestry | +
| + | Jav | +play-java | +
| + | Jav | +dropwizard | +
| + | Jav | +rest-express | +
| + | Jav | +play-java-jpa | +
| + | Jav | +grizzly-jersey | +
| + | Sca | +lift | +
| + | Sca | +finagle | +
| + | Sca | +scalatra | +
| + | Sca | +play-scala | +
| + | Sca | +play-slick | +
| + | Sca | +unfiltered | +
| Good | +Grv | +grails | +
| + | JS | +hapi | +
| + | JS | +ringo | +
| + | JS | +nodejs | +
| + | JS | +express | +
| + | JS | +ringo-conv | +
| + | Lua | +openresty | +
| + | PHP | +php | +
| + | PHP | +yaf | +
| + | PHP | +cake | +
| + | PHP | +fuel | +
| + | PHP | +slim | +
| + | PHP | +silex | +
| + | PHP | +kohana | +
| + | PHP | +laravel | +
| + | PHP | +lithium | +
| + | PHP | +phalcon | +
| + | PHP | +phreeze | +
| + | PHP | +micromvc | +
| + | PHP | +symfony2 | +
| + | PHP | +codeigniter | +
| + | Py | +flask | +
| + | Py | +django | +
| + | Py | +tornado | +
| + | Rby | +rails | +
| + | Rby | +sinatra | +
| Medium | +C | +onion | +
| + | C# | +nancy | +
| + | C# | +aspnet-mvc | +
| + | C# | +servicestack | +
| + | C++ | +cpoll-pool | +
| + | C++ | +cpoll-cppsp | +
| + | Dar | +dart | +
| + | Go | +go | +
| + | Go | +revel | +
| + | Prl | +kelp | +
| + | Prl | +plack | +
| + | Prl | +dancer | +
| + | Prl | +web-simple | +
| + | Prl | +mojolicious | +
For the result I initialized the table with my own needs.
+And I am quite happy it confirms my current choice. I sware I didn’t given yesod any bonus point. I tried to be the most objective and factual as possible.
+Now, it is up to you to enter your preferences.
+On each line you could change how important a feature is for you. From essential to unsignificant. Of course you could change the matrix at will.
+I just show a top 10 frameworks. In order to give a more understandable measure I provide the log of the score.
+| + | ++Excellent + | ++Very good + | ++Good + | ++Medium + | ++Bad + | ++Very bad + | ++Importance + | +
|---|---|---|---|---|---|---|---|
| +Expressiveness + | +|||||||
| +Popularity + | +|||||||
| +Efficiency + | +|||||||
| +Robustness + | +
I didn’t had the courage in explaining in what the scoring system is good. Mostly, if you use product instead of sum for the score you could use power of e for the values in the matrix. And you could see the matrix as a probability matrix (each line sum to 1). Which provide a slighly better intuition on whats going on.
+Remember only that values are exponential. Do not double an already big value for example the effect would be extreme.
+All of this is based as most as I could on objective data. The choice method seems both rather rational and classical. It is now up to you to edit the score matrix to set your needs.
+I know that in the current state there are many flaws. But it is a first system to help make a choice rationally.
+I encourage you to go further if you are not satisfied by my method.
+The source code for the matrix shouldn’t be too hard to read. Just read the source of this webpage. You could change the positionning of some frameworks if you believe I made some mistake by placing them in some bad clusters.
+So I hope this tool will help you in making your life easier.
]]>
+
+tl;dr: How I use hakyll. Abbreviations, typography corrections, multi-language, use index.html, etc…
This website is done with Hakyll.
+Hakyll can be considered as a minimal cms. But more generally it is a library helping file generation. We can view it as an advanced build system (like make).
From the user perspective I blog this way:
+A First Level Header
+====================
+
+A Second Level Header
+---------------------
+
+Who would cross the Bridge of Death must answer me
+these questions three, ere the other side he see.
+This is just a regular paragraph.
+
+Ask me the questions, bridgekeeper. I am not afraid.
+
+### Header 3
+
+> This is a blockquote.
+>
+> This is the second paragraph in the blockquote.
+>
+> ## This is an H2 in a blockquotegit push. My blog is hosted on github.Being short sighted one could reduce the role of Hakyll to:
+++create (resp. update) html file when I create (resp. change) a markdown file.
+
While it sounds easy, there are a lot of hidden details:
+The work of Hakyll is to help you with these. But let’s start with the basic concepts.
+
+For each file you create, you have to provide:
+First, let’s start with the simplest case: static files (images, fonts, etc…). Generally, you have a source directory (here is the current directory) and a destination directory _site.
The Hakyll code is:
+-- for each file in the static directory
+match "static/*" do
+ -- don't change its name nor directory
+ route idRoute
+ -- don't change its content
+ compile copyFileCompilerThis program will copy static/foo.jpg to _site/static/foo.jpg. I concede this is a bit overkill for a simple cp. Now how to write a markdown file and generate an html one?
-- for each file with md extension in the "posts/" directory
+match "posts/*.md" do
+ -- change its extension to html
+ route $ setExtension "html"
+ -- use pandoc library to compile the markdown content into html
+ compile $ pandocCompilerIf you create a file posts/foo.md, it will create a file _site/posts/foo.html.
If the file posts/foo.md contains
the file _site/posts/foo.html, will contain
But horror! _site/posts/cthulhu.html is not a complete html file. It doesn’t have any header nor footer, etc… This is where you use templates. I simply add a new directive in the compile block.
match "posts/*.md" do
+ route $ setExtension "html"
+ compile $ pandocCompiler
+ -- use the template with the current content
+ >>= loadAndApplyTemplate "templates/post.html" defaultContextNow if templates/posts.html contains:
<html>
+ <head>
+ <title>How could I get the title?</title>
+ </head>
+ <body>
+ $body$
+ </body>
+</html>our cthulhu.html contains (indentation added for readability):
<html>
+ <head>
+ <title>How could I get the title?</title>
+ </head>
+ <body>
+ <h1>Cthulhu</h1>
+ <p>ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn</p>
+ </body>
+</html>See, it’s easy But we have a problem. How could we change the title or add keywords?
+The solution is to use Contexts. For this, we first need to add some metadatas to our markdown1.
And modify slightly our template:
+ +As Sir Robin said just before dying before the Bridge of Death:
+++“That’s EASY!”
+– Sir Robin, the Not-Quite-So-Brave-As-Sir-Lancelot
+
Now that we understand the basic functionality. How to:
+That’s easy. Simply call the executable using unixFilter. Of course you’ll have to install SASS (gem install sass). And we also use compressCss to gain some space.
match "css/*" $ do
+ route $ setExtension "css"
+ compile $ getResourceString >>=
+ withItemBody (unixFilter "sass" ["--trace"]) >>=
+ return . fmap compressCssIn order to help to reference your website on the web, it is nice to add some keywords as meta datas to your html page.
+ +In order to add keywords, we could not directly use the markdown metadatas. Because, without any, there should be any meta tag in the html.
+An easy answer is to create a Context that will contains the meta tag.
-- metaKeywordContext will return a Context containing a String
+metaKeywordContext :: Context String
+-- can be reached using $metaKeywords$ in the templates
+-- Use the current item (markdown file)
+metaKeywordContext = field "metaKeywords" $ \item -> do
+ -- tags contains the content of the "tags" metadata
+ -- inside the item (understand the source)
+ tags <- getMetadataField (itemIdentifier item) "tags"
+ -- if tags is empty return an empty string
+ -- in the other case return
+ -- <meta name="keywords" content="$tags$">
+ return $ maybe "" showMetaTags tags
+ where
+ showMetaTags t = "<meta name=\"keywords\" content=\""
+ ++ t ++ "\">\n"Then we pass this Context to the loadAndApplyTemplate function:
match "posts/*.md" do
+ route $ setExtension "html"
+ compile $ pandocCompiler
+ -- use the template with the current content
+ >>= loadAndApplyTemplate "templates/post.html"
+ (defaultContext <> metaKeywordContext)++☞ Here are the imports I use for this tutorial.
++{-# LANGUAGE OverloadedStrings #-} +import Control.Monad (forM,forM_) +import Data.List (sortBy,isInfixOf) +import Data.Monoid ((<>),mconcat) +import Data.Ord (comparing) +import Hakyll +import System.Locale (defaultTimeLocale) +import System.FilePath.Posix (takeBaseName,takeDirectory + ,(</>),splitFileName)
What I mean is to use url of the form:
+http://domain.name/post/title-of-the-post/I prefer this than having to add file with .html extension. We have to change the default Hakyll route behavior. We create another function niceRoute.
-- replace a foo/bar.md by foo/bar/index.html
+-- this way the url looks like: foo/bar in most browsers
+niceRoute :: Routes
+niceRoute = customRoute createIndexRoute
+ where
+ createIndexRoute ident =
+ takeDirectory p </> takeBaseName p </> "index.html"
+ where p=toFilePath identNot too difficult. But! There might be a problem. What if there is a foo/index.html link instead of a clean foo/ in some content?
Very simple, we simply remove all /index.html to all our links.
-- replace url of the form foo/bar/index.html by foo/bar
+removeIndexHtml :: Item String -> Compiler (Item String)
+removeIndexHtml item = return $ fmap (withUrls removeIndexStr) item
+ where
+ removeIndexStr :: String -> String
+ removeIndexStr url = case splitFileName url of
+ (dir, "index.html") | isLocal dir -> dir
+ _ -> url
+ where isLocal uri = not (isInfixOf "://" uri)And we apply this filter at the end of our compilation
+match "posts/*.md" do
+ route $ niceRoute
+ compile $ pandocCompiler
+ -- use the template with the current content
+ >>= loadAndApplyTemplate "templates/post.html" defaultContext
+ >>= removeIndexHtmlCreating an archive start to be difficult. There is an example in the default Hakyll example. Unfortunately, it assumes all posts prefix their name with a date like in 2013-03-20-My-New-Post.md.
I migrated from an older blog and didn’t want to change my url. Also I prefer not to use any filename convention. Therefore, I add the date information in the metadata published. And the solution is here:
match "archive.md" $ do
+ route $ niceRoute
+ compile $ do
+ body <- getResourceBody
+ return $ renderPandoc body
+ >>= loadAndApplyTemplate "templates/archive.html" archiveCtx
+ >>= loadAndApplyTemplate "templates/base.html" defaultContext
+ >>= removeIndexHtmlWhere templates/archive.html contains
And base.html is a standard template (simpler than post.html).
archiveCtx provide a context containing an html representation of a list of posts in the metadata named posts. It will be used in the templates/archive.html file with $posts$.
archiveCtx =
+ defaultContext <>
+ metaKeywordContext <>
+ field "posts" (\_ -> postList createdFirst)postList returns an html representation of a list of posts given an Item sort function. The representation will apply a minimal template on all posts. Then it concatenate all the results. The template is post-item.html:
Here is how it is done:
+postList :: [Item String] -> Compiler [Item String]
+ -> Compiler String
+postList sortFilter = do
+ -- sorted posts
+ posts <- loadAll "post/*" >>= sortFilter
+ itemTpl <- loadBody "templates/post-item.html"
+ -- we apply the template to all post
+ -- and we concatenate the result.
+ -- list is a string
+ list <- applyTemplateList itemTpl defaultContext posts
+ return listcreatedFirst sort a list of item and put it inside Compiler context. We need to be in the Compiler context to access metadatas.
createdFirst :: [Item String] -> Compiler [Item String]
+createdFirst items = do
+ -- itemsWithTime is a list of couple (date,item)
+ itemsWithTime <- forM items $ \item -> do
+ -- getItemUTC will look for the metadata "published" or "date"
+ -- then it will try to get the date from some standard formats
+ utc <- getItemUTC defaultTimeLocale $ itemIdentifier item
+ return (utc,item)
+ -- we return a sorted item list
+ return $ map snd $ reverse $ sortBy (comparing fst) itemsWithTimeIt wasn’t so easy. But it works pretty well.
+To create an rss feed, we have to:
+We could then render the posts twice. One for html rendering and another time for rss. Remark we need to generate the rss version to create the html one.
+One of the great feature of Hakyll is to be able to save snapshots. Here is how:
+match "posts/*.md" do
+ route $ setExtension "html"
+ compile $ pandocCompiler
+ -- save a snapshot to be used later in rss generation
+ >>= saveSnapshot "content"
+ >>= loadAndApplyTemplate "templates/post.html" defaultContextNow for each post there is a snapshot named “content” associated. The snapshots are created before applying a template and after applying pandoc. Furthermore feed don’t need a source markdown file. Then we create a new file from no one. Instead of using match, we use create:
create ["feed.xml"] $ do
+ route idRoute
+ compile $ do
+ -- load all "content" snapshots of all posts
+ loadAllSnapshots "posts/*" "content"
+ -- take the latest 10
+ >>= (fmap (take 10)) . createdFirst
+ -- renderAntom feed using some configuration
+ >>= renderAtom feedConfiguration feedCtx
+ where
+ feedCtx :: Context String
+ feedCtx = defaultContext <>
+ -- $description$ will render as the post body
+ bodyField "description"The feedConfiguration contains some general informations about the feed.
feedConfiguration :: FeedConfiguration
+feedConfiguration = FeedConfiguration
+ { feedTitle = "Great Old Ones"
+ , feedDescription = "This feed provide information about Great Old Ones"
+ , feedAuthorName = "Abdul Alhazred"
+ , feedAuthorEmail = "abdul.alhazred@great-old-ones.com"
+ , feedRoot = "http://great-old-ones.com"
+ }Great idea certainly steal from nanoc (my previous blog engine)!
+As I just said, nanoc was my preceding blog engine. It is written in Ruby and as Hakyll, it is quite awesome. And one thing Ruby does more naturally than Haskell is regular expressions. I had a lot of filters in nanoc. I lost some because I don’t use them much. But I wanted to keep some. Generally, filtering the content is just a way to apply to the body a function of type String -> String.
Also we generally want prefilters (to filter the markdown) and postfilters (to filter the html after the pandoc compilation).
+Here is how I do it:
+markdownPostBehavior = do
+ route $ niceRoute
+ compile $ do
+ body <- getResourceBody
+ prefilteredText <- return $ (fmap preFilters body)
+ return $ renderPandoc prefilteredText
+ >>= applyFilter postFilters
+ >>= saveSnapshot "content"
+ >>= loadAndApplyTemplate "templates/post.html" yContext
+ >>= loadAndApplyTemplate "templates/boilerplate.html" yContext
+ >>= relativizeUrls
+ >>= removeIndexHtmlWhere
+applyFilter strfilter str = return $ (fmap $ strfilter) str
+preFilters :: String -> String
+postFilters :: String -> StringNow we have a simple way to filter the content. Let’s augment the markdown ability.
+Comparing to LaTeX, a very annoying markdown limitation is the lack of abbreviations.
+Fortunately we can filter our content. And here is the filter I use:
+abbreviationFilter :: String -> String
+abbreviationFilter = replaceAll "%[a-zA-Z0-9_]*" newnaming
+ where
+ newnaming matched = case M.lookup (tail matched) abbreviations of
+ Nothing -> matched
+ Just v -> v
+abbreviations :: Map String String
+abbreviations = M.fromList
+ [ ("html", "<span class=\"sc\">html</span>")
+ , ("css", "<span class=\"sc\">css</span>")
+ , ("svg", "<span class=\"sc\">svg</span>")
+ , ("xml", "<span class=\"sc\">xml</span>")
+ , ("xslt", "<span class=\"sc\">xslt</span>") ]It will search for all string starting by ‘%’ and it will search in the Map if there is a corresponding abbreviation. If there is one, we replace the content. Otherwise we do nothing.
Do you really believe I type
+ +each time I write LaTeX?
+Generally I write my post in English and French. And this is more difficult than it appears. For example, I need to filter the language in order to get the right list of posts. I also use some words in the templates and I want them to be translated.
+ +First I create a Map containing all translations.
+data Trad = Trad { frTrad :: String, enTrad :: String }
+
+trads :: Map String Trad
+trads = M.fromList $ map toTrad [
+ ("changeLanguage",
+ ("English"
+ , "Français"))
+ ,("switchCss",
+ ("Changer de theme"
+ ,"Change Theme"))
+ ,("socialPrivacy",
+ ("Ces liens sociaux préservent votre vie privée"
+ ,"These social sharing links preserve your privacy"))
+ ]
+ where
+ toTrad (key,(french,english)) =
+ (key, Trad { frTrad = french , enTrad = english })Then I create a context for all key:
+tradsContext :: Context a
+tradsContext = mconcat (map addTrad (M.keys trads))
+ where
+ addTrad :: String -> Context a
+ addTrad name =
+ field name $ \item -> do
+ lang <- itemLang item
+ case M.lookup name trads of
+ Just (Trad lmap) -> case M.lookup (L lang) lmap of
+ Just tr -> return tr
+ Nothing -> return ("NO TRANSLATION FOR " ++ name)
+ Nothing -> return ("NO TRANSLATION FOR " ++ name)The full code is here. And except from the main file, I use literate Haskell. This way the code should be easier to understand.
+If you want to know why I switched from nanoc:
+My preceding nanoc website was a bit too messy. So much in fact, that the dependency system recompiled the entire website for any change.
+So I had to do something about it. I had two choices:
+I added too much functionalities in my nanoc system. Starting from scratch (almost) remove efficiently a lot of unused crap.
+So far I am very happy with the switch. A complete build is about 4x faster. I didn’t broke the dependency system this time. As soon as I modify and save the markdown source, I can reload the page in the browser.
+I removed a lot of feature thought. Some of them will be difficult to achieve with Hakyll. A typical example:
+In nanoc I could take a file like this as source:
+ +And it will create a file foo.hs which could then be downloaded.
<h1>Title</h1>
+
+<p>content</p>
+
+<a href="code/foo.hs">Download foo.hs</a>
+<pre><code>main = putStrLn "Cthulhu!"</code></pre>We could also add the metadatas in an external file (foo.md.metadata).↩
+
+tl;dr: Default share buttons track your users, aren’t uniform with your design, use computer ressources and slow down your web page loading.
+Do it right. Use static links instead.
+If you don’t want to read, just copy/paste this in your html:
+<div id="sociallinks">
+ <a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Tweet this</a> -
+ <a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Like this</a> -
+ <a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Share on G+</a>
+</div>
+<script>
+(function(){window.addEventListener("DOMContentLoaded",function(){
+ var url=document.location;
+ var links=document.getElementById("sociallinks")
+ .getElementsByTagName('a');
+ for (var i=0;i!=links.length;i++){
+ links[i].setAttribute("href",
+ links[i].href.replace('$url$',url));}})})();
+</script>Ever been on a website and want to tweet about it? Fortunately, the website might have a button to help you. But do you really know what this button do?
+The “Like”, “Tweet” and “+1” buttons will call a javascript. It will get access to your cookies. It helps the provider of the button to know who you are.
+In plain English, the “+1” button will inform Google you are visiting the website, even if you don’t click on “+1”. The same is true for the “like” button for facebook and the “tweet this” button for twitter.
+The problem is not only a privacy issue. In fact (sadly imho) this isn’t an issue for most people. These button consume computer ressources. Far more than a simple link. It thus slow down a bit the computer and consume energy. These button could also slow down the rendering of your web page.
+Another aspect is their design. Their look and feel is mostly imposed by the provider.
+The most problematic aspect in my opinion is to use a third party js on your website. What if tomorrow twitter update their tweet button? If the upgrade break something for only a minority of people, they won’t fix it. This could occur anytime without any notification. They just have to add a document.write in their js you call asynchronously and BAM! Your website is just an empty blank page. And as you call many external ressources, it can be very difficult to find the origin of the problem.
Using social network buttons:
+I will provide you two solutions with the following properties:
+Solution 1 (no js):
+<a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Tweet this</a>
+
+<a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Like this</a>
+
+<a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Share on G+</a>But you have to replace $url$ by the current url.
Solution 2 (Just copy/paste):
+If you don’t want to write the url yourself, you could use some minimal js:
+<div id="sociallinks">
+ <a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Tweet this</a> -
+ <a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Like this</a> -
+ <a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Share on G+</a>
+</div>
+<script>
+(function(){window.addEventListener("DOMContentLoaded",function(){
+ var url=document.location;
+ var links=document.getElementById("sociallinks")
+ .getElementsByTagName('a');
+ for (var i=0;i!=links.length;i++){
+ links[i].setAttribute("href",
+ links[i].href.replace('$url$',url));}})})();
+</script>Here is the result:
+If you don’t want just text but nice icons. You have many choices:
+<img src="..."/> in the links.As the first solution is pretty straightforward, I’ll explain the second one.
+@font-face
+ font-family: 'social'
+ src: url('fonts/social_font.ttf') format('truetype')
+ font-weight: normal
+ font-style: normal
+.social
+ font-family: socialNow add this to your html:
+Solution 1 (without js):
+<a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">t</a>
+·
+<a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">`</a>
+·
+<a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">g</a>Solution 2 (same with a bit more js):
+<div id="sociallinksunicode">
+<a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">t</a>
+·
+<a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">`</a>
+·
+<a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">g</a>
+</div>
+<script>
+(function(){window.addEventListener("DOMContentLoaded",function(){
+ var url=document.location;
+ var links=document.getElementById("sociallinksunicode")
+ .getElementsByTagName('a');
+ for (var i=0;i!=links.length;i++){
+ links[i].setAttribute("href",
+ links[i].href.replace('$url$',url));}})})();
+</script>Here is the result:
+ps: On my personal website I continue to use Google analytics. Therefore, Google (and only Google, not facebook nor twitter) can track you here. But I might change this in the future.
]]>Yesterday I was happy to make a presentation about Category Theory at Riviera Scala Clojure Meetup (note I used only Haskell for my examples).
+ +If you don't want to read them through an HTML presentations framework or downloading a big PDF +just continue to read as a standard web page. +
+ + + + + +
+Recent Math Field
1942-45, Samuel Eilenberg & Saunders Mac Lane
Certainly one of the more abstract branches of math
+
+★: When is one thing equal to some other thing?, Barry Mazur, 2007
☆: Physics, Topology, Logic and Computation: A Rosetta Stone, John C. Baez, Mike Stay, 2009
+
+Programming is doing Math
+Strong relations between type theory and category theory.
+Not convinced?
Certainly a vocabulary problem.
One of the goal of Category Theory is to create a homogeneous vocabulary between different disciplines.
+
+Math vocabulary used in this presentation:
+++Category, Morphism, Associativity, Preorder, Functor, Endofunctor, Categorial property, Commutative diagram, Isomorph, Initial, Dual, Monoid, Natural transformation, Monad, Klesli arrows, κατα-morphism, ...
+
+| +Mathematician + | +Programmer + |
|---|---|
| +Morphism + | +Arrow + |
| +Monoid + | +String-like + |
| +Preorder + | +Acyclic graph + |
| +Isomorph + | +The same + |
| +Natural transformation + | +rearrangement function + |
| +Funny Category + | +LOLCat + |
+
+\(\ob{\mathcal{C}}\) is a collection
+
+
+\(A\) and \(B\) objects of \(\C\)
+\(\hom{A,B}\) is a collection of morphisms
+\(f:A→B\) denote the fact \(f\) belongs to \(\hom{A,B}\)
\(\hom{\C}\) the collection of all morphisms of \(\C\)
+Composition (∘): associate to each couple \(f:A→B, g:B→C\) + $$g∘f:A\rightarrow C$$ +
+
+for each object \(X\), there is an \(\id_X:X→X\),
+such that for each \(f:A→B\):
+Composition is associative:
+
+Two path with the same source and destination are equal.
+
+
+
+\(\ob{\C},\hom{\C}\) fixed, is there a valid ∘?
+
+
+
+
+
+
+
+(.) )
+(++) "" ++ u = u = u ++ "" (u ++ v) ++ w = u ++ (v ++ w)
+
+
+Each Monoid \((M,e,⊙): \ob{M}=\{∙\},\hom{M}=M,\circ = ⊙\)
+Only one object.
+Examples:
+(Integer,0,+), (Integer,1,*),
+(Strings,"",++), for each a, ([a],[],++)
+At most one morphism between two objects.
+ +
+
+Any set \(E: \ob{E}=E, \hom{x,y}=\{x\} ⇔ x=y \)
+Only identities
+ isomorphism: \(f:A→B\) which can be "undone" i.e.
\(∃g:B→A\), \(g∘f=id_A\) & \(f∘g=id_B\)
in this case, \(A\) & \(B\) are isomorphic.
A≌B means A and B are essentially the same.
In Category Theory, = is in fact mostly ≌.
For example in commutative diagrams.
+
+
+An endofunctor for \(\C\) is a functor \(F:\C→\C\).
+
+
+
+Categories and functors form a category: \(\Cat\)
+Category \(\Hask\):
+ +
+
+(.) Haskell function composition
+Forget glitches because of undefined.
Put normal function inside a container. Ex: list, trees...
+
+
+
Haskell functor can be seen as boxes containing all Haskell types and functions. +Haskell types look like a fractal:
+ +
+Haskell functor can be seen as boxes containing all Haskell types and functions. +Haskell types look like a fractal:
+ +
+Haskell functor can be seen as boxes containing all Haskell types and functions. +Haskell types look like a fractal:
+ +
+
+Let \(F\) and \(G\) be two functors from \(\C\) to \(\D\).
+ A natural transformation: familly η ; \(η_X\in\hom{\D}\) for \(X\in\ob{\C}\) s.t.
ex: between Haskell functors; F a -> G a
Rearragement functions only.
data List a = Nil | Cons a (List a)
+toList :: [a] -> List a
+toList [] = Nil
+toList (x:xs) = Cons x (toList xs)toList is a natural transformation. It is also a morphism from [] to List in the Category of \(\Hask\) endofunctors.
+
+data List a = Nil | Cons a (List a)
+toHList :: List a -> [a]
+toHList Nil = []
+toHList (Cons x xs) = x:toHList xstoHList is a natural transformation. It is also a morphism from List to [] in the Category of \(\Hask\) endofunctors.
+ toList . toHList = id & toHList . toList = id [] & List are isomorph. toMaybe :: [a] -> Maybe a
+toMaybe [] = Nothing
+toMaybe (x:xs) = Just xtoMaybe is a natural transformation. It is also a morphism from [] to Maybe in the Category of \(\Hask\) endofunctors.
+
+mToList :: Maybe a -> [a]
+mToList Nothing = []
+mToList Just x = [x]toMaybe is a natural transformation. It is also a morphism from [] to Maybe in the Category of \(\Hask\) endofunctors.
+ Bool lists longer than 1. fold
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ 
+tl;dr: My short and highly subjective feelings about the programming languages I used.
+BASIC
+The language of my firsts programs! I was about 10, with an MO5 and Amstrad CPC 6128 and even with my Atari STe. This is the language of GOTOs. Ô nostalgia. Unfortunately this might be the only interesting part of this language.
Today this language is obsolescent. It is not even good to learn programming. I know some compiler exists now. But this is not enough to try to learn it.
+ +I also remember I copied some game source code from some magazine. Most lines were like:
+ +What a pleasure!
+
+I was about 10 when I played with logo to draw things on a screen.
+I remember the Bach’s music while the program loaded.
+At that time we had to load the program into the memory using tapes. This one was a rare one. It didn’t made an awfull ‘Krrrkrr cssssss krrr’ noise.
+Some years after, I used it to learn programming to my college student. It was a really good first language. Making fractals is like a game for children.
+Here is the code to draw the dragon fractal:
+HIDETURTLE
+
+PENUP
+SETXY -200 0
+RIGHT 90
+PENDOWN
+
+to dragon :degree :size
+ setpensize 1
+ if :size>5 [setpensize 2]
+ if :size>10 [setpensize 3]
+ if :size>20 [setpensize 4]
+ if :size>40 [setpensize 5]
+ ifelse :degree=0 [
+ fd :size
+ ][
+ left 45 dragon (:degree-1) (size/4)
+ right 90 dragon (:degree-1) (size/2)
+ left 90 dragon (:degree-1) (size/4)
+ right 45
+ ]
+end
+
+dragon 6 3000The eternal second.
+I made my firsts real serious program with Pascal. I must confess I find it inferior to C. I made graph algorithms, sort algorithms even some IA (genetic) algorithms. In the end I prefer C.
+
+The pointer’s language.
+Le programming language.
+Once you understand loops and recursion, it is time to do serious things. If you want to make good quality code, knowing C is almost mandatory.
+This language is close to the machine language. So much, there is (mostly) a linear relation between the size of your code and the size of the compiled one.
+In short, each time you write a C instruction there won’t be anything strange that will occurs, like starting a long algorithm behind the scene.
+While close to the machine, C keep sufficient abstractions to be fun.
I made a lot of program with it. From sort algorithms to AI ones (SAT3), system, network programming, etc… It is a very useful language that will help you understand how things works on your computer. Most modern computer language hide a lot of informations on what occurs. This is not the case with C.
The “super clean” one.
+I liked ADA. I must confess I didn’t used it a lot. May be one day I will try it again. I was impressed by asynchronous programming with it. What you need to know is this old language had certainly inspired most new object oriented languages.
+Until here I just described imperative languages without any object notion.
+More clearly, the language didn’t helped you to structure your program.
+In order to limit the number of bugs, particularly for huge programs, we started to think about how to organize computer programs. In the end, from the imperative language culture, it produced the Object Oriented programming (OOP). Beware, the Object Oriented programming isn’t a miracle. Proof? How many bug free software do you use? Furthermore, OOP doesn’t fit all problems. But to make a bank application, an application which help to manage stock, clients or text archives or more generally an information system, the OOP is not so bad.
+Then Object Oriented Languages appeared everywhere.
+
+The ugly
+Industry wanted an Object Oriented Language without losing all their old C code. Solution, keep C and add an Object layer on it. My main concern about C++ is: it does too many things. I appreciated multiple inheritance and templates. In reality I liked a lot C++ while I was working alone. I used it to write DEES my main thesis software. My only concern was about a lack in the STL. In the doc, one could use String<T>. But in reality, T had to be only char or char16. Then I had to reduce my alphabet to 216 letters. Except for some application, the alphabet must be far larger than that. To conclude, I’d say, C++ is very good if you work alone or with a fixed subset of its features.
+Yes, it is a really nice language. Full object in mind. Far cleaner than C++. But it isn’t so popular. Behind C++ there is a large community to help new users and to write libraries. Furthermore, I preferred working with C++. When I learned Eiffel, I programmed a lot with C and liked its syntax.
+
+The first time I heard about Java it was le Grail!
+Perfect portability, your program will work on all platform. The language helps limit mistakes, and force you to use good programming habits. But…
+But It is extremely verbose. Many limitations are quite boring if you know what you’re doing.
+For example, there is no multiple inheritance. Generally it is a coherent choice when there are a way to compensate. In Java, there are interfaces for this. Except, interfaces can only add methods to a class. You cannot add any attribute to a class except by subclassing. I really lacked this feature.
+I made a GUI using Java Swing and I created my own notification system between different element of the GUI. In the beginning I only needed to send notification one to one. After some time, I wanted to send one to many notifications. I had to make a bunch of copy/paste inside all my subclasses! Copy/paste are exactly what should be avoided the most by object oriented languages.
+Another thing: threads. I was forced to make my own thread management system to avoid locks and send notifications between threads (wait the end of this thread, …). At that time I used Java 1.5. This problem should have been solved with Java 1.6. I wish it is the case, but lacking such an essential feature for a language was very bad.
+In the same idea, it was very long to wait for the “foreach” loops.
+After my experience, I don’t recommend Java. Portability does not worth this price.
+GUI portability means mediocre experience on all platforms. Any system it might be (wxWidget, QT, etc…).
+The Java ideology is “closed”. But it resolve a big problem. It helps medium to low quality developers to work in team without the ability to make too much harm to the product. A good programmer will be able to make very interesting things with it thought. Please note I didn’t say Java programmer are bad programmer.
+
+The language I learned and used only to make application on Apple© platform. I learned Objective-C just after Python. It was hard to do it. At first I didn’t liked the syntax and many other details. But it is this kind of language the more you use, the more you like. In fact, Objective-C is a simple language, but associated with the Cocoa framework it is a really good tool. Cocoa is very different to other framework I used before. I find many of its idea extremely good. Both simple and efficient. It might seems like small details on paper, but once you start using it, it makes all the difference.
+Even if Objective-C is a relatively low level language. Its dynamic typing ability make it very good for GUI programming. I recommend to continue working with this language. In the end you’ll certainly find it better than expected.
+
+This small script language that we used all to make our website in the time of animated gifs.
+Nice but no more. Apparently there were a lot of progress since PHP5. Maybe one day I’ll use it again. But behind it, this language has a “script kiddies only” reputation. Also long history of easy to make security holes.
+In reality PHP is just behind C for the abstraction level. Therefore it has a lot of organisation problems and make it easier to create bugs. For web applications it is a real problem.
+PHP remains for me the SQL injection language. I made a bit of PHP not so long ago, and it was a pain to protect my application to SQL injection. Yep, I didn’t found any standard library to make this, but I didn’t searched a lot.
+
+Revelation!
+When you were used to work with compiled languages (C++, Java) and you start learning Python, it’s like a punch in the face. Programming like it always should have been. Everything is natural, it’s magic. Yes, as good as this. But something so good must have some drawback.
+And yes, like all interpreted languages, Python is slow. Beware, no just a bit slow like 2 or 3 times slower than C. (like Java for example). No, really slow, about 10 to 20 times slower than C. Argh… Note it is completely usable for many things.
+If you have to “filter” some files and the filter is not too complicated awk is the ideal language to do this. For example, if you want to know which words in a text file are most used. I used it to modify hundreds of XML files in an easier manner than XSLT.
+Perl is magic, but the syntax is so hideous nobody can like to work in an environment with many different person in Perl. Or at least, all other collaborators must be excellent programmers. A great feature of perl is its integration with regular expression in its syntax:
+ +This program will replace every toto by titi inside the $var variable. The Perl code is often very compact and generally unreadable. But it is a language good to know. It is a kind of awk under steroids.
Ruby is a very good language. It is often compared (opposed ?) to Python. There are the regular expression operators Perl inside the langage. But the syntax is extremely clear, like in Python. Many feature were inspired by functional programming (as in Python). I used it a lot. It is the worst language I know in term of efficiency. This is the language that lose almost all benchmarks. But it is the perfect tool for prototypes. If you want to make a website prototype, RoR (Ruby on Rails) is certainly one of the best system known to mankind. From idea to realisation, few time will occur. Make this site work for thousands of people, will, on the other hand, certainly require a lot of optimisations.
+One of the greatest Ruby feature is its ability to make the program extremely readable. It is very close to natural language. On the other hand, I found the Object Oriented layer a bit disappointing. The fact there is no real “class variable” but only “tree class variable” for example.
+Considering the community, the ruby one feels closer to the creative than the engineer. I am under the impression designer tends to use Ruby instead of Python.
+It is the good surprise. During years, javascript was considered as an annoying web experience language. In reality, javascript has many really good qualities. Particularly, it is easy to pass a function in parameter and to create anonymous functions. Recently, javascript became far faster than before and many frameworks and libraries appears:
+Particularly with jQuery we can chain functions. It is very nice to use. As I said, this is a good surprise. Javascript was chosen by chance as the script inside your navigator. Instead of the java inspired syntax, everything else is very good. In order to compensate the syntax, you can use CoffeeScript.
+I learned CamL during the college. It was really interesting. Functional programming is very different to imperative programming (most of popular languages). I had good mathematic intuitions to use this language. But I must confess I never used it for something serious.
+I believe I will still learning this language in many years. I must say it is a pleasure. Generally it takes me no more than some hours to some days to learn a new programming language. Concerning Haskell, this is very different. To master Haskell you need to understand very abstract concepts. Monads and Arrows are some of them. I didn’t understood them before I read some scientific paper. Many week will be necessary to master it perfectly (if someone does). Also the community is very friendly and nice. There is no “LOL! URAN00B! RTFM!” And no concession has been made to make this language more popular (I’m looking at you C++, Java and Javascript). This langage remain pure (I know there are two meaning).
+Concerning making real product with Haskell. In fact, Haskell is very efficient concerning code change. Refactoring code is incredibly easy with Haskell. And in the same time, the Haskell type system helps to make your product bug free.
+Technically this language is close to perfection. But it has some major problems:
+On the other hand, knowing Haskell will help you learn a lot of thing about programming in general. You should at least take a look. I made an Haskell introduction if you are curious.
+Metapost is a language to program drawings. What make metapost very good? It contains a linear solver. This is really useful to draw things. For example if you write:
+ +It will place the point AA between the point A and B. More precisely at the barycenter (2xA + B)/3.
This second example, will place the point X at the intersection of the two segments AB and CD.
This feature is very helpful, and not only to draw things. Most programming language should think about adding it.
+Yes, zsh is a shell. But it is also a script language very well suited to file management. For now, it is the best shell I used. I prefer zsh to bash.
+I never made something serious with Prolog, but I really loved to use and learn it. I had the chance to learn Prolog with Alain Colmerauer himself. This language try to resolve constraints as much as it can. It has a magic feeling when you use it. We only write constraints, we never put order. A bit like functional programming but far more powerful.
+Many languages and framework remains to be learnt and tried. Actually I believe I will stay a while with Haskell. Maybe tomorrow I will look at LISP, Scala or Erlang. I also certainly look at clojure to make web application.
+Tell me if you have any other experience with these programming languages. Of course, my feelings are highly subjectives. But I used all of these languages.
+[STL]: Standard Tempate Library [GUI]: Graphic User Interface
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ When you click on this logo:
+
You have the capability to subscribe to my RSS flux. But what it is all about?
+You can visit what is rss or even better look this cool video: RSS explained.
+It is an easy way to aggregate all the update made on websites you like in a single place. You’ll never have to surf many website to see if there is news on a website.
+To begin, you must choose an RSS client called aggregator. There is many online clients: website which will present the news in a fancy way.
+Personally I use Netvibes. I tried a bunch, and it is by far the best - In My Humble Opinion.
+Of course Google has a client named Google Reader. It is great for content you never want to forgot some article. It is not really useful when you have to handle flux generating many news per day.
+Once you have chosen your aggregator, you only have to subscribe to websites you like. Do do this, you only have to click on the RSS icon in the top bar of your navigator. Or generally a nice icon is shown into the page you’re reading.
+Now, you’ll only have to use your RSS client. And you’ll see all news on all subscribed websites. There is no more need to surf many websites. All news which interest you are in the same place.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ 
YAquaBubbles is a QuartzComposer Screensaver. It was one of my first try but the result was nice.
+ +
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ 
YClock is a nice clock screensaver. It has three themes: white, black and red. It is based on a QuartzComposition and with some little Objective-C code to handle gently the frame per second.
+ +
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Easy, Secure and Portable way to manage your web passwords.
+Here done in elm:
Remember only one strong password. And the rest follow.
+Here you can find:
+I’ll soon release an iPhone application.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ 
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ One word to explain why there is some validation errors.
+I wanted to use box-shadows and border-radius.
Then here I prefered pragmatism against dogmatism.
+Using these properties broke my validation but work really well in the two most recent and main browsers (Safari 4 and Firefox 3.5 at the time I’m writing these lines). If you don’t use these browser the page is correctly displayed but not with all the ‘eyecandy’ effects.
+I believed in the benefits of CSS validation, this is why there is alway the CSS validation link on my pages. And all CSS validate except for properities beginning by -moz and -webkit.
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ | name | +Yann Esposito | +
| + | |
| port | +(+33)650845271 | +
| address | +Bât 9, Résidence Saint Marc | +
| + | 591, avenue Jean Aicard | +
| + | 06700, Saint Laurent du Var | +
| 2016 | +→ | ++ | Clojure Software Engineer for Cisco (Threatgrid), Remote | +
| 2013 | +→ | +2016 | +Machine Learning Scientist & Software Engineer at Vigiglobe, Sophia Antipolis, France | +
| 2010 | +→ | ++ | Co-Founder of GridPocket, Sophia Antipolis, France | +
| 2007 | +→ | +2013 | +AirFrance, Sophia Antipolis, France | +
| 10/2006 | +→ | +3/2007 | +Post Ph.D., Hubert Curien Laboratory, St-Etienne, France | +
| 10/2004 | +→ | +9/2006 | +ATER (College Degree Teach & Research), Marseille, France | +
| 10/2001 | +→ | +9/2004 | +University Monitor (College Degree Teach & Research), Marseille, France | +
| 1995 | +→ | +2000 | +Miscellaneous summer jobs | +
| 2004 | +CS Ph.D. in Machine Learning at Université de Provence | +
| 2001 | +D.E.A. (Equivalent to Master in Computer science) | +
| 2000 | +Maîtrise in Computer Science | +
| 1999 | +Licence in Computer Science | +
| 1998 | +DEUG MIAS (Math) | +
| 1995 | +BAC S (Math) | +
| International Journal | +[Fundamenta Informaticæ, 2008] | +
| + | [Pattern Recognition, 2004] | +
| Internation Conferences | +[ECML 2008] [ICGI 2006] [COLT 2006] | +
| + | [COLT 2004] [ICALP 2003] [ICGI 2002] | +
| National Journal | +[JEDAI 2002] | +
| National Conferences | +[CAp’06] [CAp’04] [CAp’03] | +
I am French with a Post Ph.D in Machine Learning1. Furthermore I love web programming and design.
+I am currently working remotely for Cisco Security team as a Clojure Software Engineer.
+Previously I worked for Vigiglobe. The first six months I worked with node.js (API/MongoDB/Web). Then we upgraded our stack to Clojure, Haskell, Mesos, Kafka, Druid, etc… At that time we were two to make all technical decisions. In the end we made a real time analytics of social media content on a scalable architecture. Actually our architecture is able to manage (Aggregation & Machine Learning) thousands of messages per second.2 In particular, I’ve written an Haskell twitter stream absorber able to handle thousands of tweets per seconds. And I coded myself a real time sentiment analysis module taking algebraic properties into account to optimize its efficiency.
During my Ph.D. I made a C++ program (github3 and resume4). I coded most of standard HMM learning algorithms. I developed an algorithm which I invented during my Ph.D. which use some operational optimization algorithm. During this period I published articles in international conferences and I taught Computer Science to college students.
At the Hubert Curien Laboratory I made my post Ph.D. I developed a scientific application in Java/applet/JWS that should be used by biologists. The code has been updated a bit since my 6 month post Ph.D5.
I worked in the web industry for Airfrance. My work environment was quite heterogeneous. From shell scripting to manage huge amount of data, web design and production environment.
I worked for GridPocket (I am a co-founder). This is a French startup specialized in Electric Grid. I created a private6 web application.
I’ve also written an iOS application to manage passwords7.
I am the author of some quite popular blog posts8.
For an almost exhaustive list of my projects, you could check my github account: github.com/yogsototh
+ +| Languages | +Haskell, Clojure, Javascript, | +
| + | scheme, C, camL, C++, Ruby, Perl, Java, Python, PHP | +
| Web frontend | +elm, Clojurescript, Reagent, Angular.js, sass, etc… | +
| Web frameworks | +compojure-api, Yesod, servant, actionhero | +
| ML Tools | +weka, SVMlight | +
| Stream Computing | +kafka, druid, storm (with clojure) | +
| UNIX | +Shell scripts (zsh, bash), awk, , ConTeXt, metapost | +
| VCS | +git, Bazaar (DCVS), subversion (svn), CVS | +
| Mac/iOS | +Objective-C Cocoa (Mac & iOS), Dahsboard widget, | +
| + | Quartz Composer | +
| Product | +Security Threat Management | +
| Role | +Clojure Software Engineer | +
| Product | +Scalable Real Time Social Media Analytics | +
| + | Sentiment Analysis | +
| + | Many client side web applications (Angular.js & reagent) | +
| Role | +Machine Learning Scientist | +
| + | (fast sentiment analysis, learning protocols, etc..) | +
| + | Full stack engineer (backend to frontend architecture) | +
| Keywords | +Clojure, Haskell, node.js, reagent, Angular.js, Stream computing | +
Sophia Antipolis, France
+| Product | +Two API server (one for client, another for administration) | +
| + | A private client side web application | +
| + | An iPhone Application | +
| + | Some Linux boxes to send data to the servers | +
| + | A Linux driver | +
| Role | +Full technical responsibilities | +
| Keywords | +Ruby, REST, JSON, HTML, CSS, Javascript, AJAX, | +
| + | jQuery, Objective-C, ASIHTTPRequest, CorePlot, CoreData, C | +
Sophia Antipolis, France
+| Role | +In charge of the Airfrance CMS for their website. | +
| Keywords | +TeamSite, Perl, XML, XHTML, CSS, javascript, JSP, | +
| + | Unix (Solaris/Linux), Bazaar | +
Université Jean Monet, Laboratoire Hubert Curien, Saint-Etienne
+| Product | +SeDiL | +
| Role | +Java Developer | +
| Research | +Similarity measure between strings or XML trees | +
| Contact | ++ |
| Keywords | +UML, Java 1.5, Swing, Java 2D, Java Web Start, Applet, | +
| + | subversion, XML, XHTML, PHP | +
Details:
+++Java application: 11 000 lines with javadoc
+Main functionalities
++
+ +- learn edit matrices
+- compute edit distances between trees or strings
+- visualize trees or sequences (JAVA 2D)
+- classification using K means
+- Generate random tree couple from an edit distance matrice
+
Research & Teacher, Université de Provence, Marseille
+teach 1/2, research 1/6, C++ development 1/3
+DEES ; a C++ software
+++7500 lines of C++ code, 10.000 with comments
+Main functionalities:
++
+- Mulitiplicity Automata, HMM & PDA Inference,
+- Baum Welch & Viterbi Algorithms,
+- GraphViz export,
+- String Generation from many Models,
++ +
++ +Languages +C++ ++ +API +STL ++ + +Environment +Linux (Debian) & Windows XP +
Université de Provence, Marseille
+teach 1/3, research 1/3, C++ Development 1/3
+Creation of DEES (see preceeding entry).
+ +| 2004 | +Ph.D. degree in Machine Learning | +
| 2001 | +D.E.A. in Computer Science (equivalent to master) | +
| 2000 | +Maîtrise d’Informatique | +
| 1999 | +Licence in Computer Science | +
| 1998 | +DEUG MIAS (math) | +
| 1995 | +BAC S (math) | +
| Journals | +[Fundamenta Inforamticæ vol.86 2008][Pattern Recognition, 2004] | +
| Conferences | +[ECML 2008] [COLT 2006] [ICGI 2006][COLT 2004] [ICALP 2003] [ICGI 2002] | +
| Workshop | +[TAGI05] | +
| Journals | +[JEDAI, 2003] | +
| Conferences | +[CAP 2006] [CAP 2004] [CAP 2003] | +
| Thesis | +[Université de Provence 2004] | +
Most of my latest programming activities are publicly available at github.com/yogsototh
+holy-projecthuman-readable-durationwai-middleware-caching-lruwai-middleware-caching-rediswai-middleware-caching
Mainly an iOS application:
+ +I’ve done fully the website from scratch. Also there are some javascript implementation of YPassword method:
++++
+- a Mac OS X dashboard widget,
+- a Cappuccino Web application,
+- a jQuery Web application,
+- a command line tool,
+- an Applescript helper
+
Made a protocol similar to TOR for student.
+You could find even more information by looking at:
+
http://yannesposito.comhttp://github.com/yogsotothTo be more precise in Grammatical Inference↩
http://labh-curien.univ-st-etienne.fr/SEDiL/faq.php?lang=en (I like to believe I became a better designer ☺)↩
Sorry the code is private I can’t show it :(.↩
@ yann.esposito@gmail.com
+ @yogsototh
+ yogsototh
+ yogsototh
+ yogsototh
+ yogsototh
ADA: DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
Je suis un passionné. Passionné par :
+Mais avant tout j’adore apprendre. Par exemple, j’ai appris de nombreux langages de programmation: Haskell, Clojure, javascript, C, C++, Objective-C, Python, Ruby, Java, Perl, awk, bash, zsh, LaTeX, metapost, camL, Scheme…
+ +
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Il ne s’agit pas exactement d’un CMS, mais plutôt d’un système de gestion de pages statiques.
+Il faut programmer sois-même les pages web, le code pour engendrer les menus…
+J’ai programmé des filtres pour rendre ce site multilangue par exemple
+Vous pourrez trouver beaucoup d’informations sur le site officiel de nanoc.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Comme Andy Lester me l’a fait remarqué. ack est un simple fichier perl qu’il suffit de copier dans son répertoire personnel ~/bin. Maintenant j’ai ack sur mon serveur professionnel.
Il suffit d’aller sur http://betterthangrep.com pour le télécharger.
+Sincèrement, je ne comprend pas qu’ack ne soit pas une commande implémentée par défaut sur les systèmes UNIX. Je ne peux vraiment plus m’en passer, il m’est devenu aussi essentiel qu’un which ou un find.
Un des mes usages principaux de grep est
La plupart du temps c’est suffisant, mais ajouter de la coloration améliore beaucoup l’utilité de cette commande. Il existe déjà un outil pour ça : il s’appelle ack-grep sous Ubuntu. Comme je ne peux pas l’installer sur le serveur de mon entreprise, j’en ai créé un moi-même en quelques lignes :
#!/usr/bin/env zsh
+(($#<1)) && { print 'usage: ack "regexp"' >&2; exit 1 }
+
+listeFic=( **/*(.) )
+autoload zargs
+zargs -- $listeFic -- grep $1 | perl -ne 'use Term::ANSIColor;
+if (m/([^:]*)(:.*)('$1')(.*)/) {
+ print color("green").$1;
+ print color("reset").$2;
+ print color("black","on_yellow").$3;
+ print color("reset").$4."\n";
+} 'Pour mon utilisation personnelle et celle de mon équipe c’est suffisant. J’espère que ça pourra vous aider.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+Lost Highway ne laisse pas indiférent. Le revoir ne lasse pas même s’il parrait complètement obscur. C’est une des forces de David Lynch. Il faut garder à l’esprit qu’il n’existe pas une seule interprétation possible et cohérente du film. Seul David Lynch pourrait donner une explication complète du film. Je donne cependant quelques clés que j’ai découverte qui aident à suivre le film sans être complètement perdu. Ces clés devraient vous aider à vous faire votre propre idée du film…
+La première fois que j’ai vu Lost Highway je me suis senti un peu perdu. J’en ai alors cherché le sens. Voilà ce que j’ai pu trouver sur Internet :
+sans compter les multiples avis trouvés sur les forums. Tout cela ne me paraissait pas convaincant. J’ai alors réussi à trouver deux articles (en anglais) qui proposent de bien meilleures interprétations. Mais aucun des deux ne m’a complètement convaincu :
+Il faut garder à l’esprit qu’il n’existe pas une seule interprétation possible et cohérente du film. Seul David Lynch pourrait donner l’explication complète du film.
+Je donne quelques clés aidant à suivre le film sans être complètement perdu. Ces clés devraient vous aider à vous faire votre propre idée du film.
+
+À l’instar du protagoniste chacun voit dans ce film ce qu’il a envie d’y voir. Nous pouvons nous y perdre simplement parce que nous pouvons nous perdre dans notre propre esprit. C’est une invitation à la réflexion. Regarder ce film c’est un peu comme passer un test de Rorschach. Qu’y voit-on ? Chacun y met un peu de sa propre personnalité dans l’explication du film.
+En général en essayant d’expliquer ce film, on se perd un peu dans notre pensée. Et souvent on échoue à tout expliquer. Il y a toujours un point qui rend la construction incohérente avec le film. C’est pourquoi rechercher une explication unique est un entreprise vaine.
+Je donne une interprétation et non pas une explication. Ma vision des choses, me semble cohérente. Cependant il est très probable que mon adhésion au film soit très différente de la votre. Il y a certainement beaucoup d’autres explications qui restent cohérentes.
+J’écris cet article, parce que j’ai l’impression d’en avoir trouver une qui marche pour plus de 97% du film (peut-être 100%, mais j’en doute, il faudrait que je le revois encore une fois).
+Tout se passe dans la mémoire de Fred
+Tout d’abord, il est clair que comprendre le film comme simplement un film fantastique ne fonctionne pas. En suivant ce point d’entrée on en fini pas de se heurter à des détails incompréhensibles.
+Mon hypothèse de départ c’est que le film dépeint la représentation de la réalité que s’en fait Fred. Chaque fois qu’il essaye d’échapper à la réalité, celle-ci finira par le rattraper.
+Fred a commis un acte horrible, un meurtre, et essaye de réparer sa mémoire pour accepter son acte. Il va alors s’inventer des réalitées alternatives.
+Cette interprétation me semble valide à cause du dialogue au début du film avec les policiers qui demandent au protagoniste s’il a une caméra :
+++“Do you own a video camera?”
+
+“No, Fred hates them.”
+“I like to remember things my own way.”
+“What do you mean by that?”
+“How I remember them, not necessarily the way they happened.”
Ce que l’on peut traduire approximativement par :
+++– Avez-vous une caméra ?
+
+– Non, Fred les détestes.
+– J’aime me rappeler les choses à ma façon.
+– Qu’entendez-vous par là ?
+– Je me rappelle des choses pas nécessairement comme elles se sont passées.
Ainsi, ce que l’on voit n’est pas la réalité, mais la réalité telle que le conçoit Fred. Il est donc le Dieu de cette réalité. Ainsi les interprétations mystiques faisant intervenir le Diable ont une certaine validité.
+
+Qui est donc ce personnage étrange et inquiétant ? Un être capable d’ubiquité qui dit être invité par Fred dans sa maison ? Sans sourcils, le visage blême, les yeux écarquillés fixant sans relâche les faits et gestes de Fred.
+C’est certainement une des clés du film. À mon avis, il représente la partie mauvaise de Fred. Certainement la jalousie. Si j’étais Catholique je dirai Satan, le tentateur. Il n’agit jamais, mais ne fait qu’observer et filmer. Par contre c’est lui qui donne les armes à Fred pour tuer Dick Laurent. Fred l’a laissé entrer chez lui et il ne peut plus s’en débarrasser. Un peu comme le Iago de Shakespeare est enfermé dans sa jalousie. Le personnage mystérieux prend toute l’importance, il le ronge de l’intérieur. Il aide Fred à accomplir les actes de violences et aussi l’oblige à se souvenir de la réalité.
+Quand il fait l’amour à Renée il voit le visage de l’homme mystérieux à la place du visage de sa femme. En réalité, il s’agit de la même personne d’après Fred. Ce serait donc elle qui est la source de son mal intérieur.
+C’est certainement l’homme mystérieux (ou Fred lui-même) qui est à l’origine de ces cassettes. Le rôle des cassettes est double :
+Ici, tout n’est pas donné, on garde une assez grande liberté. Mais on a des indices.
+Je dirais que le protagoniste est un garagiste qui est tombé amoureux d’une actrice porno. Il l’a certainement vu la première fois accompagnant le fameux Dick Laurent. Voyant qu’il ne peut pas l’avoir pour lui, fou de jalousie il tue Dick Laurent dans un motel où celui-ci à couché avec Renée.
+On a la liberté de décider s’il a vraiment tué la femme ou pas. Dans ma première vision du film, j’avais envie de dire qu’il ne la tue pas. Mais qu’une fois le meurtre commis, il va chez elle, sonne pour lui annoncer la mort de Dick Laurent. Il a alors juste le temps de s’enfuir, la police à ses trousses.
+La première partie resemble à la réalité. Il a vraiment tué sa femme. Il se fait arrété et condamné (certainement à mort). Par contre on ne sait pas s’il est aussi allé tuer Andy.
+La seconde hypothèse me semble plus vraisemblable, car il y a plus de recoupements possibles. La première me semble aussi cohérente. C’est cette première hypothèse que j’avais émise lors de mon premier visionnage du film.
+Ce qui montre la force de ce film c’est de se dire qu’il y a de nombreuses autres hypothèses qui pourraient aussi bien fonctionner. C’est le fameux effet Rashomon. Plusieurs personnes peuvent décrire de façon cohérentes ce qu’elles ont vu, mais toutes les descriptions sont incohérentes entres-elles.
+Il y aurait encore beaucoup à dire sur l’analyse de ce film. Mais il me semble que j’ai rassemblé l’essentiel des clés pour sa compréhension.
+Il me semble qu’avoir à l’esprit l’effet “test de Rorschach” est essentiel lors de la visualisation de ce film.
+J’aimerai avoir votre opinion ; mon interprétation tient-elle la route ?
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Ma femme a acheté pour environ 500€ (au moins) de séries télé sur iTunes. Mais elles s’est trompé pour la première saison de Battlestar Galactica. Qu’elle a téléchargé en anglais. Hors comme les séries sont protégées, on ne peut simplement pas voir la série avec des sous-titres !
++WTF? +
+Résultat des courses, ma femme n’achetera plus de séries sur iTunes tant qu’elles resteront protégées par DRM, qu’elle ne pourront pas être gravées sur DVD (pour être regardées sur la télé). Et comme elle est bien moins prompte à acheter des DVD que simplement cliquer sur un bouton.
+Ca fera nettement moins d’argent pour vous les ayant-droits !!!
+Et ma femme ne pourra pas voir ces épisodes.
C’est ce qu’on appelle une cooperation ‘LOSE-LOSE’.
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Edit: Maintenant j’utilise git push -u
J’utilise Git pour synchroniser des projets personnels. C’est pourquoi quand je crée une branche locale je souhaite quasiment toujours qu’elle soit aussi créée en externe (remote).
+Voici le script que j’utilise pour accomplir cette tâche :
+#!/usr/bin/env zsh
+
+if (($#<1)); then
+ print -- "usage: $0:t branch_name" >&2
+ exit 1
+fi
+
+branch=$1
+git br ${branch}
+git co ${branch}
+git config branch.${branch}.remote origin
+git config branch.${branch}.merge refs/heads/${branch}Bien sûr, je suppose qu’origin est déjà configurée.
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+Màj : Actuellement j’utilise github avec des repository privés. Je paye une somme très raisonnable pour ce service. Si vous voulez être complètement autonome, je vous conseille d’utiliser gitolite sur votre propre serveur accessible sur le web.
+J’utilise Git pour gérer mes projets personnels. J’ai un repository centralisé et tous mes ordinateurs se synchronisent avec lui. Cependant, dans la documentation officielle, je n’ai pas trouvé clairement ce que je souhaitais.
+En d’autres termes, si vous souhaitez utiliser le type de workflow que SVN proposait avec Git (et ses avantages), voici comment procéder.
+Disons que j’ai déjà un projet et que je veuille en créer un nouveau.
+ +Maintenant tous les fichiers du répertoire to/project/directory/ sont versionnés. Si vous voulez ignorer certains fichiers il suffit de modifier le fichier .gitignore.
Ensuite, il faut placer ce projet dans un répertoire accessible via Internet.
+ +Màj: La meilleure solution est d’installer gitolite pour installer un serveur git sur sa machine. Gitolite permet de gérer la gestion des droits d’utilisateurs, ceux-ci n’ayant pas accès à un shell sur la machine.
+Maintenant à partir de n’importe quel ordinateur, voici ce que vous pouvez faire :
+ +et local_directory contiendra un projet à jour.
+
Je vous conseille de faire la même opération sur l’ordinateur qui à servi à créer le projet de façon à vérifier que tout fonctionne correctement.
+Pour résumer vous avez maintenant un repository sur Internet et un ou plusieurs ordinateurs lui sont associés. Maintenant il faut que tout soit toujours synchronisé.
+Avant de commencer à travailler, la première chose à faire est de récupérer les modification à partir d’Internet vers votre poste local :
+Ensuit vous pouvez travailler en faisant (plusieurs fois) :
+ +Quang vous voulez envoyez les modifications locales sur Internet, il suffit de faire :
+Tout devrait être bon.
+Si vous avez des problèmes avec le push et le pull ; vérifiez votre fichier .git/config. Il devrait contenir les lignes suivantes :
Bien, maintenant que tout semble bon, il faut encore s’occuper de quelques petites choses (sinon, SVN suffirait). Git est complètement orienté sur la décentralisation et la création de nouvelles branches sur le même poste. Synchroniser des branches sur plusieurs serveurs différent n’est pas une opération naturelle.
+C’est pourquoi j’ai créé deux simples scripts pour automatiser cette opération. Un script pour créer un branche localement et en ligne. Un autre script pour récupérer les branches en lignes qui ne sont pas présente localement.
+Ainsi, lorsque je veux créer une nouvelle branche (localement et ligne) ; je lance le script :
+git-create-new-branch branch_name
+et quand je suis sur un autre ordinateur et que je veux récupérer les branches crées sur un autre poste, j’exécute :
+git-get-remote-branches
+Voici le code des deux script (en zsh) :
+#!/usr/bin/env zsh
+
+# recup branches not on local
+localbranches=( $(git br | sed 's/\*/ /') )
+remoteMissingBranches=( $(git br -r | \
+ egrep -v "origin/HEAD|(${(j:|:)localbranches})" ) )
+for br in $remoteMissingBranches; do
+ branch=${br#origin/}
+ print "get remote branch $branch"
+ git br ${branch}
+ git config branch.${branch}.remote origin
+ git config branch.${branch}.merge refs/heads/${branch}
+done
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Mon économiseur d’écran ne fonctionnait plus sous Mac OS X 10.6 Snow Leopard(c). Après un peu de recherche sous google, le problème semblait pouvoir être réglé avec une recompilation. Cependant, même en recomilant en 64 bits ça ne fonctionnait toujours pas. Après un peu plus de recherches (merci à ElectricSheep ), j’ai découvert les bons paramètres.
+
+Pour l’instant je ne l’ai pas compilé pour être compatible Tiger et Leopard. Je ne connais pas assez bien XCode pour savoir comment désactiver le garbage collector sur la version 32 bits et l’activer sur la version 64 bits.
+Il a été assez difficile de découvrir toutes ces informations. J’espère que cet article aura pu aider quelqu’un.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Que ce soit pour surfer en toute sécurité depuis un accès
Ensuite de mon portable ou de mon ordinateur local, je dois simplement lancé la merveilleuse commande :
+ +et un proxy localhost écoutant le port 9050.
J’ai eu cette information à partir de cet article.
+J’ai un Mac avec Snow Leopard(c) à la maison. Il ne suffit pas de modifier le fichier /etc/sshd.config pour changer le port d’écoute d’sshd. Le système utilise launchd pour lancer les démons.
J’ai posé cette question sur Apple Discussions dans ce fil de discussion. Merci à tous ceux qui m’ont aidé. Et la solution est :
+Créer un fichier /Library/LaunchDaemons/ssh-443.plist contenant :
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+ <key>Disabled</key>
+ <false/>
+ <key>Label</key>
+ <string>local.sshd</string>
+ <key>Program</key>
+ <string>/usr/libexec/sshd-keygen-wrapper</string>
+ <key>ProgramArguments</key>
+ <array>
+ <string>/usr/sbin/sshd</string>
+ <string>-i</string>
+ </array>
+ <key>Sockets</key>
+ <dict>
+ <key>Listeners</key>
+ <dict>
+ <key>SockServiceName</key>
+ <string>https</string>
+ </dict>
+ </dict>
+ <key>inetdCompatibility</key>
+ <dict>
+ <key>Wait</key>
+ <false/>
+ </dict>
+ <key>StandardErrorPath</key>
+ <string>/dev/null</string>
+ <key>SHAuthorizationRight</key>
+ <string>system.preferences</string>
+</dict>
+</plist>C’est une copie de /System/Library/LaunchDaemons/ssh.plist avec quelques modifications :
SockServiceName est devenu https au lieu de sshLabel est passé de com.openssh.sshd à quelque chose qui n’existait pas comme local.sshdEncore une fois j’espère que ça a pu être utile.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ J’ai arrété d’utiliser whos.amung.us en faveur de Google Analytics.
+La plupart du temps je préfère ne pas utiliser le même produit que tout le monde. J’aime bien essayer des choses un peu nouvelles. Mais whosamung.us avait trop de publicités. Je devais affichier une de leur image sur mon site qui n’écrivait que le nombre de personne actuellement présentes. Pas les nombres de visites.
+C’est pourquoi j’utilise maintenant google analytics. Le problème reste entier pour les navigateurs sans javascript.
+Donc pour l’instant
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ iDisk va bientôt disparaître. Cet article est donc presque complètement obsolète.
+J’ai mis à jour mon script avec une version incrémentale bien plus pratique. En plus depuis l’écriture de cet article Apple(c) semble avoir nettement amélioré la vitesse de ses serveurs en Europe.
+En France l’iDisk d’Apple(c) est très lent. La vitesse d’upload me rapelle l’époque des modem 56k, c’est dire. La plupart du temps les opérations telles que lister le contenu d’un répertoire prennent au moins 30 secondes (pour 15 éléments). Renommer un répertoire échoue presque systématiquement.
+Apple(c) utilise des serveurs WebDav pour héberger les fichiers. Le protocole fonctionne sur le port 80 (comme http). Je me suis rendu compte qu’utiliser WebDav via https fontionne bien mieux (2 à 3 fois plus rapide avec moins d’erreurs). Mais, ça reste quand même très lent et insuffisant.
+J’uploade mes fichiers à partir de mon Mac et de temps en temps à partir d’un PC sous Ubuntu (iDisk monté avec webdavfs).
+Voici le script que j’utilise pour synchroniser mon site web (non créé avec iWeb(c)) avec le maximum de sécurité. Chaque opération est répétée jusqu’à ce qu’elle fonctionne.
+Les idées sont :
+Jusqu’ici j’utilise rsync qui n’est en fait pas plus efficace qu’une simple copie cp avec WebDav. Je devrais utiliser une méthode pour mémoriser les changements entre chaque publication.
En réalité quand je suis sur mon Mac j’utilise Transmit qui est vraiment très bien et surtout beaucoup plus efficace que le finder pour synchroniser des fichiers. Ensuite, je ne fait que le “swap” des répertoires.
+Mon script prend un paramètre -s pour ne faire que le “swap”. Il prend aussi une option -a pour envoyer le fichier index.html qui va rediriger vers ma nouvelle page principale (iWeb(c) à la fâcheuse habitude de le remplacer).
Pour utiliser le script vous devriez remplacer la valeur de la variable mobileMeUser par votre nom d’utilisateur mobileMe(c).
#!/usr/bin/env zsh
+
+# Script synchronisant le site sur me.com
+# normalement, le site est indisponible le moins de temps possible
+# le temps de deux renommages de répertoire
+
+mobileMeUser="yann.esposito"
+siteName="siteName"
+
+# Depending of my hostname the
+if [[ $(hostname) == 'ubuntu' ]]; then
+ iDisk='/mnt/iDisk'
+else
+ iDisk="/Volumes/$mobileMeUser"
+fi
+
+root=$HOME/Sites/$siteName
+destRep=$iDisk/Web/Sites/$siteName
+
+[[ ! -d $root ]] && {
+ print -- "$root n'existe pas ; vérifiez la conf" >&2;
+ exit 1
+}
+
+[[ ! -d $destRep ]] && {
+ print -- "$destRep n'existe pas, veuillez remonter le FS" >&2;
+ exit 1
+}
+
+if [[ $1 == '-h' ]]; then
+ print -- "usage: $0:h [-h|-a|-s]"
+ print -- " -a sychronise aussi l'index"
+ print -- " -h affiche l'aide"
+ print -- " -s swappe simplement les répertoires"
+fi
+
+if [[ $1 == '-a' ]]; then
+ print -- "Synchronisation de l'index (${destRep:h})"
+ rsync -av $root/index.html ${destRep:h}/index.html
+fi
+
+print -- "Root = $root"
+print -- "Dest = $destRep"
+
+if [[ ! $1 = '-s' ]]; then
+ [[ ! -d $destRep.tmp ]] && mkdir $destRep.tmp
+ print -P -- "%B[Sync => tmp]%b"
+ result=1
+ essai=1
+ while (( $result > 0 )); do
+ rsync -arv $root/Scratch/ $destRep.tmp
+ result=$?
+ if (( $result > 0 )); then
+ print -P -- "%BEchec du rsync%b (essai n°$essai)" >&2
+ fi
+ ((essai++))
+ done
+fi
+
+# SWAP
+print -P -- "%B[Swap des Répertoires (tmp <=> target)]%b"
+essai=1
+while [[ -e $destRep.old ]]; do
+ print -n -- "suppression de $destRep.old"
+ if ((essai>1)); then
+ print " (essai n°$essai)"
+ else
+ print
+ fi
+ ((essai++))
+ \rm -rf $destRep.old
+done
+
+print -- " renommage du repertoire sandard vers le .old"
+essai=1
+while [[ -e $destRep ]]; do
+ mv $destRep $destRep.old
+ (($?)) && print -- "Echec du renommage (essai n°$essai)" >&2
+ ((essai++))
+done
+
+print -- " renommage du repertoire tmp (nouveau) vers le standard"
+print -P -- " %BSite Indisponible%b $(date)"
+essai=1
+while [[ ! -e $destRep ]]; do
+ mv $destRep.tmp $destRep
+ (($?)) && print -P -- "%B[Site Indisponible]%b(essai n°$essai) Echec du renommage (mv $destRep.tmp $destRep)" >&2
+ ((essai++))
+done
+
+print -P -- "\t===\t%BSITE DISPONIBLE%b\t==="
+
+print -- " renommage du repertoire old vers le tmp"
+essai=1
+while [[ ! -e $destRep ]]; do
+ mv $destRep.old $destRep.tmp
+ (($?)) && print -P -- "Echec du renommage n°$essai" >&2
+ ((essai++))
+done
+
+print -P -- " publication terminée"#!/usr/bin/env zsh
+
+# Author: Yann Esposito
+# Mail: yann.esposito@gmail.com
+# Synchronize with "mobileMe" iDisk account.
+
+mobileMeUser="firstname.lastname"
+siteName="siteName"
+
+# Depending of my hostname the
+if [[ $(hostname) == 'ubuntu' ]]; then
+ iDisk='/mnt/iDisk'
+else
+ iDisk="/Volumes/$mobileMeUser"
+fi
+
+root=$HOME/Sites/$siteName
+destRep=$iDisk/Web/Sites/$siteName
+
+[[ ! -d $root ]] && {
+ print -- "$root does not exist ; please verify the configuration ($0)" >&2;
+ exit 1
+}
+
+[[ ! -d $destRep ]] && {
+ print -- "$destRep does not exist, please mount the filesystem" >&2;
+ exit 1
+}
+
+if [[ $1 == '-h' ]]; then
+ print -- "usage: $0:h [-h|-a|-s]"
+ print -- " -a sychronize primary index"
+ print -- " -h show this help"
+ print -- " -s only swap directories"
+fi
+
+if [[ $1 == '-a' ]]; then
+ print -- "Index synchronisation (${destRep:h})"
+ rsync -av $root/index.html ${destRep:h}/index.html
+fi
+
+print -- "Root = $root"
+print -- "Dest = $destRep"
+
+if [[ ! $1 = '-s' ]]; then
+ [[ ! -d $destRep.tmp ]] && mkdir $destRep.tmp
+ print -P -- "%B[Sync => tmp]%b"
+ result=1
+ essai=1
+ while (( $result > 0 )); do
+ rsync -arv $root/Scratch/ $destRep.tmp
+ result=$?
+ if (( $result > 0 )); then
+ print -P -- "%Brsync failed%b (try n°$essai)" >&2
+ fi
+ ((essai++))
+ done
+fi
+
+# SWAP
+print -P -- "%B[Directory Swap (tmp <=> target)]%b"
+essai=1
+while [[ -e $destRep.old ]]; do
+ print -n -- "remove $destRep.old"
+ if ((essai>1)); then
+ print " (try n°$essai)"
+ else
+ print
+ fi
+ ((essai++))
+ \rm -rf $destRep.old
+done
+
+print -- " renommage du repertoire sandard vers le .old"
+essai=1
+while [[ -e $destRep ]]; do
+ mv $destRep $destRep.old
+ (($?)) && print -- "Failed to rename (try n°$essai)" >&2
+ ((essai++))
+done
+
+print -- " renaming folder tmp (new) to the standard one"
+print -P -- " %BThe WebSite isn't working%b $(date)"
+essai=1
+while [[ ! -e $destRep ]]; do
+ mv $destRep.tmp $destRep
+ (($?)) && print -P -- "%B[WebSite not working]%b(try n°$essai) Failed to rename (mv $destRep.tmp $destRep)" >&2
+ ((essai++))
+done
+
+print -P -- "\t===\t%BWEBSITE SHOULD WORK NOW%b\t==="
+
+print -- " rename old folder to tmp folder"
+essai=1
+while [[ ! -e $destRep ]]; do
+ mv $destRep.old $destRep.tmp
+ (($?)) && print -P -- "Failed to rename n°$essai" >&2
+ ((essai++))
+done
+
+print -P -- " Publish terminated"
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ In fact this method works for old threads. But it fails to create new post threads. This is why I tried and be conquered by intensedebate, as you can see in the bottom of this page.
+Remark I didn’t have any comment on my blog when I switched. Therefore my lack of influence was a good thing :-).
+Before begining, I must state that I love Disqus.
+I know there is a similar blog entry at Trephine.org. Here I just add a straight and easy way to load disqus asynchronously using jQuery.
+I also know there is a jQuery plugin to make just that. Unfortunately I had some issue with CSS.
+Now let’s begin.
+Why should I want to load the disqus javascript asynchronously?
+I give a solution with jQuery, but I’m certain it will work with many other js library.
+replace:
+ +by
+If you forget the window.disqus_no_style=true; then your page will be blank. Simply because without this option, the javascript use a document.write action after the document was closed, which cause a complete erasing of it.
But with this option you still need to provide a CSS. This is why you have to copy the css code from the embed.js file and rewrite it in a CSS file. You can download the CSS I obtained.
Now it’s done. I believe all should be fine but I just finished the manip for my own site only 1 hour ago. Therefore there should be some error, tell me if it is the case.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ J’ai écrit un article sur la façon dont j’ai essayé d’intégrer Disqus. Mon problème majeur avec Disqus c’était que ma page ne s’affichait pas correctement tant que les commentaire n’avait pas fini de s’afficher. Ça m’est arrivé plusieurs fois d’avoir ma page complètement bloquée parce que les serveurs de Disqus ne répondait pas. C’est pourquoi j’ai essayer de l’inclure de manière asynchrone. Cependant j’ai eu des difficultés pour le faire fonctionner correctement.
+De plus il n’a pas été trivial de faire en sorte que les commentaires soient commun à plusieurs pages différentes (chaque page à trois représentations différentes, une par language plus une version multi-langue).
+Je dois reconnaître que je suis un peu triste de quitter Disqus parce que pour chacun de mes problèmes giannii m’a aidé du mieux qu’il a pu. Cependant les problèmes que j’ai eu étaient inhérents à des choix de conceptions plus que de simples petits problèmes techniques.
+Lorsque j’ai commencé à intégrer Disqus je n’ai jamais essayé Intense Debate. Maintenant que j’ai essayé je doit dire que je suis conquis. Il correspond exactement à ce que j’espérais de ce type de service.
+Pour le rendre complètement asynchrone il suffit de récupérer leur js commun et de remplacer la ligne suivante :
+ +par (si vous utilisez jQuery) :
+Pour conclure les avantages majeurs (pour moi) d’Intense Debate par rapport à Disqus:
+Voilà.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Here is how I done the tag cloud of my blog. It is done mostly in jQuery. All my site is static and pages are generated with nanoc. It is (in my humble opinion) the modern geek way to make a website.
+This is why I’ll give only a Ruby Generator, not a full javascript generator. But you can easily translate from Ruby to Javascript.
+Here is what you should obtain:
+<%= tagCloud %>
+Here is the simple jQuery code:
+This code will hide all the div containing links to articles containing the tag. And create a function do show the div containing the tag.
+For each tag I create a span element:
+and a div containing links associtated to this tag:
+Here is how I generate this using nanoc 2.
+If you want to make it fully jQuery one, it shouldn’t be too difficult, to use my ruby code and translate it into javascript.
+In a first time tags correpond of the list of all tags.
A function to create a data structure associating to each tag its occurence.
+I also need a data structure who associate to each tag a list of pages (at least url and title).
+Calculate the real size of each tag to be displayed.
+I choosen not to use the full range of size for all the tag. Because if no tag has more than n (here 10) occurences, then it doesn’t deserve to be of the maximal size.
def tagRealSize
+ tags=tagNumber
+ max=tags.values.max
+ min=tags.values.min
+ # size in CSS em.
+ minSize=1.0
+ maxSize=2.5
+ tagSize={}
+ tags.each do |t,n|
+ if ( max == min )
+ tagSize[t]=minSize
+ else
+ # normalized value between 0 and 1
+ # if not tag appear more than 10 times,
+ # then it cannot have the maximal size
+ tagSize[t]=[ ( n - min + 0.0 ) / ( max - min ) ,
+ (n - min) / 10.0 ].min
+ # from normalized size to real size
+ tagSize[t]=( tagSize[t] ) * (maxSize - minSize) + minSize
+ end
+ end
+ return tagSize
+endFinaly a function to generate the XHTML/jQuery code
+# generate an XHTML/jQuery code for tag cloud
+def tagCloud
+ tagLinks=tagRefs
+ tagSize=tagRealSize
+
+ # begin to write the code
+ tagCloud=%{<script type="text/javascript">
+ $(document).ready( function(){$('.list').hide();} );
+ function tagSelected(id) {
+ $('.list').hide();
+ $('#'+id).fadeIn();
+ $('.tag.selected').removeClass('selected');
+ $('#tag_'+id).addClass('selected');
+ }
+ </script><div id="tagcloud">}
+ # Creation of the tags <span>
+ tagSize.sort{|a,b| a[0].downcase <=> b[0].downcase}.each do |t,s|
+ tag_in_id=t.gsub(/\W/,'_')
+ # HTML protected version of the tag
+ # for example, replace ' ' by ' '
+ protected=t.gsub(/&/,'&').gsub(/ /,' ').gsub(/</,'<').gsub(/>/,'>')
+ tagCloud <<= %{
+ <span style="font-size: #{s}em;"
+ class="tag"
+ onClick="tagSelected('#{tag_in_id}')"
+ id="tag_#{tag_in_id}">
+ #{protected}
+ </span> }
+ end
+ tagCloud <<= %{</div><div id="hiddenDivs" >}
+ # Creation of the divs containing links associated to a tag.
+ tagLinks.each do |t,l|
+ tag_in_id=t.gsub(/\W/,'_')
+ tagCloud <<= %{
+ <div id="#{tag_in_id}" class="list">
+ <h4>#{t}</h4><ul>}
+ # generate the link list
+ l.each do |p|
+ tagCloud <<= %{<li><a href="#{p.path}">#{p.title}</a></li>}
+ end
+ tagCloud <<= %{</ul></div>}
+ end
+ tagCloud <<= %{</div>}
+ return tagCloud # yeah I know it is not necessary
+endYou can download the complete file to put in your ‘lib’ directory. Beware, it is a nanoc 2 version, you’ll have to make some small changes like replace @pages by @items to be nanoc3 compatible.
Of course to be nice you need the associated CSS
+That’s all folks.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ My problem is simple:
+I want to filter a text except some part of it. I can match easily the part I don’t want to be filtered. For example
+ +I searched a better way to do that, but the best I can do is using split and scan.
def allExceptCode( f, content )
+ # Beware the behaviour will change if you add
+ # parenthesis (groups) to the regexp!
+ regexp=/<code[^>]*>.*?<\/code>|<pre[^>]*>.*?<\/pre>/m
+ tmp=""
+ mem=[]
+ content.scan(regexp).each do |c|
+ mem <<= c
+ end
+ i=0
+ content.split(regexp).each do |x|
+ tmp <<= send(f,x)
+ if not mem[i].nil?
+ tmp <<= mem[i]
+ i+=1
+ end
+ end
+ tmp
+endAn usage is:
+ +A better syntax would be:
+I would expect the split make a search on a regular expression and then give the matched expression into the $& variable. But it is not the case.
If someone know a nicer way to do that I will be happy to know how.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ J’ai déjà discuté de la façon dont je synchronise mon site web sur mobileme. J’ai amélioré mon script pour le rendre incrémental.
+Voici mon script, il créé tout d’abord un fichier qui contient la liste des fichiers avec leur hash. Afin de les comparer avec ceux qui sont en ligne sans avoir à les parcourir. Ensuite pour chaque fichier qui semble différent, je met à jour le contenu.
+Cependant même avec ce script j’ai encore des problèmes. Dû à webdav. En particulier le renommage de répertoire. Par exemple :
+ mv folder folder2
+Retourne OK et pourtant :
+ $ ls folder folder2
+Bouuhh…
+Pour résoudre ce type de problèmes j’utilise un framework en zsh. Il résout presque tous les problèmes liés à webdav à l’exception du renommage de répertoire.
+ #!/usr/bin/env zsh
function samelineprint { print -n -P – "\r$*" }
+maxessais=300
+function trymkdir { target=“$1” print – mkdir -p $target local essai=1 while ! mkdir -p $target; do samelineprint "Echec: essai n°$essai" ((essai++)) ((essai>maxessais)) && exit 5 done print }
+function trycp { element=“$1” target=“$2” if [[ ! -d ${target:h} ]]; then trymkdir ${target:h} fi local essai=1 print – cp $element $target while ! $element $target; do samelineprint "Echec: essai n°$essai" ((essai++)) ((essai>maxessais)) && exit 5 done print }
+function tryrm { target=“$1” local essai=1 local options=’’ [[ -d $target ]] && options=‘-rf’ print – rm $options $target while ! rm $options $target; do samelineprint "Echec: essai n°$essai" ((essai++)) ((essai>maxessais)) && exit 5 done essai=1 while [[ -e $element ]]; do samelineprint “rm reussi mais fichier source non disparu n°$essai” sleep 1 ((essai++)) ((essai>maxessais)) && exit 5 done print }
+function tryrename { element=“$1” target=“$2” local essai=1 while [[ -e $target ]]; do samelineprint “Echec n°$essai le fichier $target existe déjà” ((essai++)) ((essai>maxessais)) && exit 5 sleep 1 done print – mv $element $target while ! mv $element $target; do samelineprint "Echec: essai n°$essai" ((essai++)) ((essai>maxessais)) && exit 4 done essai=1 while [[ -e $element ]]; do samelineprint “mv reussi mais fichier source non disparu n°$essai” sleep 1 ((essai++)) ((essai>maxessais)) && exit 5 done print }
+Et voici le code qui me permet de synchroniser mon site web. Il y a une partie un peu incompréhensible. C’est pour enlever les mail réencodés par le filtre bluecloth qui est une implémentation de markdown. Mes mails, sont encodés à chaque fois de façon différente à chaque réengendrement de page html. C’est pourquoi je les enlève pour ne pas les uploadés inutilement à chaque fois.
+ #!/usr/bin/env zsh
source $0:h/config
+source $0:h/webdav-framework
+if [[ $1 == ‘-h’ ]]; then print – “usage : $0:h [-h|-s|-d]” print – " -a sychronise aussi l’index" print – " -h affiche l’aide" print – " -d modification directe (pas de swap)" print – " -s swappe simplement les répertoires" fi
+function incrementalPublish { local ydestRep=destRepsuffix localRef=“$srcRep/map.yrf” print – “Creation du fichier de references” create-reference-file.sh > $localRef remoteRef="/tmp/remoteSiteMapRef.$$.yrf" if [[ ! -e "$ydestRep/map.yrf" ]]; then # pas de fichier de reference sur la cible print – “pas de fichier de reference sur la cible, passage en mode rsync” rsyncPublish swap else trycp “$ydestRep/map.yrf" "$remoteRef” typeset -U filesToUpdate filesToUpdate=( $(diff $localRef $remoteRef | awk ’/1/ {print $2}' ) ) if ((${#filesToUpdate} == 1)); then print – “Seul le fichier ${filesToUpdate} sera téléversé" elif ((${#filesToUpdate}<10)); then print –”${#filesToUpdate} fichiers seront téléversés :" print -- "${filesToUpdate}" else print – “${#filesToUpdate} fichiers seront téléversés” fi # copy all file with some differences # except the map in case of error for element in $filesToUpdate; do if [[ $element == “/map.yrf” ]]; then continue fi if [[ -e srcRepelement ]]; then trycp srcRepelement ydestRepelement else tryrm ydestRepelement fi done # if all went fine, copy the map file trycp $srcRep/map.yrf $ydestRep/map.yrf # remove the temporary file }
+function rsyncPublish { result=1 essai=1 while (( $result > 0 )); do print – rsync -arv $srcRep/ $destRep.tmp if ((!testmode)); then rsync -arv $srcRep/ destRep.tmpfiresult=? if (( $result > 0 )); then print -P -- "%BEchec du rsync%b (essai n°$essai)" >&2 fi ((essai++)) done }
+function swap { print -P – “%B[Directory Swap (tmp <=> target)]%b” [[ -e $destRep.old ]] && tryrm $destRep.old
+print -- " renommage du repertoire sandard vers le .old"
+tryrename $destRep $destRep.old
+
+print -- " renommage du repertoire tmp (nouveau) vers le standard"
+print -P -- "%B[Site Indisponible]%b $(date)"
+tryrename $destRep.tmp $destRep
+print -P -- "%B[Site Disponible]%b $(date)"
+
+print -- " renommage du repertoire old vers le tmp"
+tryrename $destRep.old $destRep.tmp
+
+print -P -- " publication terminée"}
+print – “Root = $webroot” print – “Dest = $destRep”
+if [[ “$1” = “-s” ]]; then swap else print -P “Copie de l’init” -f $webroot/Scratch/multi/index.html $webroot/index.html
+if [[ "$1" = "-d" ]]; then
+ suffix=""
+else
+ suffix=".tmp"
+fi
+print -P -- "%BSync%b[${Root:t} => ${destRep:t}$suffix]"
+incrementalPublishC’est ma façon de remplacer rsync avec des filesystem qui ne permettent pas de l’utiliser. J’espère que ça pourra vous être utile. Je serai heureux de savoir si quelqu’un à une idée sur comment gérer le problème de renommage de répertoire avec webdav.
<>↩
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Pour les développeur de site web Internet Explorer est un cauchemar. C’est pourquoi j’utilise un style complètement différent pour ce navigateur. Avec la librairie jQuery.
+ $(document).ready( function() { if ($.browser[“msie”]) { // include the ie.js file $(‘head’).append(’
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+
tlpl: Une introduction rapide à Parsec. Un parser en Haskell.
++From String: +
+(1+3)*(1+5+9)+To data structure: +
+
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+tlpl: Une méthode de gestion des mots de passes que j’utilise avec succès depuis quelques années.
+sha1( mot_de_passe + nom_de_domaine )
+Je ne mémorise qu’un seul mot de passe de très bonne qualité. J’utilise des mots de passe différents sur tous les sites.
Avant de commencer, je tiens à préciser qu’il s’agit d’une tentative de vous vendre mon appli iPhone ;-).
+Vous êtes toujours là ? Bon, d’accord, même si vous ne téléchargez pas mon application vous pouvez quand même utiliser ma méthode. Elle est à la fois très sûre et simple à utiliser.
+Si vous souhaitez simplement utiliser le système sans essayer de comprendre comment ça marche derrière vous pouvez aller à la fin de cet article en cliquant ici.
+++Même les paranoïaques peuvent avoir des ennemis.
+
Imaginez que vous trouviez un très bon mot de passe. Vous l’utilisez sur gmail, amazon, PayPal, twitter, facebook… Plus tard, vous découvrez un super petit jeu en ligne très sympa. Vous devez vous enregistrer pour y jouer. Le site vous demande votre email et un mot de passe. Quelques semaines/mois se passent. La machine qui héberge le jeu en ligne se fait attaquer. Maintenant, l’attaquant du site web possède votre email avec ce mot de passe. Il peut donc essayer votre mot de passe un peu partout. Sur PayPal par exemple.
+Bien, maintenant comment pouvons nous régler ce problèmes ?
+++Le bon, la brute et le truand
+
La méthode la plus courante est de se souvenir de plusieurs mot de passes différents. En général, si vous avez bonne mémoire vous pouvez mémoriser jusqu’à 13 mots de passes. Certain de bonne qualité, d’autre moins.
+Que faire si vous utilisez plus de services que vous pouvez mémoriser de mots de passe ?
+Un mauvaise solution peut être de choisir ses mots de passes de la façon suivante :
+P45sW0r|)TwitterP45sW0r|)gmailP45sW0r|)badonlinegameMalheureusement, si quelqu’un récupère votre mot de passe sur badonlinegame, il peut facilement retrouvez vos autres mots de passe. Bien sûr, on peut imaginer des transformation de mots de passe de meilleure qualité. Mais il est très difficile d’en trouver une suffisamment bonne.
Fort heureusement, il existe une des fonctions bien connues dans le milieu de la sécurité informatique et qui résolvent précisément ce problème. Il s’agit des fontions de hachages. Il est difficile de retrouver le paramètre d’entrée d’une fonction de hachage à partir de son résultat. Prenons un exemple :
+Si quelqu’un possède 9f00fd5dbba232b7c03afd2b62b5fce5cdc7df63, il va avoir de grande difficulté pour retrouver P45sW0r|).
Choisisson la fonction de hashage sha1. Connaissant celà, le mot de passe d’un site donné doit avoir la forme :
Où :
+master_password est votre unique mot de passe maître ;domain_name est le nom de domaine du site pour lequel vous voulez le mot de passe.Il faut aussi penser à certaines contraintes. Certains site web veulent des mots de passe d’une certaine longueur, ni trop longs ni trop courts. Que faire si vous voulez changez votre mot de passe ? Soit parce qu’il est compromis ou simplement parce qu’on vous impose de le changer. C’est pouquoi pour chaque site on a besoin de quelques paramètres supplémentaires.
+Selon ma situation, voici les outils que j’ai fait et que j’utilise :
+Quelquesoit mon environnement de travail, tous mes mots de passes sont à un copier/coller. Pour certain services, j’utilise des mots de passe de 40 caractères. Actuellement j’utilise plutôt des mots de passes de 10 caractères. Avec des mots de passes plus petit, il est encore plus difficile pour un attaquant de retrouver mon mot de passe principal.
+Je serai heureux de savoir ce que vous pensez de cette méthode. Alors n’hésitez pas à laisser un commentaire ou à m’envoyer un mail.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+tlpl: Comment déterminer de la façon la plus rationnelle possible le meilleur framework work relativement à vos besoins. Cliquez ici pour aller au résultats. Cet article n’est disponible qu’en anglais.
+This is it.
+You’ve got the next big idea.
+You just need to make a very simple web application.
It sounds easy! You just need to choose a good modern web framework, when suddenly:
+
+After your brain stack overflowed, you decide to use a very simple methodology. Answer two questions:
+Which language am I familiar with?
+What is the most popular web framework for this language?
Great! This is it.
+But, you continually hear this little voice.
+++“You didn’t made a bad choice, yes. But …
+
+you hadn’t made the best either.”
This article try to determine in the most objective and rational way the best(s) web framework(s) depending on your needs. To reach this goal, I will provide a decision tool in the result section.
+I will use the following methodology:
+Methodology
+++☞ Important Note
+
+I am far from happy to the actual result. There are a lot of biases, for example in the choice of the parameters. The same can be said about the data I gathered. I am using very imprecise informations. But, as far as I know, this is the only article which use many different parameters to help you choose a web framework.This is why I made a very flexible decision tool:
+ +
Here are the important features (properties/parameters) I selected to make the choice:
+Each feature is quite important and mostly independant from each other. I tried to embrace most important topics concerning web frameworks with these four properties. I am fully concious some people might lack another important feature. Nonetheless the methodology used here can be easily replicated. If you lack an important property add it at will and use this choice method.
+Also each feature is very hard to measure with precision. This is why we will only focus on order of magnitude.
+For each property a framework could have one of the six possible values: Excellent, Very Good, Good, Medium, Bad or Very Bad
+So how to make a decision model from these informations?
+One of the most versatile method is to give a weight for each cluster value. And to select the framework maximizing this score:
+score(framework) = efficiency + robustness + expressiveness + popularity++For example:
++ +
++ +Expressiveness +10 +7 +1 +-∞ +-∞ +-∞ ++ +Popularity +5 +5 +4 +3 +2 +1 ++ +Efficiency +10 +8 +6 +4 +2 +1 ++ + +Robustness +10 +8 +6 +4 +2 +1 +Using this weighted table, that means:
++
+- we discard the three least expressive clusters.
+- We don’t make any difference between excellent and very good in popularity.
+- Concerning efficient framework in excellent cluster will have 2 more points than the “very good” cluster.
+So for each framework we compute its score relatively to a weighted table. And we select the best(s).
+Example: Using this hypothetic framework and the preceeding table.
++ +
++ + + ++ Expressiveness +Popularity +Efficiency +Robustness ++ + +yog +Excellent +Very Bad +Medium +Very Good ++score(yog) = 10 + 0 + 4 + 8 = 22
Most needs should be expressed by such a weighted table. In the result section, we will discuss this further.
+It is now time to try to get these measures.
+None of the four properties I choosen can be measured with perfect precision. But we could get the order of magnitude for each.
+I tried to focus on the framework only. But it is often easier to start by studying the language first.
+For example, I have datas about popularity by language and I also have different datas concerning popularity by framework. Even if I use only the framework focused datas in my final decision model, it seemed important to me to discuss about the datas for the languages. The goal is to provide a tool to help decision not to give a decision for you.
+RedMonk Programming Language Rankings (January 2013) provide an apparent good measure of popularity. While not perfect the current measure feel mostly right. They create an image using stack overflow and github data. Vertical correspond to the number of questions on stackoverflow. Horizontal correspond to the number of projects on github.
+If you look at the image, your eye can see about four clusters. The 1st cluster correspond to mainstream languages:
+
+Most developer know at least one of these language.
+The second cluster is quite bigger. It seems to correspond to languages with a solid community behind them.
+
+I don’t get into detail, but you could also see third and fourth tier popular languages.
+So:
+Mainstream: JavaScript, Java, PHP, Python, Ruby, C#, C++, C, Objective-C, Perl, Shell
Good: Scala, Haskell, Visual Basic, Assembly, R, Matlab, ASP, ActionScript, Coffeescript, Groovy, Clojure, Lua, Prolog
+Medium: Erlang, Go, Delphi, D, Racket, Scheme, ColdFusion, F#, FORTRAN, Arduino, Tcl, Ocaml
+Bad: third tier Very Bad: fourth tier
+I don’t thing I could find easily web frameworks for third or fourth tier languages.
+For now, I only talked about language popularity. But what about framework popularity? I made a test using number of question on stackoverflow only. Then by dividing by two for each 6 cluster:
+| Cluster | +Language | +Framework | +#nb | +% | +
|---|---|---|---|---|
| Excellent | +Ruby | +Rails | +176208 | +100% | +
| Very Good | +Python | +Django | +57385 | +<50% | +
| + | Java | +Servlet | +54139 | ++ |
| + | Java | +Spring | +31641 | ++ |
| + | Node.js | +node.js | +27243 | ++ |
| + | PHP | +Codeigniter | +21503 | ++ |
| + | Groovy | +Grails | +20222 | ++ |
| Good | +Ruby | +Sinatra | +8631 | +<25% | +
| + | Python | +Flask | +7062 | ++ |
| + | PHP | +Laravel | +6982 | ++ |
| + | PHP | +Kohana | +5959 | ++ |
| + | Node.js | +Express | +5009 | ++ |
| Medium | +PHP | +Cake | +4554 | +<13% | +
| + | C♯ | +ServiceStack | +3838 | ++ |
| + | Scala | +Play | +3823 | ++ |
| + | Java | +Wicket | +3819 | ++ |
| + | Dart | +Dart | +3753 | ++ |
| + | PHP | +Slim | +3361 | ++ |
| + | Python | +Tornado | +3321 | ++ |
| + | Scala | +Lift | +2844 | ++ |
| + | Go | +Go | +2689 | ++ |
| Bad | +Java | +Tapestry | +1197 | +<6% | +
| + | C♯ | +aspnet | +1000 | ++ |
| + | Haskell | +Yesod | +889 | ++ |
| + | PHP | +Silex | +750 | ++ |
| + | PHP | +Lithium | +732 | ++ |
| + | C♯ | +nancy | +705 | ++ |
| Very bad | +Java | +Grizzly | +622 | +<3% | +
| + | Erlang | +Cowboy | +568 | ++ |
| + | Perl | +Dancer | +496 | ++ |
| + | PHP | +Symphony2 | +491 | ++ |
| + | Go | +Revel | +459 | ++ |
| + | Clojure | +Compojure | +391 | ++ |
| + | Perl | +Mojolicious | +376 | ++ |
| + | Scala | +Scalatra | +349 | ++ |
| + | Scala | +Finagle | +336 | ++ |
| + | PHP | +Phalcon | +299 | ++ |
| + | js | +Ringo | +299 | ++ |
| + | Java | +Gemini | +276 | ++ |
| + | Haskell | +Snap | +263 | ++ |
| + | Perl | +Plack | +257 | ++ |
| + | Erlang | +Elli | +230 | ++ |
| + | Java | +Dropwizard | +188 | ++ |
| + | PHP | +Yaf | +146 | ++ |
| + | Java | +Play1 | +133 | ++ |
| + | Node.js | +Hapi | +131 | ++ |
| + | Java | +Vertx | +60 | ++ |
| + | Scala | +Unfiltered | +42 | ++ |
| + | C | +onion | +18 | ++ |
| + | Clojure | +http-kit | +17 | ++ |
| + | Perl | +Kelp | +16 | ++ |
| + | PHP | +Micromvc | +13 | ++ |
| + | Lua | +Openresty | +8 | ++ |
| + | C++ | +cpoll-cppsp | +5 | ++ |
| + | Clojure | +Luminus | +3 | ++ |
| + | PHP | +Phreeze | +1 | ++ |
As we can see, our framework popularity indicator can be quite different from its language popularity. For now I didn’t found a nice way to merge the results from RedMonk with these one. So I’ll use these unperfect one. Hopefully the order of magninute is mostly correct for most framework.
+Another objective measure is efficiency. We all know benchmarks are all flawed. But they are the only indicators concerning efficiency we have.
+I used the benchmark from benchmarksgame. Mainly, there are five clusters:
+| 1x→2x | +C, C++ |
+
| 2x→3x | +Java 7, Scala, OCamL, Haskell, Go, Common LISP | +
| 3x→10x | +C♯, Clojure, Racket, Dart | +
| 10x→30x | +Erlang | +
| 30x→ | +PHP, Python, Perl, Ruby, JRuby | +
Remarks concerning some very slow languages:
+This is a first approach. The speed of the language for basic benchmarks. But, here we are interrested in web programming. Fortunately techempower has made some tests focused on most web frameworks:
+ +These benchmark doesn’t fit well with our needs. The values are certainly quite imprecise to your real usage. The goal is just to get an order of magnitude for each framework. Another problem is the high number of informations.
+As always, we should remember these informations are also imprecise. So I simply made some classes of efficiency.
+Remark: I separated the clusters by using power of 2 relatively to the fastest.
+| Cluster | +Language | +Framework | +#nb | +slowness | +
|---|---|---|---|---|
| Excellent | +C++ | +cpoll-cppsp | +114,711 | +1× | +
| + | Jav | +gemini | +105,204 | ++ |
| + | Lua | +openresty | +93,882 | ++ |
| + | Jav | +servlet | +90,580 | ++ |
| + | C++ | +cpoll-pool | +89,167 | ++ |
| + | Go | +go | +76,024 | ++ |
| + | Sca | +finagle | +68,413 | ++ |
| + | Go | +revel | +66,990 | ++ |
| + | Jav | +rest-express | +63,209 | ++ |
| Very Good | +Jav | +wicket | +48,772 | +>2× | +
| + | Sca | +scalatra | +48,594 | ++ |
| + | Clj | +http-kit | +42,703 | ++ |
| + | Jav | +spring | +36,643 | +>3× | +
| + | PHP | +php | +36,605 | ++ |
| + | Jav | +tapestry | +35,032 | ++ |
| + | Clj | +compojure | +32,088 | ++ |
| + | JS | +ringo | +31,962 | ++ |
| + | Jav | +dropwizard | +31,514 | ++ |
| + | Clj | +luminus | +30,672 | ++ |
| Good | +Sca | +play-slick | +29,950 | +>4× | +
| + | Sca | +unfiltered | +29,782 | ++ |
| + | Erl | +elli | +28,862 | ++ |
| + | Jav | +vertx | +28,075 | ++ |
| + | JS | +nodejs | +27,598 | ++ |
| + | Erl | +cowboy | +24,669 | ++ |
| + | C | +onion | +23,649 | ++ |
| + | Hkl | +yesod | +23,304 | ++ |
| + | JS | +express | +22,856 | +>5× | +
| + | Sca | +play-scala | +22,372 | ++ |
| + | Jav g | +rizzly-jersey | +20,550 | ++ |
| + | Py | +tornado | +20,372 | +>6× | +
| + | PHP | +phalcon | +18,481 | ++ |
| + | Grv | +grails | +18,467 | ++ |
| + | Prl | +plack | +16,647 | +>7× | +
| + | PHP | +yaf | +14,388 | ++ |
| Medium | +JS | +hapi | +11,235 | +>10× | +
| + | Jav | +play1 | +9,979 | ++ |
| + | Hkl | +snap | +9,196 | ++ |
| + | Prl | +kelp | +8,250 | ++ |
| + | Py | +flask | +8,167 | ++ |
| + | Jav | +play-java | +7,905 | ++ |
| + | Jav p | +lay-java-jpa | +7,846 | ++ |
| + | PHP | +micromvc | +7,387 | ++ |
| + | Prl | +dancer | +5,040 | +>20× | +
| + | Prl | +mojolicious | +4,371 | ++ |
| + | JS | +ringo-conv | +4,249 | ++ |
| + | Py | +django | +4,026 | ++ |
| + | PHP | +codeigniter | +3,809 | +>30× | +
| Bad | +Rby | +rails | +3,445 | ++ |
| + | Sca | +lift | +3,311 | ++ |
| + | PHP | +slim | +3,112 | ++ |
| + | PHP | +kohana | +2,378 | +>40× | +
| + | PHP | +silex | +2,364 | ++ |
| Very Bad | +PHP | +laravel | +1,639 | +>60× | +
| + | PHP | +phreeze | +1,410 | ++ |
| + | PHP | +lithium | +1,410 | ++ |
| + | PHP | +fuel | +1,410 | ++ |
| + | PHP | +cake | +1,287 | +>80× | +
| + | PHP | +symfony2 | +879 | +>100× | +
| + | C# | +aspnet-mvc | +871 | ++ |
| + | Rby | +sinatra | +561 | +>200× | +
| + | C# | +servicestack | +51 | ++ |
| + | Dar | +dart | +0 | ++ |
| + | C# | +nancy | +0 | ++ |
| + | Prl | +web-simple | +0 | ++ |
These are manually made clusters. But you get the idea. Certainly, some framework could jump between two different clusters. So this is something to remember. But as always, the order of magnitude is certainly mostly right.
+Now, how to objectively measure expressiveness?
+RedMonk had a very good idea to find an objective (while imprecise) measure of each language expressiveness. Read this article for details.
+After filtering languages suitable for web development, we end up with some clusters:
+| Cluster | +Languages | +
|---|---|
| Excellent | +Coffeescript, Clojure, Haskell | +
| Very Good | +Racket, Groovy, R, Scala, OCamL, F♯, Erlang, Lisp, Go | +
| Medium | +Perl, Python, Objective-C, Scheme, Tcl, Ruby | +
| Bad | +Lua, Fortran (free-format), PHP, Java, C++, C♯ | +
| Very Bad | +Assembly, C, Javascript, | +
Unfortunately there is no information about dart. So I simply give a very fast look at the syntax. As it looked a lot like javascript and js is quite low. I decided to put it close to java.
+Also an important remark, javascript score very badly here while coffeescript (compiling to js) score “excellent”. So if you intend to use a javascript framework but only with coffescript that should change substantially the score. As I don’t believe it is the standard. Javascript oriented framework score very badly regarding expressiveness.
+| Cluster | +Language | +Framework | +
|---|---|---|
| Excellent | +Clj | +luminus | +
| + | Clj | +http-kit | +
| + | Clj | +compojure | +
| + | Hkl | +snap | +
| + | Hkl | +yesod | +
| Very Good | +Erl | +elli | +
| + | Erl | +cowboy | +
| + | Go | +go | +
| + | Go | +revel | +
| + | Grv | +grails | +
| + | Sca | +lift | +
| + | Sca | +finagle | +
| + | Sca | +scalatra | +
| + | Sca | +play-scala | +
| + | Sca | +play-slick | +
| + | Sca | +unfiltered | +
| Medium | +Prl | +kelp | +
| + | Prl | +plack | +
| + | Prl | +dancer | +
| + | Prl | +web-simple | +
| + | Prl | +mojolicious | +
| + | Py | +flask | +
| + | Py | +django | +
| + | Py | +tornado | +
| + | Rby | +rails | +
| + | Rby | +sinatra | +
| Bad | +C# | +nancy | +
| + | C# | +aspnet-mvc | +
| + | C# | +servicestack | +
| + | C++ | +cpoll-pool | +
| + | C++ | +cpoll-cppsp | +
| + | Dar | +dart | +
| + | Jav | +play1 | +
| + | Jav | +vertx | +
| + | Jav | +gemini | +
| + | Jav | +spring | +
| + | Jav | +wicket | +
| + | Jav | +servlet | +
| + | Jav | +tapestry | +
| + | Jav | +play-java | +
| + | Jav | +dropwizard | +
| + | Jav | +rest-express | +
| + | Jav | +play-java-jpa | +
| + | Jav | +grizzly-jersey | +
| + | Lua | +openresty | +
| + | PHP | +php | +
| + | PHP | +yaf | +
| + | PHP | +cake | +
| + | PHP | +fuel | +
| + | PHP | +slim | +
| + | PHP | +silex | +
| + | PHP | +kohana | +
| + | PHP | +laravel | +
| + | PHP | +lithium | +
| + | PHP | +phalcon | +
| + | PHP | +phreeze | +
| + | PHP | +micromvc | +
| + | PHP | +symfony2 | +
| + | PHP | +codeigniter | +
| Very Bad | +C | +onion | +
| + | JS | +hapi | +
| + | JS | +ringo | +
| + | JS | +nodejs | +
| + | JS | +express | +
| + | JS | +ringo-conv | +
I couldn’t find any complete study to give the number of bug relatively to each framework/language.
+But one thing I saw from experience is the more powerful the type system the safest your application is. While the type system doesn’t remove completely the need to test your application a very good type system tend to remove complete classes of bug.
+Typically, not using pointer help to reduce the number of bugs due to bad references. Also, using a garbage collector, reduce greatly the probability to access unallocated space.
+
+From my point of view, robustness is mostly identical to safety.
+Here are the clusters:
+| Excellent | +Haskell, Scheme, Erlang | +
| Very Good | +Scala, Java, Clojure | +
| Good | +Ruby, Python, Groovy, javascript, PHP | +
| Medium | +C++, C#, Perl, Objective-C, Go, C | +
So applying this to frameworks gives the following clusters:
+| Cluster | +Language | +Framework | +
|---|---|---|
| Excellent | +Erl | +elli | +
| + | Erl | +cowboy | +
| + | Hkl | +snap | +
| + | Hkl | +yesod | +
| Very Good | +Clj | +luminus | +
| + | Clj | +http-kit | +
| + | Clj | +compojure | +
| + | Jav | +play1 | +
| + | Jav | +vertx | +
| + | Jav | +gemini | +
| + | Jav | +spring | +
| + | Jav | +wicket | +
| + | Jav | +servlet | +
| + | Jav | +tapestry | +
| + | Jav | +play-java | +
| + | Jav | +dropwizard | +
| + | Jav | +rest-express | +
| + | Jav | +play-java-jpa | +
| + | Jav | +grizzly-jersey | +
| + | Sca | +lift | +
| + | Sca | +finagle | +
| + | Sca | +scalatra | +
| + | Sca | +play-scala | +
| + | Sca | +play-slick | +
| + | Sca | +unfiltered | +
| Good | +Grv | +grails | +
| + | JS | +hapi | +
| + | JS | +ringo | +
| + | JS | +nodejs | +
| + | JS | +express | +
| + | JS | +ringo-conv | +
| + | Lua | +openresty | +
| + | PHP | +php | +
| + | PHP | +yaf | +
| + | PHP | +cake | +
| + | PHP | +fuel | +
| + | PHP | +slim | +
| + | PHP | +silex | +
| + | PHP | +kohana | +
| + | PHP | +laravel | +
| + | PHP | +lithium | +
| + | PHP | +phalcon | +
| + | PHP | +phreeze | +
| + | PHP | +micromvc | +
| + | PHP | +symfony2 | +
| + | PHP | +codeigniter | +
| + | Py | +flask | +
| + | Py | +django | +
| + | Py | +tornado | +
| + | Rby | +rails | +
| + | Rby | +sinatra | +
| Medium | +C | +onion | +
| + | C# | +nancy | +
| + | C# | +aspnet-mvc | +
| + | C# | +servicestack | +
| + | C++ | +cpoll-pool | +
| + | C++ | +cpoll-cppsp | +
| + | Dar | +dart | +
| + | Go | +go | +
| + | Go | +revel | +
| + | Prl | +kelp | +
| + | Prl | +plack | +
| + | Prl | +dancer | +
| + | Prl | +web-simple | +
| + | Prl | +mojolicious | +
For the result I initialized the table with my own needs.
+And I am quite happy it confirms my current choice. I sware I didn’t given yesod any bonus point. I tried to be the most objective and factual as possible.
+Now, it is up to you to enter your preferences.
+On each line you could change how important a feature is for you. From essential to unsignificant. Of course you could change the matrix at will.
+I just show a top 10 frameworks. In order to give a more understandable measure I provide the log of the score.
+| + | ++Excellent + | ++Very good + | ++Good + | ++Medium + | ++Bad + | ++Very bad + | ++Importance + | +
|---|---|---|---|---|---|---|---|
| +Expressiveness + | +|||||||
| +Popularity + | +|||||||
| +Efficiency + | +|||||||
| +Robustness + | +
I didn’t had the courage in explaining in what the scoring system is good. Mostly, if you use product instead of sum for the score you could use power of e for the values in the matrix. And you could see the matrix as a probability matrix (each line sum to 1). Which provide a slighly better intuition on whats going on.
+Remember only that values are exponential. Do not double an already big value for example the effect would be extreme.
+All of this is based as most as I could on objective data. The choice method seems both rather rational and classical. It is now up to you to edit the score matrix to set your needs.
+I know that in the current state there are many flaws. But it is a first system to help make a choice rationally.
+I encourage you to go further if you are not satisfied by my method.
+The source code for the matrix shouldn’t be too hard to read. Just read the source of this webpage. You could change the positionning of some frameworks if you believe I made some mistake by placing them in some bad clusters.
+So I hope this tool will help you in making your life easier.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+tlpl: Utiliser m4 pour accroître le pouvoir d’xslt et d’svg. Example cool, les fractales.
+Lorsqu’xml fût inventé beaucoup pensaient que c’était l’avenir. Passer de fichiers plat à des fichiers structurés standardisés fût un grand progrès dans beaucoup de domaines. Cerain se mirent à voir du xml de partout. À tel point que les les format compatibles xml naquirent de toute part. Non seulement comme format de fichier, mais aussi comme format pour un langage de programmation.
+Ô joie !
+Malheureusement, xml fût fabriquer pour le transfert de données. Pas du tout pour être vu ou édité directement. La triste vérité est qu’xml est verbeux et laid. Dans un monde parfait, nous ne devrions avoir des programmes qui s’occupent de nous afficher correctement le xml pour nous épargner la peine de les voir directement. Mais devinez quoi ? Notre monde n’est pas parfait. Beaucoup de programmeurs sont ainsi forcé de travailler directement avec de l’xml.
+xml, n’est pas le seul cas de format mal utilisé que je connaisse. Vous avez d’autres formats dans lesquels il serait très agréable d’ajouter des variables, des boucles, des fonctions…
+Mais je suis là pour vous aider. Si comme moi vous détestez xslt ou écrire de l’xml. Je vais vous montrer une façon d’améliorer tout ça.
+Commençons avec le pire cas de langage xml que je connaisse : xslt. Tous les développeurs qui ont déjà dû écrire du xslt savent à quel point ce langage est horrible.
+Pour réduire la “verbosité” de tels langages, il y a un moyen. m4. Oui, le préprocesseur utilisé par C et C++.
Voici certains exemples :
+myvar = value, voici la version print "Hello world!", print myvar, nous avons droit à :<?xml version="1.0" standalone="yes"?> <!-- YES its <span class="sc">xml</span> -->
+<!-- ← start a comment, then write some m4 directives:
+
+define(`ydef',`<xsl:variable name="$1" select="$2"/>')
+define(`yprint',`<xsl:text disable-output-escaping="yes"><![CDATA[$1]]></xsl:text>')
+define(`yshow',`<xsl:value-of select="$1"/>')
+
+-->
+<!-- Yes, <span class="sc">xml</span> sucks to be read -->
+<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
+<!-- And it sucks even more to edit -->
+<xsl:template match="/">
+ ydef(myvar,value)
+ yprint(Hello world!)
+ yshow(myvar)
+</xsl:template>Maintenant compilons simplement ce fichier :
+ +Et vous pouvez profitez ! Maintenant
À ses débuts, beaucoup pensaient que ce serait le nouveau Flash. Apparemment, ce devrait plutôt être canvas avec du javascript qui occupera cette place.
Tout d’abord, laissez moi vous montrer le résultat :
+ +
+Cliquez sur l’image pour voir le svg directement. Attention, si vous n’avez pas un ordinateur récent, ça risque de ramer.
+Le positionnement du texte “esod” par rapport au “λ” renversé a été en jouant avec firebug. De cette façon je n’avais pas à regénérer pour tester.
+Faire une telle fractale revient à :
+Si j’avais dû faire ça manuellement, il m’aurait fallu faire beaucoup de copier/coller dans mon svg. Simplement parce que la transformation est toujours la même, mais je ne pouvais pas dire, utiliser la transformation appelée “titi”. Plutôt que copier du xml, j’ai utilisé m4.
+Et voici le code commenté :
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!--
+ M4 Macros
+define(`YTRANSFORMONE', `scale(.43) translate(-120,-69) rotate(-10)')
+define(`YTRANSFORMTWO', `scale(.43) translate(-9,-67.5) rotate(10)')
+define(`YTRANSFORMTHREE', `scale(.43) translate(53,41) rotate(120)')
+define(`YGENTRANSFORM', `translate(364,274) scale(3)')
+define(`YTRANSCOMPLETE', `
+ <g id="level_$1">
+ <use style="opacity: .8" transform="YTRANSFORMONE" xlink:href="#level_$2" />
+ <use style="opacity: .8" transform="YTRANSFORMTWO" xlink:href="#level_$2" />
+ <use style="opacity: .8" transform="YTRANSFORMTHREE" xlink:href="#level_$2" />
+ </g>
+ <use transform="YGENTRANSFORM" xlink:href="#level_$1" />
+')
+ -->
+<svg
+ xmlns="http://www.w3.org/2000/svg"
+ xmlns:xlink="http://www.w3.org/1999/xlink"
+ x="64" y="64" width="512" height="512" viewBox="64 64 512 512"
+ id="svg2" version="1.1">
+ <g id="level_0"> <!-- some group, if I want to add other elements -->
+ <!-- the text "λ" -->
+ <text id="lambda"
+ fill="#333" style="font-family:Ubuntu; font-size: 100px"
+ transform="rotate(180)">λ</text>
+ </g>
+ <!-- the text "esod" -->
+ <text
+ fill="#333"
+ style="font-family:Ubuntu; font-size: 28px; letter-spacing: -0.10em"
+ x="-17.3"
+ y="69"
+ transform="YGENTRANSFORM">esod</text>
+ <!-- ROOT ELEMENT -->
+ <use transform="YGENTRANSFORM" xlink:href="#level_0" />
+
+ YTRANSCOMPLETE(1,0) <!-- First recursion -->
+ YTRANSCOMPLETE(2,1) <!-- deeper -->
+ YTRANSCOMPLETE(3,2) <!-- deeper -->
+ YTRANSCOMPLETE(4,3) <!-- even deeper -->
+ YTRANSCOMPLETE(5,4) <!-- Five level seems enough -->
+</svg>et je l’ai compile en
Le λ est dupliqué avec trois “transformations” différentes. Les transformations sont : YTRANSFORMONE, YTRANSFORMTWO et YTRANSFORMTHREE.
Chaque transformation est une similarité (translation + rotation + zoom, ce qui est équivalent à juste rotation + zoom, mais bon).
+Une fois fixée chaque transformation peut ensuite être réutilisée pour chaque nouveau niveau.
+Maintenant YTRANSCOMPLETE entre en jeu. Cette macro prend deux arguments. Le niveau courant et le niveau précédent. Cette macro va dupliquer le niveau précédent en lui appliquant chacune des 3 transformations. Au niveau 0, le contenu est un seul grand λ, le niveau 1 en contient 3. Le niveau 2 en contient 9, etc… Le niveau 5 contient 35=243 λ. Tous les niveaux combinés représentent 36-1 / 2 = 364 λ.
L’avantage principal c’est que je pouvais visualiser le résultat final facilement. Sans ce système de macro, pour faire une preview il m’aurait fallu faire des copier/coller + quelques modifications à chaque essai.
+Ce fut très amusant de faire une fractale en
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+tlpl: Pour installer Haskell (OS X et Linux) copiez/collez les lignes suivante dans un terminal :
+curl https://raw.githubusercontent.com/yogsototh/install-haskell/master/install-haskell.sh | sudo zshSi vous êtes sous windows, téléchargez Haskell Platform et suivez les instructions pour utiliser Haskell LTS.
+Si vous voulez savoir le pourquoi et le comment ; lisez le reste de l’article.
+La plus grande faiblesse d’Haskell n’a rien à voir avec le langage en lui-même mais avec son écosystème.
+The main problem I’ll try to address is the one known as cabal hell. The community is really active in fixing the issue. I am very confident that in less than a year this problem will be one of the past. But to work today, I provide an install method that should reduce greatly two effects of cabal hell:
+With my actual installation method, you should minimize your headache and almost never hit a dependency error. But there could exists some. If you encounter any dependency error, ask gently to the package manager to port its package to stackage.
+So to install copy/paste the following three lines in your terminal:
+curl https://raw.githubusercontent.com/yogsototh/install-haskell/master/install-haskell.sh | sudo zshYou can read the script and you will see that this is quite straightforward.
+GHC binary for you system and install it.cabal program.As the version of libraries is fixed up until you update the Haskell LTS version, you should never use cabal sandbox. That way, you will only compile each needed library once. The compiled objects/binaries will be in your ~/.cabal directory.
This script use the latest Haskell LTS. So if you use this script at different dates, the Haskell LTS might have changed.
+While it comes to cabal hell, some solutions are sandboxes and nix. Unfortunately, sandboxes didn’t worked good enough for me after some time. Furthermore, sandboxes forces you to re-compile everything by project. If you have three yesod projects for example it means a lot of time and CPU. Also, nix didn’t worked as expected on OS X. So fixing the list of package to a stable list of them seems to me the best pragmatic way to handle the problem today.
From my point of view, Haskell LTS is the best step in the right direction. The actual cabal hell problem is more a human problem than a tool problem. This is a bias in most programmer to prefer resolve social issues using tools. There is nothing wrong with hackage and cabal. But for a package manager to work in a static typing language as Haskell, packages must work all together. This is a great strength of static typed languages that they ensure that a big part of the API between packages are compatible. But this make the job of package managing far more difficult than in dynamic languages.
+People tend not to respect the rules in package numbering1. They break their API all the time. So we need a way to organize all of that. And this is precisely what Haskell LTS provide. A set of stable packages working all together. So if a developer break its API, it won’t work anymore in stackage. And whether the developer fix its package or all other packages upgrade their usage. During this time, Haskell LTS end-users will be able to develop without dependency issues.
++The image of the cat about to jump that I slightly edited can found here +
+I myself am guilty of such behavior. It was a beginner error.↩
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+tlpl: Les boutons des réseaux sociaux traquent vos utilisateurs, ont un design incohérent avec celui de votre site, utilisent des ressources, ralentissent le rendu de vos pages.
+Faite les choses bien. Utilisez des liens statiques.
+Si vous n’avez pas envie de lire, copiez et collez simplement le code suivant dans votre html :
+<div id="sociallinks">
+ <a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Tweet this</a> -
+ <a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Like this</a> -
+ <a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Share on G+</a>
+</div>
+<script>
+(function(){window.addEventListener("DOMContentLoaded",function(){
+ var url=document.location;
+ var links=document.getElementById("sociallinks")
+ .getElementsByTagName('a');
+ for (var i=0;i!=links.length;i++){
+ links[i].setAttribute("href",
+ links[i].href.replace('$url$',url));}})})();
+</script>Ever been on a website and want to tweet about it? Fortunately, the website might have a button to help you. But do you really know what this button do?
+The “Like”, “Tweet” and “+1” buttons will call a javascript. It will get access to your cookies. It helps the provider of the button to know who you are.
+In plain English, the “+1” button will inform Google you are visiting the website, even if you don’t click on “+1”. The same is true for the “like” button for facebook and the “tweet this” button for twitter.
+The problem is not only a privacy issue. In fact (sadly imho) this isn’t an issue for most people. These button consume computer ressources. Far more than a simple link. It thus slow down a bit the computer and consume energy. These button could also slow down the rendering of your web page.
+Another aspect is their design. Their look and feel is mostly imposed by the provider.
+The most problematic aspect in my opinion is to use a third party js on your website. What if tomorrow twitter update their tweet button? If the upgrade break something for only a minority of people, they won’t fix it. This could occur anytime without any notification. They just have to add a document.write in their js you call asynchronously and BAM! Your website is just an empty blank page. And as you call many external ressources, it can be very difficult to find the origin of the problem.
Using social network buttons:
+I will provide you two solutions with the following properties:
+Solution 1 (no js):
+<a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Tweet this</a>
+
+<a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Like this</a>
+
+<a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Share on G+</a>But you have to replace $url$ by the current url.
Solution 2 (Just copy/paste):
+If you don’t want to write the url yourself, you could use some minimal js:
+<div id="sociallinks">
+ <a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Tweet this</a> -
+ <a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Like this</a> -
+ <a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Share on G+</a>
+</div>
+<script>
+(function(){window.addEventListener("DOMContentLoaded",function(){
+ var url=document.location;
+ var links=document.getElementById("sociallinks")
+ .getElementsByTagName('a');
+ for (var i=0;i!=links.length;i++){
+ links[i].setAttribute("href",
+ links[i].href.replace('$url$',url));}})})();
+</script>Here is the result:
+If you don’t want just text but nice icons. You have many choices:
+<img src="..."/> in the links.As the first solution is pretty straightforward, I’ll explain the second one.
+@font-face
+ font-family: 'social'
+ src: url('fonts/social_font.ttf') format('truetype')
+ font-weight: normal
+ font-style: normal
+.social
+ font-family: socialNow add this to your html:
+Solution 1 (without js):
+<a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">t</a>
+·
+<a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">`</a>
+·
+<a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">g</a>Solution 2 (same with a bit more js):
+<div id="sociallinksunicode">
+<a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">t</a>
+·
+<a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">`</a>
+·
+<a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">g</a>
+</div>
+<script>
+(function(){window.addEventListener("DOMContentLoaded",function(){
+ var url=document.location;
+ var links=document.getElementById("sociallinksunicode")
+ .getElementsByTagName('a');
+ for (var i=0;i!=links.length;i++){
+ links[i].setAttribute("href",
+ links[i].href.replace('$url$',url));}})})();
+</script>Here is the result:
+ps: On my personal website I continue to use Google analytics. Therefore, Google (and only Google, not facebook nor twitter) can track you here. But I might change this in the future.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+tlpl: La typography sur le web est pourrie et nous ne somme pas près de voir ce problème réparé.
+Je suis tombé sur ce site: open typography. Leur message principal est :
+++«There is no reason to wait for browser development to catch up. We can all create better web typography ourselves, today.»
+
ou en français :
+++«Nous ne somme pas obligé d’attendre le développement des navigateurs. Nous pouvons créer un web avec une meilleure typographie aujourd’hui.»
+
Comme quelqu’un qui a déjà essayé d’améliorer la typographie de son site web, et en particulier des ligatures, je crois que c’est faux.
+J’ai déjà écrit un système automatique qui détecte et ajoute des ligatures en utilisant des caractères unicode. Cependant je n’ai jamais publié cette amélioration sur le web et voilà pourquoi :
+Tout d’abord, qu’est-ce qu’un ligature ?
+
+Quel est le problème des ligatures sur le web ? Le premier c’est que vous ne pouvez pas chercher les mots qui contiennent ces ligatures. Par exemple essayez de chercher le mot “first”.
+C-f).Le second problème est le rendu. Par exemple, essayer d’utiliser un charactère de ligature en petites capitales :
+Voici une capture d’écran pour que vous voyez ce que je vois :
+
+Le navigateur est incapable de comprendre que le caractère de ligature “fi” doit être rendu comme
Comment par exemple utiliser un charactère de ligature unicode sur un site qui possède différents rendus via différentes css ?
+Comparons à LaTeX
+
+Si vous faites attention au détail, vous constaterez que le premier “first” contient une ligature. Bien entendu la deuxième ligne est affichée correctement. Le code que j’ai utilisé pour avoir ce rendu est simplement :
+ +LaTeX a été suffisamment intelligent pour créer les ligatures si nécessaire.
+La ligature “st” est rare et n’est pas rendu par défaut par LaTeX. Si vous voulez voir des ligatures rares, vous pouvez utiliser XƎLaTeX:
+
+J’ai copié cette image de l’excellent article de Dario Taraborelli.
+Clairement il sera difficile aux navigateurs de corriger ces problèmes. Imaginez le nombre de petites exceptions.
+Dans tous les cas, si quelqu’un possède une solution je suis preneur !
+En réalité, vous devriez pouvoir voir une ligature. Maintenant j’utilise : text-rendering: optimizelegibility. Le rendu est correct parce que j’utilise une fonte correct, à savoir Computer Modern de Donald Knuth.↩
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+tlpl: Comment utiliser vim comme une IDE très efficace
+In Learn Vim Progressively I’ve show how Vim is great for editing text, and navigating in the same file (buffer). In this short article you’ll see how I use Vim as an IDE. Mainly by using some great plugins.
+There are a lot of Vim plugins. To manage them I use vim-plug.
To install it:
+mkdir -p ~/.vim/autoload
+curl -fLo ~/.vim/autoload/plug.vim \
+ https://raw.githubusercontent.com/junegunn/vim-plug/master/plug.vim☞ Note I have two parts in my .vimrc. The first part contains the list of all my plugins. The second part contains the personal preferences I setted for each plugin. I’ll separate each part by ... in the code.
+Before anything, you should protect your eyes using a readable and low contrast colorscheme.
+For this I use solarized dark. To add it, you only have to write this in your ~/.vimrc file:
call plug#begin('~/.vim/plugged')
+
+Plug 'altercation/vim-colors-solarized'
+
+call plug#end()
+
+" -- solarized personal conf
+set background=dark
+try
+ colorscheme solarized
+catch
+endtryYou should be able to see and destroy trailing whitespaces.
+
+Plug 'bronson/vim-trailing-whitespace'You can clean trailing whitespace with :FixWhitespace.
And also you should see your 80th column.
+if (exists('+colorcolumn'))
+ set colorcolumn=80
+ highlight ColorColumn ctermbg=9
+endifOne of the most important hidden skills in programming is the ability to search and find files in your projects.
+The majority of people use something like NERDTree. This is the classical left column with a tree of files of your project. I stopped to use this. And you should probably too.
I switched to unite. No left column lost. Faster to find files. Mainly it works like Spotlight on OS X.
+First install ag (the silver search). If you don’t know ack or ag your life is going to be upgraded. This is a simple but essential tool. It is mostly a grep on steroids.
" Unite
+" depend on vimproc
+" ------------- VERY IMPORTANT ------------
+" you have to go to .vim/plugin/vimproc.vim and do a ./make
+" -----------------------------------------
+Plug 'Shougo/vimproc.vim'
+Plug 'Shougo/unite.vim'
+
+...
+
+let g:unite_source_history_yank_enable = 1
+try
+ let g:unite_source_rec_async_command='ag --nocolor --nogroup -g ""'
+ call unite#filters#matcher_default#use(['matcher_fuzzy'])
+catch
+endtry
+" search a file in the filetree
+nnoremap <space><space> :split<cr> :<C-u>Unite -start-insert file_rec/async<cr>
+" reset not it is <C-l> normally
+:nnoremap <space>r <Plug>(unite_restart)Now type space twice. A list of files appears. Start to type some letters of the file you are searching for. Select it, type return and bingo the file opens in a new horizontal split.
+
+If something goes wrong just type <space>r to reset the unite cache.
Now you are able to search file by name easily and efficiently.
+Now search text in many files. For this you use ag:
Plug 'rking/ag.vim'
+...
+" --- type ° to search the word in all files in the current dir
+nmap ° :Ag <c-r>=expand("<cword>")<cr><cr>
+nnoremap <space>/ :AgDon’t forget to add a space after the :Ag.
These are two of the most powerful shortcut for working in a project. using ° which is nicely positioned on my azerty keyboard. You should use a key close to *.
So what ° is doing? It reads the string under the cursor and search for it in all files. Really useful to search where a function is used.
If you type <space>/ followed by a string, it will search for all occurrences of this string in the project files.
So with this you should already be able to navigate between files very easily.
+
+Show which line changed since your last commit.
+Plug 'airblade/vim-gitgutter'And the “defacto” git plugin:
+Plug 'tpope/vim-fugitive'You can reset your changes from the latest git commit with :Gread. You can stage your changes with :Gwrite.
+Plug 'junegunn/vim-easy-align'
+
+...
+
+" Easy align interactive
+vnoremap <silent> <Enter> :EasyAlign<cr>Just select and type Return then space. Type Return many type to change the alignments.
If you want to align the second column, Return then 2 then space.
+C-n & C-pVim has a basic auto completion system. The shortcuts are C-n and C-p while you are in insert mode. This is generally good enough in most cases. For example when I open a file not in my configured languages.
My current Haskell programming environment is great!
+Each time I save a file, I get a comment pointing to my errors or proposing me how to improve my code.
+So here we go:
+++☞ Don’t forget to install
+ghc-modwith:cabal install ghc-mod
" ---------- VERY IMPORTANT -----------
+" Don't forget to install ghc-mod with:
+" cabal install ghc-mod
+" -------------------------------------
+
+Plug 'scrooloose/syntastic' " syntax checker
+" --- Haskell
+Plug 'yogsototh/haskell-vim' " syntax indentation / highlight
+Plug 'enomsg/vim-haskellConcealPlus' " unicode for haskell operators
+Plug 'eagletmt/ghcmod-vim'
+Plug 'eagletmt/neco-ghc'
+Plug 'Twinside/vim-hoogle'
+Plug 'pbrisbin/html-template-syntax' " Yesod templates
+
+...
+
+" -------------------
+" Haskell
+" -------------------
+let mapleader="-"
+let g:mapleader="-"
+set tm=2000
+nmap <silent> <leader>ht :GhcModType<CR>
+nmap <silent> <leader>hh :GhcModTypeClear<CR>
+nmap <silent> <leader>hT :GhcModTypeInsert<CR>
+nmap <silent> <leader>hc :SyntasticCheck ghc_mod<CR>:lopen<CR>
+let g:syntastic_mode_map={'mode': 'active', 'passive_filetypes': ['haskell']}
+let g:syntastic_always_populate_loc_list = 1
+nmap <silent> <leader>hl :SyntasticCheck hlint<CR>:lopen<CR>
+
+" Auto-checking on writing
+autocmd BufWritePost *.hs,*.lhs GhcModCheckAndLintAsync
+
+" neocomplcache (advanced completion)
+autocmd BufEnter *.hs,*.lhs let g:neocomplcache_enable_at_startup = 1
+function! SetToCabalBuild()
+ if glob("*.cabal") != ''
+ set makeprg=cabal\ build
+ endif
+endfunction
+autocmd BufEnter *.hs,*.lhs :call SetToCabalBuild()
+
+" -- neco-ghc
+let $PATH=$PATH.':'.expand("~/.cabal/bin")Just enjoy!
+
+I use - for my leader because I use , a lot for its native usage.
-ht will highlight and show the type of the block under the cursor.-hT will insert the type of the current block.-hh will unhighlight the selection.
+
+My main language at work is Clojure. And my current vim environment is quite good. I lack the automatic integration to lein-kibit thought. If I have the courage I might do it myself one day. But due to the very long startup time of clojure, I doubt I’ll be able to make a useful vim plugin.
So mainly you’ll have real rainbow-parenthesis (the default values are broken for solarized).
+I used the vim paredit plugin before. But it is too restrictive. Now I use sexp which feel more coherent with the spirit of vim.
" " -- Clojure
+Plug 'kien/rainbow_parentheses.vim'
+Plug 'guns/vim-clojure-static'
+Plug 'guns/vim-sexp'
+Plug 'tpope/vim-repeat'
+Plug 'tpope/vim-fireplace'
+
+...
+
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl RainbowParenthesesActivate
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl RainbowParenthesesLoadRound
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl RainbowParenthesesLoadSquare
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl RainbowParenthesesLoadBraces
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl setlocal iskeyword+=?,-,*,!,+,/,=,<,>,.,:
+" -- Rainbow parenthesis options
+let g:rbpt_colorpairs = [
+ \ ['darkyellow', 'RoyalBlue3'],
+ \ ['darkgreen', 'SeaGreen3'],
+ \ ['darkcyan', 'DarkOrchid3'],
+ \ ['Darkblue', 'firebrick3'],
+ \ ['DarkMagenta', 'RoyalBlue3'],
+ \ ['darkred', 'SeaGreen3'],
+ \ ['darkyellow', 'DarkOrchid3'],
+ \ ['darkgreen', 'firebrick3'],
+ \ ['darkcyan', 'RoyalBlue3'],
+ \ ['Darkblue', 'SeaGreen3'],
+ \ ['DarkMagenta', 'DarkOrchid3'],
+ \ ['Darkblue', 'firebrick3'],
+ \ ['darkcyan', 'SeaGreen3'],
+ \ ['darkgreen', 'RoyalBlue3'],
+ \ ['darkyellow', 'DarkOrchid3'],
+ \ ['darkred', 'firebrick3'],
+ \ ]Working with Clojure will becomre quite smoother. You can eval any part of your code, you must launch a Clojure REPL manually in another terminal thought.
+I hope it will be useful.
+Last but not least, if you want to use my vim configuration you can get it here:
+ +
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+tlpl:
+Cela fait un moment que je suis la progression du framework yesod. À mon humble avis on peut commencer à l’utiliser pour des applications sérieuses (comprendre en prod). Avant de vous dire pourquoi vous devriez aussi le considérer, je préfère vous parler de bonnes idées (parmi d’autres) introduites par yesod que je n’avais jamais vu ailleurs.
+Commençons par une BD d’xkcd :
+Lorsque vous créez une application web, beaucoup de temps est passé à s’occuper de chaînes de caractères. Des chaînes de caractère pour les URL, le HTML, le Javascript, les CSS, les requêtes SQL, etc… Pour éviter des utilisation malicieuses vous devez protéger chaque chaîne de caractère entre chaque étape. Par exemple supposons que vous entriez comme nom :
+ +Sans une protection correcte, le message “An apple fall” sera affiché à chaque fois que quelqu’un essayera d’accéder au nom de cet utilisateur. Les “types saufs” sont le tonyglandil du web. A chaque chaine de caractère, on lui associe un “type”. A quoi sert cette chaîne de caractère ? Est-ce une URL ? Du javascript ? De l’HTML ? Entre chaque passage d’une représentation à une autre, un transformation is faite par défaut.
+Yesod fait de son mieux pour typer les objets manipulés et ainsi il fera ce qu’il faut pour ne pas mettre du script dans une URL par exemple.
+ +Comme AnotherPageR est une URL elle ne pourra contiendra pas (par défaut) de caractère dangereux comme par exemple :
Les widgets de yesod sont différents des widgets Javascripts (ou java). Pour yesod un widget est un ensemble de morceaux d’appli web. Et si dans une page on veut utiliser plusieurs widgets, alors yesod s’occupe de tout. Des exemples de widgets (au sens yesod) sont :
+Pour chacun de ces widgets vous pourriez avoir besoin d’
+Certain morceau doivent être placés dans le «header» de la page et d’autre dans le «body».
+Vous pouvez déclarer un widget comme suit (je n’utilise pas la vrai syntaxe) :
+htmlheader = ...
+cssheader = ...
+javascriptheader = ...
+htmlbody = ...La vraie syntaxe est :
+toWidgetHeader cassiusFile "button.cassius"
+toWidgetHeader juliusFile "button.julius"
+toWidget hamletFile "buttonTemplate.hamlet"Veuillez aussi noté la convention Shakespearienne des noms. Encore une bonne raison d’utiliser yesod.
+Lorsque vous générez votre page, yesod se débrouille pour que tout fonctionne ensemble:
+ +De plus, si vous utilisez 10 widgets avec un peu de CSS, yesod fabriquera un unique fichier CSS pour vous. Bien entendu si vous préférez avoir une dizaine de fichier CSS vous pouvez aussi le faire.
+C’est juste génial !
+Dans un système de routage standard (à la ruby on rails par exemple) vous avez pour chaque entrée un couple: regexp → handler
+La seule façon de découvrir la bonne règle est d’essayer de matcher l’url demandée à chaque expression régulière.
+Au lieu d’essayer chaque expression régulière, yesod regroupe et compile les routes pour les optimiser. Bien entendu pour pouvoir profiter de cet avantage au mieux, il ne faut pas que deux routes interfèrent entres elles.
+ +Cette définition de route est invalide par défaut dans yesod. Si vous voulez vraiment vous pouvez le faire foncionner quand même, mais il me semble que ça doit être quasiment toujours une mauvaise idée.
+Il vaut mieux faire :
+ +et faire le test “est-ce que date = 2003 ?” dans le «handler».
+Si vous êtes un “haskeller”, je pense que vous ne devriez pas avoir peur de la syntaxe particulière imposée par la façon standard de faire les choses avec yesod. Il faut essayer un peu plus loin que les premiers tutoriaux du livre.
+Je pense que yesod va dans la bonne direction d’un web plus sûr et plus rapide. Même si je pense que l’avenir sera que les serveurs devront être limités à faire serveur d’API (JSON ou XML ou n’importe quel autre mode de représentation d’objets).
+Yesod est juste incroyable. Dépassez les difficultés liées à l’apprentissage d’haskell et essayez le !
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ 
+update: updated for yesod 1.2
+tl;dr: A simple yesod tutorial. Yesod is a Haskell web framework. You shouldn’t need to know Haskell.
+Why Haskell?
+
+Its efficiency (see Snap Benchmark & Warp Benchmark1). Haskell is an order of magnitude faster than interpreted languages like Ruby and Python2.
+Haskell is a high level language and make it harder to shoot you in the foot than C, C++ or Java for example. One of the best property of Haskell being:
++“If your program compile it will be very close to what the programmer intended”.
+
Haskell web frameworks handle parallel tasks perfectly. For example even better than node.js3.
+
+From the pure technical point of view, Haskell seems to be the perfect web development tool. Weaknesses of Haskell certainly won’t be technical:
+/.*/I won’t say these are not important drawbacks. But, with Haskell your web application will have both properties to absorb an impressive number of parallel requests securely and to adapt to change.
+Actually there are three main Haskell web frameworks:
+ +I don’t think there is a real winner between these three framework. The choice I made for yesod is highly subjective. I just lurked a bit and tried some tutorials. I had the feeling yesod make a better job at helping newcomers. Furthermore, apparently the yesod team seems the most active. Of course I might be wrong since it is a matter of feeling.
+
+Why did I write this article? The yesod documentation and particularly the book are excellent. But I missed an intermediate tutorial. This tutorial won’t explain all details. I tried to give a step by step of how to start from a five minute tutorial to an almost production ready architecture. Furthermore explaining something to others is a great way to learn. If you are used to Haskell and Yesod, this tutorial won’t learn you much. If you are completely new to Haskell and Yesod it might hopefully helps you. Also if you find yourself too confused by the syntax, it might helps to read this article
+During this tutorial you’ll install, initialize and configure your first yesod project. Then there is a very minimal 5 minutes yesod tutorial to heat up and verify the awesomeness of yesod. Then we will clean up the 5 minutes tutorial to use some “best practices”. Finally there will be a more standard real world example; a minimal blog system.
+The recommended way to install Haskell is to download the Haskell Platform.
+Once done, you need to install yesod. Open a terminal session and do:
+ +There are few steps but it should take some time to finish.
+You are now ready to initialize your first yesod project. Open a terminal and type:
+ +Enter your name, choose yosog for the project name and enter Yosog for the name of the Foundation. Finally choose sqlite. Now, start the development cycle:
This will compile the entire project. Be patient it could take a while the first time. Once finished a server is launched and you could visit it by clicking this link:
+ +Congratulation! Yesod works!
+++Note: if something is messed up use the following command line inside the project directory.
+ +
Until the end of the tutorial, use another terminal and let this one open in a corner to see what occurs.
+++Of course this step is not mandatory for the tutorial but it is a good practice.
+
Fortunately, there is already a .gitignore file into the yosog folder. You just have to initialize your git repository:
We are almost ready to start.
+Up until here, we have a directory containing a bunch of files and a local web server listening the port 3000. If we modify a file inside this directory, yesod should try to recompile as fast as possible the site. Instead of explaining the role of every file, let’s focus only on the important files/directories for this tutorial:
+config/routesHandler/templates/config/modelsObviously:
+
+config/routes
+ |
++is where you’ll configure the map url → Code. + | +
+Handler/
+ |
++contains the files that will contain the code called when a url is accessed. + | +
+templates/
+ |
++contains html, js and css templates. + | +
+config/models
+ |
++is where you’ll configure the persistent objects (database tables). + | +
During this tutorial we’ll modify other files as well, but we won’t explore them in detail.
+Also note, shell commands are executed in the root directory of your project instead specified otherwise.
+We are now ready to start!
+To verify the quality of the security of the yesod framework, let’s make a minimal echo application.
+++Goal:
+Make a server that when accessed
+/echo/[some text]should return a web page containing “some text” inside anh1bloc.
~/Sites/yosog $ yesod add-handler
+Name of route (without trailing R): Echo
+Enter route pattern (ex: /entry/#EntryId): /echo/#String
+Enter space-separated list of methods (ex: GET POST): GETAlmost all work is done for us. The add-handler do the following:
Update the config/route file by appending:
/echo/#String EchoR GETThis line contains three elements: the url pattern, a handler name, an http method.
+Handler/Echo.hs fileHandler.Echo in the main Application.hs fileHandler.Echo in the cabal file for building the applicationNow try to go to localhost:3000/echo/foo. You should get a message explaining getEchoR is not yet implemented.
So let’s take a look at Handler/Echo.hs:
module Handler.Echo where
+
+import Import
+
+getEchoR :: String -> Handler RepHtml
+getEchoR = error "Not yet implemented: getEchoR"This should be straightforward. Now we changes it by:
+module Handler.Echo where
+
+import Import
+
+getEchoR :: String -> Handler RepHtml
+getEchoR theText = defaultLayout [whamlet|<h1>#{theText}|]Don’t worry if you find all of this a bit cryptic. In short it just declare a function named getEchoR with one argument (theText) of type String. When this function is called, it return a Handler RepHtml whatever it is. But mainly this will encapsulate our expected result inside an html text.
After saving the file, you should see yesod recompile the application. When the compilation is finished you’ll see the message: Starting devel application.
Now you can visit: http://localhost:3000/echo/Yesod%20rocks!
TADA! It works!
+
+Even this extremely minimal web application has some impressive properties. For exemple, imagine an attacker entering this url:
+ +You can click on it to test it.
+The special characters are protected for us. A malicious user could not hide some bad script inside.
+This behavior is a direct consequence of type safety. The url string is put inside a url type. Then the interesting part in the url is put inside a String type. To pass from url type to String type some transformation are made. For example, replace all “%20” by space characters. Then to show the String inside an html document, the string is put inside an html type. Some transformations occurs like replace “<” by “<”. Thanks to yesod, this tedious job is done for us.
"http://localhost:3000/echo/some%20text%3Ca%3E" :: URL
+ ↓
+ "some text<a>" :: String
+ ↓
+ "some text &lt;a&gt;" :: HtmlYesod is not only fast, it helps us to remain secure. It protects us from many common errors in other paradigms. Yes, I am looking at you PHP!
+Even this very minimal example should be enhanced. We will clean up many details:
+Data.Text instead of Stringtemplate directoryData.TextIt is a good practice to use Data.Text instead of String.
To declare it, add this import directive to Foundation.hs (just after the last one):
We have to modify config/routes and our handler accordingly. Replace #String by #Text in config/routes:
+/echo/#Text EchoR GET
+
+And do the same in Handler/Echo.hs:
module Handler.Echo where
+
+import Import
+
+getEchoR :: Text -> Handler RepHtml
+getEchoR theText = defaultLayout [whamlet|<h1>#{theText}|]Some html (more precisely hamlet) is written directly inside our handler. We should put this part inside another file. Create the new file templates/echo.hamlet containing:
and modify the handler Handler/Echo.hs:
module Handler.Echo where
+
+import Import
+
+getEchoR :: Text -> Handler RepHtml
+getEchoR theText = defaultLayout $(widgetFile "echo")At this point, our web application is nicely structured. We use Data.Text and our views are in templates. It is the time to make a slightly more complex example.
+Let’s make another minimal application. You should see a form containing a text field and a validation button. When you enter some text (for example “Jormungad”) and validate, the next page present you the content and its reverse appended to it. In our example it should return “JormungaddagnumroJ”.
+First, add a new handler:
+ ~/Sites/yosog (master) $ yesod add-handler
+Name of route (without trailing R): Mirror
+Enter route pattern (ex: /entry/#EntryId): /mirror
+Enter space-separated list of methods (ex: GET POST): GET POSTThis time the path /mirror will accept GET and POST requests. Update the corresponding new Handler file (Handler/Mirror.hs):
module Handler.Mirror where
+
+import Import
+import qualified Data.Text as T
+
+getMirrorR :: Handler RepHtml
+getMirrorR = defaultLayout $(widgetFile "mirror")
+
+postMirrorR :: Handler RepHtml
+postMirrorR = do
+ postedText <- runInputPost $ ireq textField "content"
+ defaultLayout $(widgetFile "posted")We will need to use the reverse function provided by Data.Text which explain the additional import.
The only new thing here is the line that get the POST parameter named “content”. If you want to know more detail about it and form in general you can take look at the yesod book.
+Create the two corresponding templates (templates/mirror.hamlet and templates/posted.hamlet):
<h1> Enter your text
+<form method=post action=@{MirrorR}>
+ <input type=text name=content>
+ <input type=submit><h1>You've just posted
+<p>#{postedText}#{T.reverse postedText}
+<hr>
+<p><a href=@{MirrorR}>Get backAnd that is all. This time, we won’t need to clean up. We may have used another way to generate the form but we’ll see this in the next section.
+Just try it by clicking here.
+Also you can try to enter strange values (like <script>alert('Bad');</script>). Like before, your application is quite secure.
We saw how to retrieve http parameters. It is the time to save things into a database.
+This example will be very minimal:
+GET on /blog should display the list of articles,POST on /blog should create a new article,GET on /blog/<article id> should display the content of the article.As before add some handlers
+~/Sites/yosog (master) $ yesod add-handler
+Name of route (without trailing R): Blog
+Enter route pattern (ex: /entry/#EntryId): /blog
+Enter space-separated list of methods (ex: GET POST): GET POST
+
+~/Sites/yosog (master) $ yesod add-handler
+Name of route (without trailing R): Article
+Enter route pattern (ex: /entry/#EntryId): /blog/#ArticleId
+Enter space-separated list of methods (ex: GET POST): GETThen we declare another model object. Append the following content to config/models:
Article
+ title Text
+ content Html
+ derivingAs Html is not an instance of Read, Show and Eq, we had to add the deriving line. If you forget it, there will be an error.
After the route and the model, we write the handler. Let’s write the content of Handler/Blog.hs. We start by declaring the module and by importing some block necessary to handle Html in forms.
module Handler.Blog
+ ( getBlogR
+ , postBlogR
+ , getArticleR
+ )
+where
+
+import Import
+
+-- to use Html into forms
+import Yesod.Form.Nic (YesodNic, nicHtmlField)
+instance YesodNic AppRemark: it is a best practice to add the YesodNic instance inside Foundation.hs. I put this definition here to make things easier but you should see a warning about this orphan instance. To put the include inside Foundation.hs is left as an exercice to the reader.
Hint: Do not forget to put YesodNic and nicHtmlField inside the exported objects of the module.
entryForm :: Form Article
+entryForm = renderDivs $ Article
+ <$> areq textField "Title" Nothing
+ <*> areq nicHtmlField "Content" NothingThis function defines a form for adding a new article. Don’t pay attention to all the syntax. If you are curious you can take a look at Applicative Functor. You just have to remember areq is for required form input. Its arguments being: areq type label default_value.
-- The view showing the list of articles
+getBlogR :: Handler RepHtml
+getBlogR = do
+ -- Get the list of articles inside the database.
+ articles <- runDB $ selectList [] [Desc ArticleTitle]
+ -- We'll need the two "objects": articleWidget and enctype
+ -- to construct the form (see templates/articles.hamlet).
+ (articleWidget, enctype) <- generateFormPost entryForm
+ defaultLayout $ do
+ $(widgetFile "articles")This handler should display a list of articles. We get the list from the DB and we construct the form. Just take a look at the corresponding template:
+<h1> Articles
+$if null articles
+ <p> There are no articles in the blog
+$else
+ <ul>
+ $forall Entity articleId article <- articles
+ <li>
+ <a href=@{ArticleR articleId} > #{articleTitle article}
+<hr>
+ <form method=post enctype=#{enctype}>
+ ^{articleWidget}
+ <div>
+ <input type=submit value="Post New Article">You should remark we added some logic inside the template. There is a test and a “loop”.
+Another very interesting part is the creation of the form. The articleWidget was created by yesod. We have given him the right parameters (input required or optional, labels, default values). And now we have a protected form made for us. But we have to create the submit button.
You could take a first look by clicking here. Of course, you could not post something yet.
+Get back to Handler/Blog.hs.
postBlogR :: Handler RepHtml
+postBlogR = do
+ ((res,articleWidget),enctype) <- runFormPost entryForm
+ case res of
+ FormSuccess article -> do
+ articleId <- runDB $ insert article
+ setMessage $ toHtml $ (articleTitle article) <> " created"
+ redirect $ ArticleR articleId
+ _ -> defaultLayout $ do
+ setTitle "Please correct your entry form"
+ $(widgetFile "articleAddError")This function should be used to create a new article. We handle the form response. If there is an error we display an error page. For example if we left some required value blank. If things goes right:
+runDB $ insert article)setMessage $ ...)Here is the content of the error Page:
+<form method=post enctype=#{enctype}>
+ ^{articleWidget}
+ <div>
+ <input type=submit value="Post New Article">Finally we need to display an article. For this we will modify Handler/Article.hs
getArticleR :: ArticleId -> Handler RepHtml
+getArticleR articleId = do
+ article <- runDB $ get404 articleId
+ defaultLayout $ do
+ setTitle $ toHtml $ articleTitle article
+ $(widgetFile "article")The get404 function try to do a get on the DB. If it fails it return a 404 page. The rest should be clear. Here is the content of templates/article.hamlet:
The blog system is finished. Just for fun, you can try to create an article with the following content:
+ +This is the end of this tutorial. I made it very minimal.
+If you already know Haskell and you want to go further, you should take a look at the recent i18n blog tutorial. It will be obvious I inspired my own tutorial on it. You’ll learn in a very straightforward way how easy it is to use authorizations, Time and internationalization.
+If, on the other hand you don’t know Haskell. Then you shouldn’t jump directly to web programming. Haskell is a very complex and unusual language. My advice to go as fast as possible in using Haskell for web programming is:
+Also, note that:
+As you should see, if you don’t already know Haskell, the path is long but I guaranty you it will be very rewarding!
+ps: You can download the source of this yesod blog tutorial at github.com/yogsototh/yosog.
+One can argue these benchmark contains many problems. But the benchmarks are just here to give an order of idea. Mainly Haskell is very fast.↩
Generally high level Haskell is slower than C, but low level Haskell is equivalent to C speed. It means that even if you can easily link C code with Haskell, this is not needed to reach the same speed. Furthermore writing a web service in C/C++ seems to be a very bad idea. You can take a look at a discussion on HN about this.↩
If you are curious, you can search about the Fibonacci node.js troll. Without any tweaking, Haskell handled this problem perfectly. I tested it myself using yesod instead of Snap.↩
By view I mean yesod widget’s hamlet, lucius and julius files.↩
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ 
+Few days ago there were about 20 job offer for Haskell. In only one day! How is that possible? As a real haskeller, I find this situation unbearable!
+After all, we must avoid success at all cost. And I’ll help SPJ achieve this honorable goal.
+Imagine a situation were you see people demonstrating some interest in learning Haskell.
+Quick! Prevent them from going further.
+If they come from the dynamic (uni-typed) languages like Python, Javascript…:
+++Haskell? A statically typed language??? Hmm… You mean like C and Java?
+
Such a remark should immediately shut down any interest in Haskell.
+If they want to produce application with them:
+++Haskell? Isn’t it only a language for student! I don’t think it is useful for REAL WORLD applications!
+
If they just want to learn something new:
+++Haskell? Ah yes, I remember, mostly they only have the equivalent of Java interfaces and they stopped there. They don’t even have classes!!!! Can you imagine? I don’t even speak about class inheritance.
+We’re in 2016! And they don’t even support basic Object Oriented Programming. What a joke!
+
If they love low level programming:
+++Haskell? Ah yes, I heard that lazyness make it impossible to think about code complexity and generally cause lot of space leaks.
+
And if it is not enough:
+++Haskell? Ah yes. I’m not fan of their Stop the World GC.
+
If they come from LISP and the statically typed language remark wasn’t enough. Try to mention the lack of macros in Haskell. Don’t mention template Haskell or even less Generics and all recent progress in GHC.
+Many hints there:
+stack, cabal freeze, … While Nix is great, forcing new user completely alien to all these concepts to first learn it before starting to write their first line of code can greatly reduce their enthusiasm. Bonus point if you make them believe you can only program in Haskell on NixOS.The very first thing to do is to explain how Haskell is so easy to learn. How natural it is for everybody you know. And except someone you always considered very dumb, everybody was very productive in Haskell in few hours.
+Use vocabulary alien to them as much as possible. Here is a list of terms you should use in the very first minutes of your description of Haskell:
+Each of this term will hopefully be intimidating.
+Please don’t provide an obvious first example like:
+ +Instead prefer a fully servant example:
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE TypeOperators #-}
+
+module App where
+
+import Control.Monad.Trans.Except
+import Data.Aeson
+import GHC.Generics
+import Network.Wai
+import Network.Wai.Handler.Warp
+import Servant
+import System.IO
+
+type ItemApi =
+ "item" :> Get '[JSON] [Item] :<|>
+ "item" :> Capture "itemId" Integer :> Get '[JSON] Item
+
+itemApi :: Proxy ItemApi
+itemApi = Proxy
+
+run :: IO ()
+run = do
+ let port = 3000
+ settings =
+ setPort port $
+ setBeforeMainLoop (hPutStrLn stderr ("listening on port " ++ show port)) $
+ defaultSettings
+ runSettings settings =<< mkApp
+
+mkApp :: IO Application
+mkApp = return $ serve itemApi server
+
+server :: Server ItemApi
+server =
+ getItems :<|>
+ getItemById
+
+type Handler = ExceptT ServantErr IO
+
+getItems :: Handler [Item]
+getItems = return [exampleItem]
+
+getItemById :: Integer -> Handler Item
+getItemById = \ case
+ 0 -> return exampleItem
+ _ -> throwE err404
+
+exampleItem :: Item
+exampleItem = Item 0 "example item"
+
+data Item
+ = Item {
+ itemId :: Integer,
+ itemText :: String
+ }
+ deriving (Eq, Show, Generic)
+
+instance ToJSON Item
+instance FromJSON ItemThis nice example should overflow the number of new concepts a Haskell newcomer should deal with:
+:<|>'[] instead of []Proxy$deriving ha ha! You’ll need to explain typeclasses first!getItemByIdOf course use the most of your energy explaining the language extensions first. Use a great deal of details and if possible use as much as possible references to Category Theory. You’ll get bonus points if you mention HoTT! Double bonus points if you explain that understanding all details in HoTT is essential to use Haskell on a daily basis.
+Explain that what this does is incredible but for the wrong reasons. For example don’t mention why instance ToJSON Item is great. But insist that we achieved to serve a JSON with extreme elegance and simplicity. Keep insisting on the simplicity and forgot to mention type safety which is one of the main benefit of Servant.
If you’re afraid that this example might be too close to a real world product, you can simply use some advanced lenses examples:
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE TemplateHaskell #-}
+
+import Control.Lens.TH (makePrisms)
+import GHC.Generics (Generic)
+import Lens.Family.Total
+
+data Example a b c = C1 a | C2 b | C3 c deriving (Generic)
+
+makePrisms ''Example
+
+instance (Empty a, Empty b, Empty c) => Empty (Example a b c)
+
+example :: Example String Char Int -> String
+example = _case
+ & on _C1 (\s -> s )
+ & on _C2 (\c -> replicate 3 c )
+ & on _C3 (\n -> replicate n '!')Certainly a great example to start a new language with.
+log :: Level -> String -> IO () by (<=.=$$.).If the the trends continue toward growth, then we might need to go further at the risk of breaking our own ecosystem:
+unsafePerformIO as much as possibleYes we said, at all cost!
+So with all of this I believe we should be on the right track to avoid success at all cost!
+Sorry? What?
+Oh… Apparently I made a precedence mistake!
+SPJ didn’t asked to avoid success $ at all cost but to avoid $ success at all cost1.
Sorry! My bad! Forget about all of this. Keep the good work everybody! Haskell is certainly one of the most awesome language in the world! Its community is also just great.
+I’m really happy to see it growth every year. Thanks to all contributors making it possible to still have a lot of fun after many years using Haskell!
+And the fact that in Haskell the right choice is preferred to the easiest choice, certainly helped.
+A good point to use more LISP syntax.↩
+tl;dr: Some hints on how to make great documentation for Haskell libraries.
+Tutorial module containing nothing except documentation.Tutorial module in your cabal descriptiondoctest to check your documentation is up to dateGreat documentation make a big difference. A bad documentation could simply make people not using your lib.
+My friend was learning Haskell. To start he tried a Haskell library to make a small application. The documentation was deprecated to the point he wasn’t able to make a basic example work. How do you believe he felt? What does he thought about Haskell in general?
+So here are my hint on how to make a great documentation in Haskell.
+Documentation can take many different form.
+Tutorial (or Guide.GuideTopic)Tutorial module content:{-# OPTIONS_GHC -fno-warn-unused-imports #-}
+{-|
+ Use @my-package@ if you want to ...
+-}
+module Data.Duration.Tutorial (
+
+ -- * Introduction
+ -- $introduction
+
+ -- ** Subsection
+ -- $subsection
+
+ ) where
+
+import Data.Duration
+
+{- $introduction
+
+So here how you use it:
+
+ >>> humanReadableDuration 1002012.002
+ "11 days 14 hours 20 min 12s 2ms"
+
+The function is 'humanReadableDuration' and
+the you'll be able to click on it to go
+to its definition.
+
+You can add images: <<path-to-image.png title>>
+and links: <http://haskell-lang.org haskell>.
+
+-}
+
+{- $subsection
+
+This is a chuck of documentation
+not attached to any particular Haskell
+declaration with an untested code block:
+
+> answer = 42
+
+-}To prevent obsolescence of your tutorial, use doctest.
That way when you’ll do a stack test or cabal test you’ll get errors if some example doesn’t work anymore.
doctest is a great way to provide examples in your code documentation. These example will then be used as tests. Apparently it comes from Python community.
To use doctest, this is very simple:
-- | My function description
+--
+-- >>> myFunction 3 4
+-- 7
+myFunction :: Int -> Int -> Int
+myFunction = (+)And to make it works simply verify you have a test bloc in your .cabal file looking like this:
test-suite doctest
+ type: exitcode-stdio-1.0
+ hs-source-dirs: test
+ main-is: DocTest.hs
+ build-depend: base >= 4.7 && < 5
+ , <YOUR_LIBRARY>
+ , Glob >= 0.7
+ , doctest >= 0.9.12and in test/DocTest.hs simply use
module Main where
+
+import DocTest
+import System.FilePath.Glob (glob)
+
+main = glob "src/**/*.hs" >>= docTestNow stack test or cabal test will check the validity of your documentation.
stack install haddock or cabal install haddock> haddock src/**/*.hs
+Haddock coverage:
+ 100% ( 15 / 15) in 'Data.Duration'
+ 100% ( 3 / 3) in 'Data.Duration.Tutorial'There are plenty of alternative solution. I provide the one I believe would be used by most people. So if you use github simply create an account on travis.
Add a .travis.yml file in your repo containing the content of the file here and remove the builds you don’t need. It will build your project using a lot of different GHC versions and environemnts.
If you are afraid by such its complexity you might just want to use this one:
+sudo: false
+
+addons:
+ apt:
+ packages:
+ - libgmp-dev
+
+# Caching so the next build will be fast too.
+cache:
+ directories:
+ - $HOME/.stack
+
+before_install:
+# Download and unpack the stack executable
+- mkdir -p ~/.local/bin
+- export PATH=$HOME/.local/bin:$PATH
+- travis_retry curl -L https://www.stackage.org/stack/linux-x86_64 | tar xz --wildcards --strip-components=1 -C ~/.local/bin '*/stack'
+
+script:
+ - stack setup && stack --no-terminal --skip-ghc-check testDon’t forget to activate your repo in travis.
+For some bonus points add the build status badge in your README.md file:
Congratulation! Now if you break your documentation examples, you’ll get notified.
+You could add badges to your README.md file.
Here is a list of some: shields.io
If you didn’t declared your package to stackage, please do it. It isn’t much work. Just edit a file to add your package. And you’ll could be able to add another badge:
See Stackage Badges for more informations.
+stackIf you use stack I suggest you to use the tasty-travis template. It will include the boilerplate for:
So edit your ~/.stack/config.yaml like this:
templates:
+ params:
+ author-name: Your Name
+ author-email: your@mail.com
+ copyright: 'Copyright: (c) 2016 Your Name'
+ github-username: yourusername
+ category: DevelopmentAnd then you can create a new projec with:
+stack new my-project tasty-travisEven not doing anything, if you submit your library to hackage, haddock should generate some API documentation for free.
+But to make real documentation you need to add some manual annotations.
+Functions:
+-- | My function description
+myFunction :: T1 -- ^ arg1 description
+ -> T2 -- ^ arg2 description
+myFunction arg1 arg2 = ...Data:
+data MyData a b
+ = C1 a b -- ^ doc for constructor C1
+ | C2 a b -- ^ doc for constructor C2
+
+data MyData a b
+ = C { a :: TypeA -- ^ field a description
+ , b :: TypeB -- ^ field b description
+ }Module:
+{-|
+Module : MyModule
+Description: Short description
+Copyright : (c)
+License : MIT
+
+Here is a longer description of this module.
+With some code symbol @MyType@.
+And also a block of code:
+
+@
+data MyData = C Int Int
+
+myFunction :: MyData -> Int
+@
+
+-}Documentation Structure:
+module MyModule (
+ -- * Classes
+ C(..),
+ -- * Types
+ -- ** A data type
+ T,
+ -- ** A record
+ R,
+ -- * Some functions
+ f, g
+ ) whereThat will generate headings.
+In Haskell we have great tools like hayoo! and hoogle.
And hackage and stackage provide also a lot of informations.
But generally we lack a lot of Tutorials and Guides. This post was an attempt to help people making more of them.
+But there are other good ideas to help improve the situation.
+In clojure when you create a new project using lein new my-project a directory doc is created for you. It contains a file with a link to this blog post:
If you try to search for some clojure function on a search engine there is a big chance the first result will link to:
+clojuredocs.org: try to search for reduce, update-in or index for exampleFor each symbol necessiting a documentation. You don’t only have the details and standard documentation. You’ll also get:
+clojuredocs.org is an independant website from the official Clojure website.
Most of the time, if you google the function you search you end up on clojuredocs for wich there are many contributions.
+Currently stackage is closer to these feature than hackage. Because on stackage you have access to the README and also some comments by package.
+I believe it would be more efficient to have at least a page by module and why not a page by symbol (data, functions, typeclasses…).
+For example, we could provide details about foldl for example. Also as there would be less information to display, it will make the design cleaner.
Today, if you want to help documenting, you need to make a PR to the source of some library. While if we had an equivalent to clojuredocs for Haskell, adding documentation would simply be a few clicks away:
+There are more than 23k people on /r/haskell. If only 1% of them would take 10 minutes adding a bit of documentation it will certainly change a lot of things in the percieved documentation quality.
And last but not least,
+
+Design is a vague word. A good design should care not only about how something look, but also how users will interact with it. For example by removing things to focus on the essential.
+When I stumble upon some random blog post or random specification in the Haskell community, I had too much a feeling of old fashioned design.
+If you look at node.js community lot of their web page look cleaner, easier to read and in the end, more user friendly.
+Haskell is very different from node, I wouldn’t like to replace all long and precise documentation with short human unprecise concepts. I don’t want to transform scientific papers by tweets.
+But like the scientific community has upgraded with the use of LaTeX, I believe we could find something similar that would make, very clean environment for most of us. A kind of look and feel that will be
+
+
+tlpl: Comment utiliser vim comme une IDE très efficace
+In Learn Vim Progressively I’ve show how Vim is great for editing text, and navigating in the same file (buffer). In this short article you’ll see how I use Vim as an IDE. Mainly by using some great plugins.
+There are a lot of Vim plugins. To manage them I use vim-plug.
To install it:
+mkdir -p ~/.vim/autoload
+curl -fLo ~/.vim/autoload/plug.vim \
+ https://raw.githubusercontent.com/junegunn/vim-plug/master/plug.vim☞ Note I have two parts in my .vimrc. The first part contains the list of all my plugins. The second part contains the personal preferences I setted for each plugin. I’ll separate each part by ... in the code.
+Before anything, you should protect your eyes using a readable and low contrast colorscheme.
+For this I use solarized dark. To add it, you only have to write this in your ~/.vimrc file:
call plug#begin('~/.vim/plugged')
+
+Plug 'altercation/vim-colors-solarized'
+
+call plug#end()
+
+" -- solarized personal conf
+set background=dark
+try
+ colorscheme solarized
+catch
+endtryYou should be able to see and destroy trailing whitespaces.
+
+Plug 'bronson/vim-trailing-whitespace'You can clean trailing whitespace with :FixWhitespace.
And also you should see your 80th column.
+if (exists('+colorcolumn'))
+ set colorcolumn=80
+ highlight ColorColumn ctermbg=9
+endifOne of the most important hidden skills in programming is the ability to search and find files in your projects.
+The majority of people use something like NERDTree. This is the classical left column with a tree of files of your project. I stopped to use this. And you should probably too.
I switched to unite. No left column lost. Faster to find files. Mainly it works like Spotlight on OS X.
+First install ag (the silver search). If you don’t know ack or ag your life is going to be upgraded. This is a simple but essential tool. It is mostly a grep on steroids.
" Unite
+" depend on vimproc
+" ------------- VERY IMPORTANT ------------
+" you have to go to .vim/plugin/vimproc.vim and do a ./make
+" -----------------------------------------
+Plug 'Shougo/vimproc.vim'
+Plug 'Shougo/unite.vim'
+
+...
+
+let g:unite_source_history_yank_enable = 1
+try
+ let g:unite_source_rec_async_command='ag --nocolor --nogroup -g ""'
+ call unite#filters#matcher_default#use(['matcher_fuzzy'])
+catch
+endtry
+" search a file in the filetree
+nnoremap <space><space> :split<cr> :<C-u>Unite -start-insert file_rec/async<cr>
+" reset not it is <C-l> normally
+:nnoremap <space>r <Plug>(unite_restart)Now type space twice. A list of files appears. Start to type some letters of the file you are searching for. Select it, type return and bingo the file opens in a new horizontal split.
+
+If something goes wrong just type <space>r to reset the unite cache.
Now you are able to search file by name easily and efficiently.
+Now search text in many files. For this you use ag:
Plug 'rking/ag.vim'
+...
+" --- type ° to search the word in all files in the current dir
+nmap ° :Ag <c-r>=expand("<cword>")<cr><cr>
+nnoremap <space>/ :AgDon’t forget to add a space after the :Ag.
These are two of the most powerful shortcut for working in a project. using ° which is nicely positioned on my azerty keyboard. You should use a key close to *.
So what ° is doing? It reads the string under the cursor and search for it in all files. Really useful to search where a function is used.
If you type <space>/ followed by a string, it will search for all occurrences of this string in the project files.
So with this you should already be able to navigate between files very easily.
+
+Show which line changed since your last commit.
+Plug 'airblade/vim-gitgutter'And the “defacto” git plugin:
+Plug 'tpope/vim-fugitive'You can reset your changes from the latest git commit with :Gread. You can stage your changes with :Gwrite.
+Plug 'junegunn/vim-easy-align'
+
+...
+
+" Easy align interactive
+vnoremap <silent> <Enter> :EasyAlign<cr>Just select and type Return then space. Type Return many type to change the alignments.
If you want to align the second column, Return then 2 then space.
+C-n & C-pVim has a basic auto completion system. The shortcuts are C-n and C-p while you are in insert mode. This is generally good enough in most cases. For example when I open a file not in my configured languages.
My current Haskell programming environment is great!
+Each time I save a file, I get a comment pointing to my errors or proposing me how to improve my code.
+So here we go:
+++☞ Don’t forget to install
+ghc-modwith:cabal install ghc-mod
" ---------- VERY IMPORTANT -----------
+" Don't forget to install ghc-mod with:
+" cabal install ghc-mod
+" -------------------------------------
+
+Plug 'scrooloose/syntastic' " syntax checker
+" --- Haskell
+Plug 'yogsototh/haskell-vim' " syntax indentation / highlight
+Plug 'enomsg/vim-haskellConcealPlus' " unicode for haskell operators
+Plug 'eagletmt/ghcmod-vim'
+Plug 'eagletmt/neco-ghc'
+Plug 'Twinside/vim-hoogle'
+Plug 'pbrisbin/html-template-syntax' " Yesod templates
+
+...
+
+" -------------------
+" Haskell
+" -------------------
+let mapleader="-"
+let g:mapleader="-"
+set tm=2000
+nmap <silent> <leader>ht :GhcModType<CR>
+nmap <silent> <leader>hh :GhcModTypeClear<CR>
+nmap <silent> <leader>hT :GhcModTypeInsert<CR>
+nmap <silent> <leader>hc :SyntasticCheck ghc_mod<CR>:lopen<CR>
+let g:syntastic_mode_map={'mode': 'active', 'passive_filetypes': ['haskell']}
+let g:syntastic_always_populate_loc_list = 1
+nmap <silent> <leader>hl :SyntasticCheck hlint<CR>:lopen<CR>
+
+" Auto-checking on writing
+autocmd BufWritePost *.hs,*.lhs GhcModCheckAndLintAsync
+
+" neocomplcache (advanced completion)
+autocmd BufEnter *.hs,*.lhs let g:neocomplcache_enable_at_startup = 1
+function! SetToCabalBuild()
+ if glob("*.cabal") != ''
+ set makeprg=cabal\ build
+ endif
+endfunction
+autocmd BufEnter *.hs,*.lhs :call SetToCabalBuild()
+
+" -- neco-ghc
+let $PATH=$PATH.':'.expand("~/.cabal/bin")Just enjoy!
+
+I use - for my leader because I use , a lot for its native usage.
-ht will highlight and show the type of the block under the cursor.-hT will insert the type of the current block.-hh will unhighlight the selection.
+
+My main language at work is Clojure. And my current vim environment is quite good. I lack the automatic integration to lein-kibit thought. If I have the courage I might do it myself one day. But due to the very long startup time of clojure, I doubt I’ll be able to make a useful vim plugin.
So mainly you’ll have real rainbow-parenthesis (the default values are broken for solarized).
+I used the vim paredit plugin before. But it is too restrictive. Now I use sexp which feel more coherent with the spirit of vim.
" " -- Clojure
+Plug 'kien/rainbow_parentheses.vim'
+Plug 'guns/vim-clojure-static'
+Plug 'guns/vim-sexp'
+Plug 'tpope/vim-repeat'
+Plug 'tpope/vim-fireplace'
+
+...
+
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl RainbowParenthesesActivate
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl RainbowParenthesesLoadRound
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl RainbowParenthesesLoadSquare
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl RainbowParenthesesLoadBraces
+autocmd BufEnter *.cljs,*.clj,*.cljs.hl setlocal iskeyword+=?,-,*,!,+,/,=,<,>,.,:
+" -- Rainbow parenthesis options
+let g:rbpt_colorpairs = [
+ \ ['darkyellow', 'RoyalBlue3'],
+ \ ['darkgreen', 'SeaGreen3'],
+ \ ['darkcyan', 'DarkOrchid3'],
+ \ ['Darkblue', 'firebrick3'],
+ \ ['DarkMagenta', 'RoyalBlue3'],
+ \ ['darkred', 'SeaGreen3'],
+ \ ['darkyellow', 'DarkOrchid3'],
+ \ ['darkgreen', 'firebrick3'],
+ \ ['darkcyan', 'RoyalBlue3'],
+ \ ['Darkblue', 'SeaGreen3'],
+ \ ['DarkMagenta', 'DarkOrchid3'],
+ \ ['Darkblue', 'firebrick3'],
+ \ ['darkcyan', 'SeaGreen3'],
+ \ ['darkgreen', 'RoyalBlue3'],
+ \ ['darkyellow', 'DarkOrchid3'],
+ \ ['darkred', 'firebrick3'],
+ \ ]Working with Clojure will becomre quite smoother. You can eval any part of your code, you must launch a Clojure REPL manually in another terminal thought.
+I hope it will be useful.
+Last but not least, if you want to use my vim configuration you can get it here:
+]]>
+
+tlpl: Pour installer Haskell (OS X et Linux) copiez/collez les lignes suivante dans un terminal :
+curl https://raw.githubusercontent.com/yogsototh/install-haskell/master/install-haskell.sh | sudo zshSi vous êtes sous windows, téléchargez Haskell Platform et suivez les instructions pour utiliser Haskell LTS.
+Si vous voulez savoir le pourquoi et le comment ; lisez le reste de l’article.
+La plus grande faiblesse d’Haskell n’a rien à voir avec le langage en lui-même mais avec son écosystème.
+The main problem I’ll try to address is the one known as cabal hell. The community is really active in fixing the issue. I am very confident that in less than a year this problem will be one of the past. But to work today, I provide an install method that should reduce greatly two effects of cabal hell:
+With my actual installation method, you should minimize your headache and almost never hit a dependency error. But there could exists some. If you encounter any dependency error, ask gently to the package manager to port its package to stackage.
+So to install copy/paste the following three lines in your terminal:
+curl https://raw.githubusercontent.com/yogsototh/install-haskell/master/install-haskell.sh | sudo zshYou can read the script and you will see that this is quite straightforward.
+GHC binary for you system and install it.cabal program.As the version of libraries is fixed up until you update the Haskell LTS version, you should never use cabal sandbox. That way, you will only compile each needed library once. The compiled objects/binaries will be in your ~/.cabal directory.
This script use the latest Haskell LTS. So if you use this script at different dates, the Haskell LTS might have changed.
+While it comes to cabal hell, some solutions are sandboxes and nix. Unfortunately, sandboxes didn’t worked good enough for me after some time. Furthermore, sandboxes forces you to re-compile everything by project. If you have three yesod projects for example it means a lot of time and CPU. Also, nix didn’t worked as expected on OS X. So fixing the list of package to a stable list of them seems to me the best pragmatic way to handle the problem today.
From my point of view, Haskell LTS is the best step in the right direction. The actual cabal hell problem is more a human problem than a tool problem. This is a bias in most programmer to prefer resolve social issues using tools. There is nothing wrong with hackage and cabal. But for a package manager to work in a static typing language as Haskell, packages must work all together. This is a great strength of static typed languages that they ensure that a big part of the API between packages are compatible. But this make the job of package managing far more difficult than in dynamic languages.
+People tend not to respect the rules in package numbering1. They break their API all the time. So we need a way to organize all of that. And this is precisely what Haskell LTS provide. A set of stable packages working all together. So if a developer break its API, it won’t work anymore in stackage. And whether the developer fix its package or all other packages upgrade their usage. During this time, Haskell LTS end-users will be able to develop without dependency issues.
++The image of the cat about to jump that I slightly edited can found here +
+I myself am guilty of such behavior. It was a beginner error.↩
+
+tlpl: Apprenez comment commencer un nouveau projet Haskell. Avec en exemple le créateur de projet Haskell lui-même.
+++“Good Sir Knight, will you come with me to Camelot, and join us at the Round Table?”
+
In order to work properly with Haskell you need to initialize your environment. Typically, you need to use a cabal file, create some test for your code. Both, unit test and propositional testing (random and exhaustive up to a certain depth). You need to use git and generally hosting it on github. Also, it is recommended to use cabal sandboxes. And as bonus, an auto-update tool that recompile and retest on each file save.
In this article, we will create such an environment using a zsh script. Then we will write a Haskell project which does the same work as the zsh script. You will then see how to work in such an environment.
+If you are starting to understand Haskell but consider yourself a beginner, this tutorial will show you how to make a real application using quite surprisingly a lot of features:
+☞ zsh is by its nature more suitable to file manipulation. But the Haskell code is clearly more organized while quite terse for a multi-purpose language.
+☞ holy-project is on hackage. It can be installed with cabal update && cabal install holy-project.
I recently read this excellent article: How to Start a New Haskell Project.
+While the article is very good, I lacked some minor informations1. Inspired by it, I created a simple script to initialize a new Haskell project. During the process I improved some things a bit.
+If you want to use this script, the steps are:
+cabal-install (at least 1.18)# Download the script
+git clone https://github.com/yogsototh/init-haskell-project.git
+# Copy the script in a directory of you PATH variable
+cp init-haskell-project/holy-haskell.sh ~/bin
+# Go to the directory containing all your projects
+cd my/projects/directory
+# Launch thcript
+holy-haskell.shWhat does this script do that cabal init doesn’t do?
git with the right .gitignore file.tasty to organize your tests (HUnit, QuickCheck and SmallCheck).-Wall for ghc compilation.zsh really?
+Developing the script in zsh was easy. But considering its size, it is worth to rewrite it in Haskell. Furthermore, it will be a good exercise.
In a first time, we initialize a new Haskell project with holy-haskell.sh:
+> ./holy-haskell.sh +Bridgekeeper: Stop! +Bridgekeeper: Who would cross the Bridge of Death +Bridgekeeper: must answer me these questions three, +Bridgekeeper: ere the other side he see. +You: Ask me the questions, bridgekeeper, I am not afraid. + +Bridgekeeper: What is the name of your project? +> Holy project +Bridgekeeper: What is your name? (Yann Esposito (Yogsototh)) +> +Bridgekeeper: What is your email? (Yann.Esposito@gmail.com) +> +Bridgekeeper: What is your github user name? (yogsototh) +> +Bridgekeeper: What is your project in less than ten words? +> Start your Haskell project with cabal, git and tests. +Initialize git +Initialized empty Git repository in .../holy-project/.git/ +Create files + .gitignore + holy-project.cabal + Setup.hs + LICENSE (MIT) + test/Test.hs + test/HolyProject/Swallow/Test.hs + src/HolyProject/Swallow.hs + test/HolyProject/Coconut/Test.hs + src/HolyProject/Coconut.hs + src/HolyProject.hs + src/Main.hs +Cabal sandboxing, install and test +... + many compilations lines +... +Running 1 test suites... +Test suite Tests: RUNNING... +Test suite Tests: PASS +Test suite logged to: dist/test/holy-project-0.1.0.0-Tests.log +1 of 1 test suites (1 of 1 test cases) passed. +All Tests + Swallow + swallow test: OK + coconut + coconut: OK + coconut property: OK + 148 tests completed + +All 3 tests passed + + + +Bridgekeeper: What... is the air-speed velocity of an unladen swallow? +You: What do you mean? An African or European swallow? +Bridgekeeper: Huh? I... I don't know that. +[the bridgekeeper is thrown over] +Bridgekeeper: Auuuuuuuuuuuugh +Sir Bedevere: How do you know so much about swallows? +You: Well, you have to know these things when you're a king, you know. ++
The different steps are:
+Features to note:
+~/.gitconfig file in order to provide a default name and email.So, apparently nothing too difficult to achieve.
+We should now have an initialized Haskell environment for us to work. The first thing you should do, is to go into this new directory and launch ‘./auto-update’ in some terminal. I personally use tmux on Linux or the splits in iTerm 2 on Mac OS X. Now, any modification of a source file will relaunch a compilation and a test.
+To print the introduction text in zsh:
# init colors
+autoload colors
+colors
+for COLOR in RED GREEN YELLOW BLUE MAGENTA CYAN BLACK WHITE; do
+ eval $COLOR='$fg_no_bold[${(L)COLOR}]'
+ eval BOLD_$COLOR='$fg_bold[${(L)COLOR}]'
+done
+eval RESET='$reset_color'
+# functions
+bk(){print -- "${GREEN}Bridgekeeper: $*${RESET}"}
+bkn(){print -n -- "${GREEN}Bridgekeeper: $*${RESET}"}
+you(){print -- "${YELLOW}You: $*${RESET}"}
+...
+# the introduction dialog
+bk "Stop!"
+bk "Who would cross the Bridge of Death"
+bk "must answer me these questions three,"
+bk "ere the other side he see."
+you "Ask me the questions, bridgekeeper, I am not afraid.\n"
+...
+# the final dialog
+print "\n\n"
+bk "What... is the air-speed velocity of an unladen swallow?"
+you "What do you mean? An African or European swallow?"
+bk "Huh? I... I don't know that."
+log "[the bridgekeeper is thrown over]"
+bk "Auuuuuuuuuuuugh"
+log "Sir Bedevere: How do you know so much about swallows?"
+you "Well, you have to know these things when you're a king, you know."In the first Haskell version I don’t use colors. We see we can almost copy/paste. I just added the types.
+bk :: String -> IO ()
+bk str = putStrLn $ "Bridgekeeper: " ++ str
+
+bkn :: String -> IO ()
+bkn str = pustStr $ "Bridgekeeper: " ++ str
+
+you :: String -> IO ()
+you str = putStrLn $ "You: " ++ str
+
+intro :: IO ()
+intro = do
+ bk "Stop!"
+ bk "Who would cross the Bridge of Death"
+ bk "must answer me these questions three,"
+ bk "ere the other side he see."
+ you "Ask me the questions, bridgekeeper, I am not afraid.\n"
+
+end :: IO ()
+end = do
+ putStrLn "\n\n"
+ bk "What... is the air-speed velocity of an unladen swallow?"
+ you "What do you mean? An African or European swallow?"
+ bk "Huh? I... I don't know that."
+ putStrLn "[the bridgekeeper is thrown over]"
+ bk "Auuuuuuuuuuuugh"
+ putStrLn "Sir Bedevere: How do you know so much about swallows?"
+ you "Well, you have to know these things when you're a king, you know."Now let’s just add the colors using the ansi-terminal package. So we have to add ansi-terminal as a build dependency in our cabal file.
Edit holy-project.cabal to add it.
...
+build-depends: base >=4.6 && <4.7
+ , ansi-terminal
+...Now look at the modified Haskell code:
+import System.Console.ANSI
+
+colorPutStr :: Color -> String -> IO ()
+colorPutStr color str = do
+ setSGR [ SetColor Foreground Dull color
+ , SetConsoleIntensity NormalIntensity
+ ]
+ putStr str
+ setSGR []
+
+
+bk :: String -> IO ()
+bk str = colorPutStr Green ("Bridgekeeper: " ++ str ++ "\n")
+bkn :: String -> IO ()
+bkn str = colorPutStr Green ("Bridgekeeper: " ++ str)
+you :: String -> IO ()
+you str = colorPutStr Yellow ("You: " ++ str ++ "\n")
+
+intro :: IO ()
+intro = do
+ bk "Stop!"
+ bk "Who would cross the Bridge of Death"
+ bk "must answer me these questions three,"
+ bk "ere the other side he see."
+ you "Ask me the questions, bridgekeeper, I am not afraid.\n"
+
+end :: IO ()
+end = do
+ putStrLn "\n\n"
+ bk "What... is the air-speed velocity of an unladen swallow?"
+ you "What do you mean? An African or European swallow?"
+ bk "Huh? I... I don't know that."
+ putStrLn "[the bridgekeeper is thrown over]"
+ bk "Auuuuuuuuuuuugh"
+ putStrLn "Sir Bedevere: How do you know so much about swallows?"
+ you "Well, you have to know these things when you're a king, you know."We could put this code in src/Main.hs. Declare a main function:
main :: IO ()
+main = do
+ intro
+ endMake cabal install and run cabal run (or ./.cabal-sandbox/bin/holy-project). It works!
+In order to ask questions, here is how we do it in shell script:
+ +If we want to abstract things a bit, the easiest way in shell is to use a global variable2 which will get the value of the user input like this:
+answer=""
+ask(){
+ local info="$1"
+ bk "What is your $info?"
+ print -n "> "
+ read answer
+}
+...
+ask name
+name="$answer"In Haskell we won’t need any global variable:
+import System.IO (hFlush, stdout)
+...
+ask :: String -> IO String
+ask info = do
+ bk $ "What is your " ++ info ++ "?"
+ putStr "> "
+ hFlush stdout -- Because we want to ask on the same line.
+ getLineNow our main function might look like:
+main = do
+ intro
+ _ <- ask "project name"
+ _ <- ask "name"
+ _ <- ask "email"
+ _ <- ask "github account"
+ _ <- ask "project in less than a dozen word"
+ endYou could test it with cabal install and then ./.cabal-sandbox/bin/holy-project.
We will see later how to guess the answer using the .gitconfig file and the github API.
+I don’t really like the ability to use capital letter in a package name. So in shell I transform the project name like this:
+ +In order to achieve the same result in Haskell (don’t forget to add the split package):
import Data.Char (toLower)
+import Data.List (intercalate)
+import Data.List.Split (splitOneOf)
+...
+projectNameFromString :: String -> String
+projectNameFromString str = intercalate "-" (splitOneOf " -" (map toLower str))One important thing to note is that in zsh the transformation occurs on strings but in haskell we use list as intermediate representation:
+zsh:
+"Holy grail" ==( ${project:gs/ /-/} )=> "Holy-grail"
+ ==( ${project:l} )=> "holy-grail"
+
+haskell
+"Holy grail" ==( map toLower )=> "holy grail"
+ ==( splitOneOf " -" )=> ["holy","grail"]
+ ==( intercalate "-" )=> "holy-grail"The module name is a capitalized version of the project name where we remove dashes.
+# Capitalize a string
+capitalize(){
+ local str="$(print -- "$*" | sed 's/-/ /g')"
+ print -- ${(C)str} | sed 's/ //g'
+}-- | transform a chain like "Holy project" in "HolyProject"
+capitalize :: String -> String
+capitalize str = concatMap capitalizeWord (splitOneOf " -" str)
+ where
+ capitalizeWord :: String -> String
+ capitalizeWord (x:xs) = toUpper x:map toLower xs
+ capitalizeWord _ = []The haskell version is made by hand where zsh already had a capitalize operation on string with many words. Here is the difference between the shell and haskell way (note I splitted the effect of concatMap as map and concat):
shell:
+"Holy-grail" ==( sed 's/-/ /g' )=> "Holy grail"
+ ==( ${(C)str} )=> "Holy Grail"
+ ==( sed 's/ //g' )=> "HolyGrail"
+
+haskell:
+"Holy-grail" ==( splitOneOf " -" )=> ["Holy","grail"]
+ ==( map capitalizeWord )=> ["Holy","Grail"]
+ ==( concat )=> "HolyGrail"As the preceding example, in shell we work on strings while Haskell use temporary lists representations.
+Also I want to be quite restrictive on the kind of project name we can give. This is why I added a check function.
+ioassert :: Bool -> String -> IO ()
+ioassert True _ = return ()
+ioassert False str = error str
+
+main :: IO ()
+main = do
+ intro
+ project <- ask "project name"
+ ioassert (checkProjectName project)
+ "Use only letters, numbers, spaces and dashes please"
+ let projectname = projectNameFromString project
+ modulename = capitalize projectWhich verify the project name is not empty and use only letter, numbers and dashes:
+-- | verify if project name is conform
+checkProjectName :: String -> Bool
+checkProjectName [] = False
+checkProjectName str =
+ all (\c -> isLetter c || isNumber c || c=='-' || c==' ') strMaking a project will consists in creating files and directories whose name and content depends on the answer we had until now.
+In shell, for each file to create, we used something like:
+ +In Haskell, while possible, we shouldn’t put the file content in the source code. We have a relatively easy way to include external file in a cabal package. This is what we will be using.
+Furthermore, we need a templating system to replace small part of the static file by computed values. For this task, I choose to use hastache, a Haskell implementation of Mustache templates3.
Cabal provides a way to add files which are not source files to a package. You simply have to add a Data-Files: entry in the header of the cabal file:
data-files: scaffold/LICENSE
+ , scaffold/Setup.hs
+ , scaffold/auto-update
+ , scaffold/gitignore
+ , scaffold/interact
+ , scaffold/project.cabal
+ , scaffold/src/Main.hs
+ , scaffold/src/ModuleName.hs
+ , scaffold/src/ModuleName/Coconut.hs
+ , scaffold/src/ModuleName/Swallow.hs
+ , scaffold/test/ModuleName/Coconut/Test.hs
+ , scaffold/test/ModuleName/Swallow/Test.hs
+ , scaffold/test/Test.hsNow we simply have to create our files at the specified path. Here is for example the first lines of the LICENSE file.
+The MIT License (MIT)
+
+Copyright (c) {{year}} {{author}}
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+...It will be up to our program to replace the {{year}} and {{author}} at runtime. We have to find the files. Cabal will create a module named Paths_holy_project. If we import this module we have the function genDataFileName at our disposal. Now we can read the files at runtime like this:
...
+ do
+ pkgFilePath <- getDataFileName "scaffold/LICENSE"
+ templateContent <- readFile pkgFilePath
+ ...A first remark is for portability purpose we shouldn’t use String for file path. For example on Windows / isn’t considered as a subdirectory character. To resolve this problem we will use FilePath:
import System.Directory
+import System.FilePath.Posix (takeDirectory,(</>))
+...
+createProject ... = do
+ ...
+ createDirectory projectName -- mkdir
+ setCurrentDirectory projectName -- cd
+ genFile "LICENSE" "LICENSE"
+ genFile "gitignore" ".gitignore"
+ genFile "src/Main.hs" ("src" </> "Main.hs")
+
+genFile dataFilename outputFilename = do
+ pkgfileName <- getDataFileName ("scaffold/" ++ filename)
+ template <- readFile pkgfileName
+ transformedFile <- ??? -- hastache magic here
+ createDirectoryIfMissing True (takeDirectory outputFileName)
+ writeFile outputFileName transformedFileIn order to use hastache we can either create a context manually or use generics to create a context from a record. This is the last option we will show here. So in a first time, we need to import some modules and declare a record containing all necessary informations to create our project.
+{-# LANGUAGE DeriveDataTypeable #-}
+...
+import Data.Data
+import Text.Hastache
+import Text.Hastache.Context
+import qualified Data.ByteString as BS
+import qualified Data.ByteString.Lazy.Char8 as LZdata Project = Project {
+ projectName :: String
+ , moduleName :: String
+ , author :: String
+ , mail :: String
+ , ghaccount :: String
+ , synopsis :: String
+ , year :: String
+ } deriving (Data, Typeable)Once we have declared this, we should populate our Project record with the data provided by the user. So our main function should look like:
+main :: IO ()
+main = do
+ intro
+ project <- ask "project name"
+ ioassert (checkProjectName project)
+ "Use only letters, numbers, spaces and dashes please"
+ let projectname = projectNameFromString project
+ modulename = capitalize project
+ in_author <- ask "name"
+ in_email <- ask "email"
+ in_ghaccount <- ask "github account"
+ in_synopsis <- ask "project in less than a dozen word?"
+ current_year <- getCurrentYear
+ createProject $ Project projectname modulename in_author in_email
+ in_ghaccount in_synopsis current_year
+ endFinally we could use hastache this way:
+createProject :: Project -> IO ()
+createProject p = do
+ let context = mkGenericContext p
+ createDirectory (projectName p)
+ setCurrentDirectory (projectName p)
+ genFile context "gitignore" $ ".gitignore"
+ genFile context "project.cabal" $ (projectName p) ++ ".cabal"
+ genFile context "src/Main.hs") $ "src" </> "Main.hs"
+ ...
+
+genFile :: MuContext IO -> FilePath -> FilePath -> IO ()
+genFile context filename outputFileName = do
+ pkgfileName <- getDataFileName ("scaffold/"++filename)
+ template <- BS.readFile pkgfileName
+ transformedFile <- hastacheStr defaultConfig template context
+ createDirectoryIfMissing True (takeDirectory outputFileName)
+ LZ.writeFile outputFileName transformedFileWe use external files in mustache format. We ask question to our user to fill a data structure. We use this data structure to create a context. Hastache use this context with the external files to create the project files.
+
+We need to initialize git and cabal. For this we simply call external command with the system function.
import System.Cmd
+
+...
+main = do
+ ...
+ _ <- system "git init ."
+ _ <- system "cabal sandbox init"
+ _ <- system "cabal install"
+ _ <- system "cabal test"
+ _ <- system $ "./.cabal-sandbox/bin/test-" ++ projectNameOur job is almost finished. Now, we only need to add some nice feature to make the application more enjoyable.
+
+The first one would be to add a better error message.
+import System.Random
+
+holyError :: String -> IO ()
+holyError str = do
+ r <- randomIO
+ if r
+ then
+ do
+ bk "What... is your favourite colour?"
+ you "Blue. No, yel..."
+ putStrLn "[You are thrown over the edge into the volcano]"
+ you "You: Auuuuuuuuuuuugh"
+ bk " Hee hee heh."
+ else
+ do
+ bk "What is the capital of Assyria?"
+ you "I don't know that!"
+ putStrLn "[You are thrown over the edge into the volcano]"
+ you "Auuuuuuuuuuuugh"
+ error ('\n':str)And also update where this can be called
+ioassert :: Bool -> String -> IO ()
+ioassert True _ = return ()
+ioassert False str = holyError str.gitconfigWe want to retrieve the ~/.gitconfig file content and see if it contains a name and email information. We will need to access to the HOME environment variable. Also, as we use bytestring package for hastache, let’s take advantage of this library.
import Data.Maybe (fromJust)
+import System.Environment (getEnv)
+import Control.Exception
+import System.IO.Error
+import Control.Monad (guard)
+
+safeReadGitConfig :: IO LZ.ByteString
+safeReadGitConfig = do
+ e <- tryJust (guard . isDoesNotExistError)
+ (do
+ home <- getEnv "HOME"
+ LZ.readFile $ home ++ "/.gitconfig" )
+ return $ either (const (LZ.empty)) id e
+...
+main = do
+ gitconfig <- safeReadGitConfig
+ let (name,email) = getNameAndMail gitconfig
+ project <- ask "project name" Nothing
+ ...
+ in_author <- ask "name" name
+ ...We could note I changed the ask function slightly to take a maybe parameter.
+ask :: String -> Maybe String -> IO String
+ask info hint = do
+ bk $ "What is your " ++ info ++ "?" ++ (maybe "" (\h -> " ("++h++")") hint)
+ ...Concerning the parsing of .gitconfig, it is quite minimalist.
getNameAndMail :: LZ.ByteString -> (Maybe String,Maybe String)
+getNameAndMail gitConfigContent = (getFirstValueFor splitted "name",
+ getFirstValueFor splitted "email")
+ where
+ -- make lines of words
+ splitted :: [[LZ.ByteString]]
+ splitted = map LZ.words (LZ.lines gitConfigContent)
+
+-- Get the first line which start with
+-- 'elem =' and return the third field (value)
+getFirstValueFor :: [[LZ.ByteString]] -> String -> Maybe String
+getFirstValueFor splitted key = firstJust (map (getValueForKey key) splitted)
+
+-- return the first Just value of a list of Maybe
+firstJust :: (Eq a) => [Maybe a] -> Maybe a
+firstJust l = case dropWhile (==Nothing) l of
+ [] -> Nothing
+ (j:_) -> j
+
+-- Given a line of words ("word1":"word2":rest)
+-- getValue will return rest if word1 == key
+-- 'elem =' or Nothing otherwise
+getValueForKey :: String -- key
+ -> [LZ.ByteString] -- line of words
+ -> Maybe String -- the value if found
+getValueForKey el (n:e:xs) = if (n == (LZ.pack el)) && (e == (LZ.pack "="))
+ then Just (LZ.unpack (LZ.unwords xs))
+ else Nothing
+getValueForKey _ _ = NothingWe could notice, getNameAndMail doesn’t read the full file and stop at the first occurrence of name and mail.
+The task seems relatively easy, but we’ll see there will be some complexity hidden. Make a request on https://api.github.com/search/users?q=<email>. Parse the JSON and get the login field of the first item.
So the first problem to handle is to connect an URL. For this we will use the http-conduit package.
Generally, for simple request, we should use:
+ +But, after some research, I discovered we must declare an User-Agent in the HTTP header to be accepted by the github API. So we have to change the HTTP Header, and our code became slightly more complex:
+{-# LANGUAGE OverloadedStrings #-}
+...
+simpleHTTPWithUserAgent :: String -> IO LZ.ByteString
+simpleHTTPWithUserAgent url = do
+ r <- parseUrl url
+ let request = r { requestHeaders = [ ("User-Agent","HTTP-Conduit") ] }
+ withManager $ (return.responseBody) <=< httpLbs request
+
+getGHUser :: String -> IO (Maybe String)
+getGHUser "" = return Nothing
+getGHUser email = do
+ let url = "https://api.github.com/search/users?q=" ++ email
+ body <- simpleHTTPWithUserAgent url
+ ...So now, we have a String containing a JSON representation. In javascript we would have used login=JSON.parse(body).items[0].login. How does Haskell will handle it (knowing the J in JSON is for Javascript)?
First we will need to add the lens-aeson package and use it that way:
import Control.Lens.Operators ((^?))
+import Control.Lens.Aeson
+import Data.Aeson.Encode (fromValue)
+import qualified Data.Text.Lazy as TLZ
+import qualified Data.Text.Lazy.Builder as TLB
+
+getGHUser :: String -> IO (Maybe String)
+getGHUser email = do
+ let url = "https://api.github.com/search/users?q=" ++ email
+ body <- simpleHTTPWithUserAgent url
+ let login = body ^? key "items" . nth 0 . key "login"
+ return $ fmap jsonValueToString login
+ where
+ jsonValueToString = TLZ.unpack . TLB.toLazyText . fromValueIt looks ugly, but it’s terse. In fact each function (^?), key and nth has some great mathematical properties and everything is type safe. Unfortunately I had to make my own jsonValueToString. I hope I simply missed a simpler existing function.
You can read this article on lens-aeson and prisms to know more.
+We now have all the feature provided by the original zsh script shell. But here is a good occasion to use some Haskell great feature.
We will launch the API request sooner and in parallel to minimize our wait time:
+import Control.Concurrent
+...
+main :: IO ()
+main = do
+ intro
+ gitconfig <- safeReadGitConfig
+ let (name,email) = getNameAndMail gitconfig
+ earlyhint <- newEmptyMVar
+ maybe (putMVar earlyhint Nothing) -- if no email found put Nothing
+ (\hintmail -> do -- in the other case request the github API
+ forkIO (putMVar earlyhint =<< getGHUser hintmail)
+ return ())
+ email
+ project <- ask "project name" Nothing
+ ioassert (checkProjectName project)
+ "Use only letters, numbers, spaces and dashes please"
+ let projectname = projectNameFromString project
+ modulename = capitalize project
+ in_author <- ask "name" name
+ in_email <- ask "email" email
+ ghUserHint <- if maybe "" id email /= in_email
+ then getGHUser in_email
+ else takeMVar earlyhint
+ in_ghaccount <- ask "github account" ghUserHint
+ in_synopsis <- ask "project in less than a dozen word?" Nothing
+ current_year <- getCurrentYear
+ createProject $ Project projectname modulename in_author in_email
+ in_ghaccount in_synopsis current_year
+ endWhile it might feel a bit confusing, it is in fact quite simple.
+MVar. Mainly a variable which either is empty or contains something.MVar.MVar.If you have a github account and had set correctly your .gitconfig, you might not even wait.
We have a working product. But, I don’t consider our job finished. The code is about 335 lines.
+Considering that we:
+.gitconfigThis is quite few.
+
+For short programs it is not obvious to split them into different modules. But my personal preference is to split it anyway.
+First we put all content of src/Main.hs in src/HolyProject.hs. We rename the main function by holyStarter. And our src/Main.hs should contains:
Of course you have to remember to rename the module of src/HolyProject.hs. I separated all functions in different submodules:
HolyProject.GitConfig
+getNameAndMailFromGitConfig: retrieve name an email from .gitconfig fileHolyProject.GithubAPI
+searchGHUser: retrieve github user name using github API.HolyProject.MontyPython
+bk: bridge keeper speaksyou: you speakask: Ask a question and wait for an answerHolyProject.StringUtils: String helper functions
+projectNameFromStringcapitalizecheckProjectNameThe HolyProject.hs file contains mostly the code that ask questions, show errors and copy files using hastache.
One of the benefits in modularizing the code is that our main code is clearer. Some functions are declared only in a module and are not exported. This help us hide technical details. For example, the modification of the HTTP header to use the github API.
+
+We didn’t take much advantage of the project structure yet. A first thing is to generate some documentation. Before most function I added comment starting with -- |. These comment will be used by haddock to create a documentation. First, you need to install haddock manually.
Be sure to have haddock in your PATH. You could for example add it like this:
And if you are at the root of your project you’ll get it. And now just launch:
+ +And magically, you’ll have a documentation in dist/doc/html/holy-project/index.html.
While the Haskell static typing is quite efficient to prevent entire classes of bugs, Haskell doesn’t discard the need to test to minimize the number of bugs.
+
+It is generally said to test we should use unit testing for code in IO and QuickCheck or SmallCheck for pure code.
+A unit test example on pure code is in the file test/HolyProject/Swallow/Test.hs:
module HolyProject.Swallow.Test
+ (swallowSuite)
+where
+import Test.Tasty (testGroup, TestTree)
+import Test.Tasty.HUnit
+import HolyProject.Swallow (swallow)
+
+swallowSuite :: TestTree
+swallowSuite = testGroup "Swallow"
+ [testCase "swallow test" testSwallow]
+
+-- in Swallow: swallow = (++)
+testSwallow :: Assertion
+testSwallow = "something" @=? swallow "some" "thing"Note swallow is (++). We group tests by group. Each group can contain some test suite. Here we have a test suite with only one test. The (@=?) verify the equality between its two parameters.
So now, we could safely delete the directory test/HolyProject/Swallow and the file src/HolyProject/Swallow.hs. And we are ready to make our own real world unit test. We will first test the module HolyProject.GithubAPI. Let’s create a file test/HolyProject/GithubAPI/Test.hs with the following content:
module HolyProject.GithubAPI.Test
+( githubAPISuite
+) where
+import Test.Tasty (testGroup, TestTree)
+import Test.Tasty.HUnit
+import HolyProject.GithubAPI
+
+githubAPISuite :: TestTree
+githubAPISuite = testGroup "GithubAPI"
+ [ testCase "Yann" $ ioTestEq
+ (searchGHUser "Yann.Esposito@gmail.com")
+ (Just "\"yogsototh\"")
+ , testCase "Jasper" $ ioTestEq
+ (searchGHUser "Jasper Van der Jeugt")
+ (Just "\"jaspervdj\"")
+ ]
+
+-- | Test if some IO action returns some expected value
+ioTestEq :: (Eq a, Show a) => IO a -> a -> Assertion
+ioTestEq action expected = action >>= assertEqual "" expectedYou have to modify your cabal file. More precisely, you have to add HolyProject.GithubAPI in the exposed modules of the library secion). You also have to update the test/Test.hs file to use GithubAPI instead of Swallow.
So we have our example of unit testing using IO. We search the github nickname for some people I know and we verify github continue to give the same answer as expected.
+
+When it comes to pure code, a very good method is to use QuickCheck and SmallCheck. SmallCheck will verify all cases up to some depth about some property. While QuickCheck will verify some random cases.
+As this kind of verification of property is mostly doable on pure code, we will test the StringUtils module.
So don’t forget to declare HolyProject.StringUtils in the exposed modules in the library section of your cabal file. Remove all references to the Coconut module.
Modify the test/Test.hs to remove all references about Coconut. Create a test/HolyProject/StringUtils/Test.hs file containing:
module HolyProject.StringUtils.Test
+( stringUtilsSuite
+) where
+import Test.Tasty (testGroup, TestTree)
+import Test.Tasty.SmallCheck (forAll)
+import qualified Test.Tasty.SmallCheck as SC
+import qualified Test.Tasty.QuickCheck as QC
+import Test.SmallCheck.Series (Serial)
+import HolyProject.StringUtils
+
+stringUtilsSuite :: TestTree
+stringUtilsSuite = testGroup "StringUtils"
+ [ SC.testProperty "SC projectNameFromString idempotent" $
+ idempotent projectNameFromString
+ , SC.testProperty "SC capitalize idempotent" $
+ deeperIdempotent capitalize
+ , QC.testProperty "QC projectNameFromString idempotent" $
+ idempotent capitalize
+ ]
+
+idempotent f = \s -> f s == f (f s)
+
+deeperIdempotent :: (Eq a, Show a, Serial m a) => (a -> a) -> SC.Property m
+deeperIdempotent f = forAll $ SC.changeDepth1 (+1) $ \s -> f s == f (f s)The result is here:
++All Tests + StringUtils + SC projectNameFromString idempotent: OK + 206 tests completed + SC capitalize idempotent: OK + 1237 tests completed + QC projectNameFromString idempotent: FAIL + *** Failed! Falsifiable (after 19 tests and 5 shrinks): + "a a" + Use --quickcheck-replay '18 913813783 2147483380' to reproduce. + GithubAPI + Yann: OK + Jasper: OK + +1 out of 5 tests failed ++
The test fail, but this is not an error. Our capitalize function shouldn’t be idempotent. I simply added this test to show what occurs when a test fail. If you want to look more closely to the error you could do this:
$ ./interact
+GHCi, version 7.6.2: http://www.haskell.org/ghc/ :? for help
+Loading package ghc-prim ... linking ... done.
+Loading package integer-gmp ... linking ... done.
+Loading package base ... linking ... done.
+Prelude> :l src/HolyProject/StringUtils
+[1 of 1] Compiling HolyProject.StringUtils ( src/HolyProject/StringUtils.hs, interpreted )
+Ok, modules loaded: HolyProject.StringUtils.
+*HolyProject.StringUtils> capitalize "a a"
+"AA"
+*HolyProject.StringUtils> capitalize (capitalize "a a")
+"Aa"
+*HolyProject.StringUtils>It is important to use ./interact instead of ghci. Because we need to tell ghci how to found the package installed.
Apparently, SmallCheck didn’t found any counter example. I don’t know how it generates Strings and using deeper search is really long.
+
+Congratulation!
+Now you could start programming in Haskell and publish your own cabal package.
+For example, you have to install the test libraries manually to use cabal test.↩
There is no easy way to do something like name=$(ask name). Simply because $(ask name) run in another process which doesn’t get access to the standard input↩
Having a good level of power in templates is very difficult. imho Mustache has made the best compromise.↩
tlpl: Une introduction rapide à Parsec. Un parser en Haskell.
++From String: +
+(1+3)*(1+5+9)+To data structure: +
+
+
+
+
+tlpl: Comment déterminer de la façon la plus rationnelle possible le meilleur framework work relativement à vos besoins. Cliquez ici pour aller au résultats. Cet article n’est disponible qu’en anglais.
+This is it.
+You’ve got the next big idea.
+You just need to make a very simple web application.
It sounds easy! You just need to choose a good modern web framework, when suddenly:
+
+After your brain stack overflowed, you decide to use a very simple methodology. Answer two questions:
+Which language am I familiar with?
+What is the most popular web framework for this language?
Great! This is it.
+But, you continually hear this little voice.
+++“You didn’t made a bad choice, yes. But …
+
+you hadn’t made the best either.”
This article try to determine in the most objective and rational way the best(s) web framework(s) depending on your needs. To reach this goal, I will provide a decision tool in the result section.
+I will use the following methodology:
+Methodology
+++☞ Important Note
+
+I am far from happy to the actual result. There are a lot of biases, for example in the choice of the parameters. The same can be said about the data I gathered. I am using very imprecise informations. But, as far as I know, this is the only article which use many different parameters to help you choose a web framework.This is why I made a very flexible decision tool:
+ +
Here are the important features (properties/parameters) I selected to make the choice:
+Each feature is quite important and mostly independant from each other. I tried to embrace most important topics concerning web frameworks with these four properties. I am fully concious some people might lack another important feature. Nonetheless the methodology used here can be easily replicated. If you lack an important property add it at will and use this choice method.
+Also each feature is very hard to measure with precision. This is why we will only focus on order of magnitude.
+For each property a framework could have one of the six possible values: Excellent, Very Good, Good, Medium, Bad or Very Bad
+So how to make a decision model from these informations?
+One of the most versatile method is to give a weight for each cluster value. And to select the framework maximizing this score:
+score(framework) = efficiency + robustness + expressiveness + popularity++For example:
++ +
++ +Expressiveness +10 +7 +1 +-∞ +-∞ +-∞ ++ +Popularity +5 +5 +4 +3 +2 +1 ++ +Efficiency +10 +8 +6 +4 +2 +1 ++ + +Robustness +10 +8 +6 +4 +2 +1 +Using this weighted table, that means:
++
+- we discard the three least expressive clusters.
+- We don’t make any difference between excellent and very good in popularity.
+- Concerning efficient framework in excellent cluster will have 2 more points than the “very good” cluster.
+So for each framework we compute its score relatively to a weighted table. And we select the best(s).
+Example: Using this hypothetic framework and the preceeding table.
++ +
++ + + ++ Expressiveness +Popularity +Efficiency +Robustness ++ + +yog +Excellent +Very Bad +Medium +Very Good ++score(yog) = 10 + 0 + 4 + 8 = 22
Most needs should be expressed by such a weighted table. In the result section, we will discuss this further.
+It is now time to try to get these measures.
+None of the four properties I choosen can be measured with perfect precision. But we could get the order of magnitude for each.
+I tried to focus on the framework only. But it is often easier to start by studying the language first.
+For example, I have datas about popularity by language and I also have different datas concerning popularity by framework. Even if I use only the framework focused datas in my final decision model, it seemed important to me to discuss about the datas for the languages. The goal is to provide a tool to help decision not to give a decision for you.
+RedMonk Programming Language Rankings (January 2013) provide an apparent good measure of popularity. While not perfect the current measure feel mostly right. They create an image using stack overflow and github data. Vertical correspond to the number of questions on stackoverflow. Horizontal correspond to the number of projects on github.
+If you look at the image, your eye can see about four clusters. The 1st cluster correspond to mainstream languages:
+
+Most developer know at least one of these language.
+The second cluster is quite bigger. It seems to correspond to languages with a solid community behind them.
+
+I don’t get into detail, but you could also see third and fourth tier popular languages.
+So:
+Mainstream: JavaScript, Java, PHP, Python, Ruby, C#, C++, C, Objective-C, Perl, Shell
Good: Scala, Haskell, Visual Basic, Assembly, R, Matlab, ASP, ActionScript, Coffeescript, Groovy, Clojure, Lua, Prolog
+Medium: Erlang, Go, Delphi, D, Racket, Scheme, ColdFusion, F#, FORTRAN, Arduino, Tcl, Ocaml
+Bad: third tier Very Bad: fourth tier
+I don’t thing I could find easily web frameworks for third or fourth tier languages.
+For now, I only talked about language popularity. But what about framework popularity? I made a test using number of question on stackoverflow only. Then by dividing by two for each 6 cluster:
+| Cluster | +Language | +Framework | +#nb | +% | +
|---|---|---|---|---|
| Excellent | +Ruby | +Rails | +176208 | +100% | +
| Very Good | +Python | +Django | +57385 | +<50% | +
| + | Java | +Servlet | +54139 | ++ |
| + | Java | +Spring | +31641 | ++ |
| + | Node.js | +node.js | +27243 | ++ |
| + | PHP | +Codeigniter | +21503 | ++ |
| + | Groovy | +Grails | +20222 | ++ |
| Good | +Ruby | +Sinatra | +8631 | +<25% | +
| + | Python | +Flask | +7062 | ++ |
| + | PHP | +Laravel | +6982 | ++ |
| + | PHP | +Kohana | +5959 | ++ |
| + | Node.js | +Express | +5009 | ++ |
| Medium | +PHP | +Cake | +4554 | +<13% | +
| + | C♯ | +ServiceStack | +3838 | ++ |
| + | Scala | +Play | +3823 | ++ |
| + | Java | +Wicket | +3819 | ++ |
| + | Dart | +Dart | +3753 | ++ |
| + | PHP | +Slim | +3361 | ++ |
| + | Python | +Tornado | +3321 | ++ |
| + | Scala | +Lift | +2844 | ++ |
| + | Go | +Go | +2689 | ++ |
| Bad | +Java | +Tapestry | +1197 | +<6% | +
| + | C♯ | +aspnet | +1000 | ++ |
| + | Haskell | +Yesod | +889 | ++ |
| + | PHP | +Silex | +750 | ++ |
| + | PHP | +Lithium | +732 | ++ |
| + | C♯ | +nancy | +705 | ++ |
| Very bad | +Java | +Grizzly | +622 | +<3% | +
| + | Erlang | +Cowboy | +568 | ++ |
| + | Perl | +Dancer | +496 | ++ |
| + | PHP | +Symphony2 | +491 | ++ |
| + | Go | +Revel | +459 | ++ |
| + | Clojure | +Compojure | +391 | ++ |
| + | Perl | +Mojolicious | +376 | ++ |
| + | Scala | +Scalatra | +349 | ++ |
| + | Scala | +Finagle | +336 | ++ |
| + | PHP | +Phalcon | +299 | ++ |
| + | js | +Ringo | +299 | ++ |
| + | Java | +Gemini | +276 | ++ |
| + | Haskell | +Snap | +263 | ++ |
| + | Perl | +Plack | +257 | ++ |
| + | Erlang | +Elli | +230 | ++ |
| + | Java | +Dropwizard | +188 | ++ |
| + | PHP | +Yaf | +146 | ++ |
| + | Java | +Play1 | +133 | ++ |
| + | Node.js | +Hapi | +131 | ++ |
| + | Java | +Vertx | +60 | ++ |
| + | Scala | +Unfiltered | +42 | ++ |
| + | C | +onion | +18 | ++ |
| + | Clojure | +http-kit | +17 | ++ |
| + | Perl | +Kelp | +16 | ++ |
| + | PHP | +Micromvc | +13 | ++ |
| + | Lua | +Openresty | +8 | ++ |
| + | C++ | +cpoll-cppsp | +5 | ++ |
| + | Clojure | +Luminus | +3 | ++ |
| + | PHP | +Phreeze | +1 | ++ |
As we can see, our framework popularity indicator can be quite different from its language popularity. For now I didn’t found a nice way to merge the results from RedMonk with these one. So I’ll use these unperfect one. Hopefully the order of magninute is mostly correct for most framework.
+Another objective measure is efficiency. We all know benchmarks are all flawed. But they are the only indicators concerning efficiency we have.
+I used the benchmark from benchmarksgame. Mainly, there are five clusters:
+| 1x→2x | +C, C++ |
+
| 2x→3x | +Java 7, Scala, OCamL, Haskell, Go, Common LISP | +
| 3x→10x | +C♯, Clojure, Racket, Dart | +
| 10x→30x | +Erlang | +
| 30x→ | +PHP, Python, Perl, Ruby, JRuby | +
Remarks concerning some very slow languages:
+This is a first approach. The speed of the language for basic benchmarks. But, here we are interrested in web programming. Fortunately techempower has made some tests focused on most web frameworks:
+ +These benchmark doesn’t fit well with our needs. The values are certainly quite imprecise to your real usage. The goal is just to get an order of magnitude for each framework. Another problem is the high number of informations.
+As always, we should remember these informations are also imprecise. So I simply made some classes of efficiency.
+Remark: I separated the clusters by using power of 2 relatively to the fastest.
+| Cluster | +Language | +Framework | +#nb | +slowness | +
|---|---|---|---|---|
| Excellent | +C++ | +cpoll-cppsp | +114,711 | +1× | +
| + | Jav | +gemini | +105,204 | ++ |
| + | Lua | +openresty | +93,882 | ++ |
| + | Jav | +servlet | +90,580 | ++ |
| + | C++ | +cpoll-pool | +89,167 | ++ |
| + | Go | +go | +76,024 | ++ |
| + | Sca | +finagle | +68,413 | ++ |
| + | Go | +revel | +66,990 | ++ |
| + | Jav | +rest-express | +63,209 | ++ |
| Very Good | +Jav | +wicket | +48,772 | +>2× | +
| + | Sca | +scalatra | +48,594 | ++ |
| + | Clj | +http-kit | +42,703 | ++ |
| + | Jav | +spring | +36,643 | +>3× | +
| + | PHP | +php | +36,605 | ++ |
| + | Jav | +tapestry | +35,032 | ++ |
| + | Clj | +compojure | +32,088 | ++ |
| + | JS | +ringo | +31,962 | ++ |
| + | Jav | +dropwizard | +31,514 | ++ |
| + | Clj | +luminus | +30,672 | ++ |
| Good | +Sca | +play-slick | +29,950 | +>4× | +
| + | Sca | +unfiltered | +29,782 | ++ |
| + | Erl | +elli | +28,862 | ++ |
| + | Jav | +vertx | +28,075 | ++ |
| + | JS | +nodejs | +27,598 | ++ |
| + | Erl | +cowboy | +24,669 | ++ |
| + | C | +onion | +23,649 | ++ |
| + | Hkl | +yesod | +23,304 | ++ |
| + | JS | +express | +22,856 | +>5× | +
| + | Sca | +play-scala | +22,372 | ++ |
| + | Jav g | +rizzly-jersey | +20,550 | ++ |
| + | Py | +tornado | +20,372 | +>6× | +
| + | PHP | +phalcon | +18,481 | ++ |
| + | Grv | +grails | +18,467 | ++ |
| + | Prl | +plack | +16,647 | +>7× | +
| + | PHP | +yaf | +14,388 | ++ |
| Medium | +JS | +hapi | +11,235 | +>10× | +
| + | Jav | +play1 | +9,979 | ++ |
| + | Hkl | +snap | +9,196 | ++ |
| + | Prl | +kelp | +8,250 | ++ |
| + | Py | +flask | +8,167 | ++ |
| + | Jav | +play-java | +7,905 | ++ |
| + | Jav p | +lay-java-jpa | +7,846 | ++ |
| + | PHP | +micromvc | +7,387 | ++ |
| + | Prl | +dancer | +5,040 | +>20× | +
| + | Prl | +mojolicious | +4,371 | ++ |
| + | JS | +ringo-conv | +4,249 | ++ |
| + | Py | +django | +4,026 | ++ |
| + | PHP | +codeigniter | +3,809 | +>30× | +
| Bad | +Rby | +rails | +3,445 | ++ |
| + | Sca | +lift | +3,311 | ++ |
| + | PHP | +slim | +3,112 | ++ |
| + | PHP | +kohana | +2,378 | +>40× | +
| + | PHP | +silex | +2,364 | ++ |
| Very Bad | +PHP | +laravel | +1,639 | +>60× | +
| + | PHP | +phreeze | +1,410 | ++ |
| + | PHP | +lithium | +1,410 | ++ |
| + | PHP | +fuel | +1,410 | ++ |
| + | PHP | +cake | +1,287 | +>80× | +
| + | PHP | +symfony2 | +879 | +>100× | +
| + | C# | +aspnet-mvc | +871 | ++ |
| + | Rby | +sinatra | +561 | +>200× | +
| + | C# | +servicestack | +51 | ++ |
| + | Dar | +dart | +0 | ++ |
| + | C# | +nancy | +0 | ++ |
| + | Prl | +web-simple | +0 | ++ |
These are manually made clusters. But you get the idea. Certainly, some framework could jump between two different clusters. So this is something to remember. But as always, the order of magnitude is certainly mostly right.
+Now, how to objectively measure expressiveness?
+RedMonk had a very good idea to find an objective (while imprecise) measure of each language expressiveness. Read this article for details.
+After filtering languages suitable for web development, we end up with some clusters:
+| Cluster | +Languages | +
|---|---|
| Excellent | +Coffeescript, Clojure, Haskell | +
| Very Good | +Racket, Groovy, R, Scala, OCamL, F♯, Erlang, Lisp, Go | +
| Medium | +Perl, Python, Objective-C, Scheme, Tcl, Ruby | +
| Bad | +Lua, Fortran (free-format), PHP, Java, C++, C♯ | +
| Very Bad | +Assembly, C, Javascript, | +
Unfortunately there is no information about dart. So I simply give a very fast look at the syntax. As it looked a lot like javascript and js is quite low. I decided to put it close to java.
+Also an important remark, javascript score very badly here while coffeescript (compiling to js) score “excellent”. So if you intend to use a javascript framework but only with coffescript that should change substantially the score. As I don’t believe it is the standard. Javascript oriented framework score very badly regarding expressiveness.
+| Cluster | +Language | +Framework | +
|---|---|---|
| Excellent | +Clj | +luminus | +
| + | Clj | +http-kit | +
| + | Clj | +compojure | +
| + | Hkl | +snap | +
| + | Hkl | +yesod | +
| Very Good | +Erl | +elli | +
| + | Erl | +cowboy | +
| + | Go | +go | +
| + | Go | +revel | +
| + | Grv | +grails | +
| + | Sca | +lift | +
| + | Sca | +finagle | +
| + | Sca | +scalatra | +
| + | Sca | +play-scala | +
| + | Sca | +play-slick | +
| + | Sca | +unfiltered | +
| Medium | +Prl | +kelp | +
| + | Prl | +plack | +
| + | Prl | +dancer | +
| + | Prl | +web-simple | +
| + | Prl | +mojolicious | +
| + | Py | +flask | +
| + | Py | +django | +
| + | Py | +tornado | +
| + | Rby | +rails | +
| + | Rby | +sinatra | +
| Bad | +C# | +nancy | +
| + | C# | +aspnet-mvc | +
| + | C# | +servicestack | +
| + | C++ | +cpoll-pool | +
| + | C++ | +cpoll-cppsp | +
| + | Dar | +dart | +
| + | Jav | +play1 | +
| + | Jav | +vertx | +
| + | Jav | +gemini | +
| + | Jav | +spring | +
| + | Jav | +wicket | +
| + | Jav | +servlet | +
| + | Jav | +tapestry | +
| + | Jav | +play-java | +
| + | Jav | +dropwizard | +
| + | Jav | +rest-express | +
| + | Jav | +play-java-jpa | +
| + | Jav | +grizzly-jersey | +
| + | Lua | +openresty | +
| + | PHP | +php | +
| + | PHP | +yaf | +
| + | PHP | +cake | +
| + | PHP | +fuel | +
| + | PHP | +slim | +
| + | PHP | +silex | +
| + | PHP | +kohana | +
| + | PHP | +laravel | +
| + | PHP | +lithium | +
| + | PHP | +phalcon | +
| + | PHP | +phreeze | +
| + | PHP | +micromvc | +
| + | PHP | +symfony2 | +
| + | PHP | +codeigniter | +
| Very Bad | +C | +onion | +
| + | JS | +hapi | +
| + | JS | +ringo | +
| + | JS | +nodejs | +
| + | JS | +express | +
| + | JS | +ringo-conv | +
I couldn’t find any complete study to give the number of bug relatively to each framework/language.
+But one thing I saw from experience is the more powerful the type system the safest your application is. While the type system doesn’t remove completely the need to test your application a very good type system tend to remove complete classes of bug.
+Typically, not using pointer help to reduce the number of bugs due to bad references. Also, using a garbage collector, reduce greatly the probability to access unallocated space.
+
+From my point of view, robustness is mostly identical to safety.
+Here are the clusters:
+| Excellent | +Haskell, Scheme, Erlang | +
| Very Good | +Scala, Java, Clojure | +
| Good | +Ruby, Python, Groovy, javascript, PHP | +
| Medium | +C++, C#, Perl, Objective-C, Go, C | +
So applying this to frameworks gives the following clusters:
+| Cluster | +Language | +Framework | +
|---|---|---|
| Excellent | +Erl | +elli | +
| + | Erl | +cowboy | +
| + | Hkl | +snap | +
| + | Hkl | +yesod | +
| Very Good | +Clj | +luminus | +
| + | Clj | +http-kit | +
| + | Clj | +compojure | +
| + | Jav | +play1 | +
| + | Jav | +vertx | +
| + | Jav | +gemini | +
| + | Jav | +spring | +
| + | Jav | +wicket | +
| + | Jav | +servlet | +
| + | Jav | +tapestry | +
| + | Jav | +play-java | +
| + | Jav | +dropwizard | +
| + | Jav | +rest-express | +
| + | Jav | +play-java-jpa | +
| + | Jav | +grizzly-jersey | +
| + | Sca | +lift | +
| + | Sca | +finagle | +
| + | Sca | +scalatra | +
| + | Sca | +play-scala | +
| + | Sca | +play-slick | +
| + | Sca | +unfiltered | +
| Good | +Grv | +grails | +
| + | JS | +hapi | +
| + | JS | +ringo | +
| + | JS | +nodejs | +
| + | JS | +express | +
| + | JS | +ringo-conv | +
| + | Lua | +openresty | +
| + | PHP | +php | +
| + | PHP | +yaf | +
| + | PHP | +cake | +
| + | PHP | +fuel | +
| + | PHP | +slim | +
| + | PHP | +silex | +
| + | PHP | +kohana | +
| + | PHP | +laravel | +
| + | PHP | +lithium | +
| + | PHP | +phalcon | +
| + | PHP | +phreeze | +
| + | PHP | +micromvc | +
| + | PHP | +symfony2 | +
| + | PHP | +codeigniter | +
| + | Py | +flask | +
| + | Py | +django | +
| + | Py | +tornado | +
| + | Rby | +rails | +
| + | Rby | +sinatra | +
| Medium | +C | +onion | +
| + | C# | +nancy | +
| + | C# | +aspnet-mvc | +
| + | C# | +servicestack | +
| + | C++ | +cpoll-pool | +
| + | C++ | +cpoll-cppsp | +
| + | Dar | +dart | +
| + | Go | +go | +
| + | Go | +revel | +
| + | Prl | +kelp | +
| + | Prl | +plack | +
| + | Prl | +dancer | +
| + | Prl | +web-simple | +
| + | Prl | +mojolicious | +
For the result I initialized the table with my own needs.
+And I am quite happy it confirms my current choice. I sware I didn’t given yesod any bonus point. I tried to be the most objective and factual as possible.
+Now, it is up to you to enter your preferences.
+On each line you could change how important a feature is for you. From essential to unsignificant. Of course you could change the matrix at will.
+I just show a top 10 frameworks. In order to give a more understandable measure I provide the log of the score.
+| + | ++Excellent + | ++Very good + | ++Good + | ++Medium + | ++Bad + | ++Very bad + | ++Importance + | +
|---|---|---|---|---|---|---|---|
| +Expressiveness + | +|||||||
| +Popularity + | +|||||||
| +Efficiency + | +|||||||
| +Robustness + | +
I didn’t had the courage in explaining in what the scoring system is good. Mostly, if you use product instead of sum for the score you could use power of e for the values in the matrix. And you could see the matrix as a probability matrix (each line sum to 1). Which provide a slighly better intuition on whats going on.
+Remember only that values are exponential. Do not double an already big value for example the effect would be extreme.
+All of this is based as most as I could on objective data. The choice method seems both rather rational and classical. It is now up to you to edit the score matrix to set your needs.
+I know that in the current state there are many flaws. But it is a first system to help make a choice rationally.
+I encourage you to go further if you are not satisfied by my method.
+The source code for the matrix shouldn’t be too hard to read. Just read the source of this webpage. You could change the positionning of some frameworks if you believe I made some mistake by placing them in some bad clusters.
+So I hope this tool will help you in making your life easier.
]]>
+
+tlpl: Comment j’utilise hakyll. Abréviations, corrections typographiques, multi-language, utilisation d’index.html, etc…
Ce site web est fait avec Hakyll.
+Hakyll peut être vu comme un cms minimaliste. D’une façon plus générale, il s’agit d’une bibliothèque qui facilite la création automatique de fichiers.
+D’un point de vue utilisateur voici comment j’écris mes articles :
+Un titre de page
+================
+
+Un titre de chapitre
+--------------------
+
+Azur, nos bêtes sont bondées d'un cri.
+Je m'éveille songeant au fruit noir de l'anibe dans sa cupule
+véruqueuse et tronquée.
+
+Saint John Perse.
+
+### Titre 3
+
+> C'est un blockquote.
+>
+> C'est un second paragraphe dans le blockquote
+>
+> ## C'est un H2 dans un blockquotegit push. Mon blog est hébergé sur github.A ne pas y regarder de trop près, on peut réduire le rôle d’Hakyll à :
+++Créer (resp. mettre à jour) un fichier html lorsque je crée (resp. modifie) un fichier markdown.
+
Bien que cela semble facile, il y a de nombreux détails cachés :
+Le travail d’Hakyll est de vous aider avec tout ça. Commençons par expliquer les concepts basiques.
+
+Pour chaque fichier que vous créer, il faut fournir :
+Commençons par le cas le plus simple ; les fichiers statiques (images, fontes, etc…) Généralement, vous avec un répertoire source (ici le répertoire courant) et une répertoire destination _site.
Le code Hakyll est :
+-- pour chaque fichier dans le répertoire static
+match "static/*" do
+ -- on ne change pas le nom ni le répertoire
+ route idRoute
+ -- on ne modifie pas le contenu
+ compile copyFileCompilerCe programme va copier static/foo.jpg dans _site/static/foo.jpg. C’est un peu lourd pour un simple cp. Maintenant comment faire pour transformer automatiquement un fichier markdown dans le bon html?
-- pour chaque fichier avec un extension md
+match "posts/*.md" do
+ -- changer son extension en html
+ route $ setExtension "html"
+ -- utiliser la librairie pandoc pour compiler le markdown en html
+ compile $ pandocCompilerSi vous créez un fichier posts/toto.md, cela créera un fichier _site/posts/toto.html.
Si le fichier posts/foo.md contient
le fichier _site/posts/foo.html, contiendra
Mais horreur ! _site/posts/cthulhu.html n’est pas un html complet. Il ne possède ni header, ni footer, etc… C’est ici que nous utilisons des templates. J’ajoute une nouvelle directive dans le bloc “compile”.
match "posts/*.md" do
+ route $ setExtension "html"
+ compile $ pandocCompiler
+ -- use the template with the current content
+ >>= loadAndApplyTemplate "templates/post.html" defaultContextMaintenant si templates/posts.html contient:
<html>
+ <head>
+ <title>How could I get the title?</title>
+ </head>
+ <body>
+ $body$
+ </body>
+</html>Maintenant notre ctuhlhu.html contient
<html>
+ <head>
+ <title>How could I get the title?</title>
+ </head>
+ <body>
+ <h1>Cthulhu</h1>
+ <p>ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn</p>
+ </body>
+</html>C’est facile. Mais il reste un problème à résoudre. Comment pouvons-nous changer le titre ? Ou par exemple, ajouter des mots clés ?
+La solution est d’utiliser les Contexts. Pour cela, nous devrons ajouter des metadonnées à notre markdown1.
Et modifier légèrement notre template :
+ +Super facile!
+La suite de l’article est en Anglais. Je la traduirai volontier si suffisamment de personnes me le demande gentillement.
+Now that we understand the basic functionality. How to:
+That’s easy. Simply call the executable using unixFilter. Of course you’ll have to install SASS (gem install sass). And we also use compressCss to gain some space.
match "css/*" $ do
+ route $ setExtension "css"
+ compile $ getResourceString >>=
+ withItemBody (unixFilter "sass" ["--trace"]) >>=
+ return . fmap compressCssIn order to help to reference your website on the web, it is nice to add some keywords as meta datas to your html page.
+ +In order to add keywords, we could not directly use the markdown metadatas. Because, without any, there should be any meta tag in the html.
+An easy answer is to create a Context that will contains the meta tag.
-- metaKeywordContext will return a Context containing a String
+metaKeywordContext :: Context String
+-- can be reached using $metaKeywords$ in the templates
+-- Use the current item (markdown file)
+metaKeywordContext = field "metaKeywords" $ \item -> do
+ -- tags contains the content of the "tags" metadata
+ -- inside the item (understand the source)
+ tags <- getMetadataField (itemIdentifier item) "tags"
+ -- if tags is empty return an empty string
+ -- in the other case return
+ -- <meta name="keywords" content="$tags$">
+ return $ maybe "" showMetaTags tags
+ where
+ showMetaTags t = "<meta name=\"keywords\" content=\""
+ ++ t ++ "\">\n"Then we pass this Context to the loadAndApplyTemplate function:
match "posts/*.md" do
+ route $ setExtension "html"
+ compile $ pandocCompiler
+ -- use the template with the current content
+ >>= loadAndApplyTemplate "templates/post.html"
+ (defaultContext <> metaKeywordContext)++☞ Here are the imports I use for this tutorial.
++{-# LANGUAGE OverloadedStrings #-} +import Control.Monad (forM,forM_) +import Data.List (sortBy,isInfixOf) +import Data.Monoid ((<>),mconcat) +import Data.Ord (comparing) +import Hakyll +import System.Locale (defaultTimeLocale) +import System.FilePath.Posix (takeBaseName,takeDirectory + ,(</>),splitFileName)
What I mean is to use url of the form:
+http://domain.name/post/title-of-the-post/I prefer this than having to add file with .html extension. We have to change the default Hakyll route behavior. We create another function niceRoute.
-- replace a foo/bar.md by foo/bar/index.html
+-- this way the url looks like: foo/bar in most browsers
+niceRoute :: Routes
+niceRoute = customRoute createIndexRoute
+ where
+ createIndexRoute ident =
+ takeDirectory p </> takeBaseName p </> "index.html"
+ where p=toFilePath identNot too difficult. But! There might be a problem. What if there is a foo/index.html link instead of a clean foo/ in some content?
Very simple, we simply remove all /index.html to all our links.
-- replace url of the form foo/bar/index.html by foo/bar
+removeIndexHtml :: Item String -> Compiler (Item String)
+removeIndexHtml item = return $ fmap (withUrls removeIndexStr) item
+ where
+ removeIndexStr :: String -> String
+ removeIndexStr url = case splitFileName url of
+ (dir, "index.html") | isLocal dir -> dir
+ _ -> url
+ where isLocal uri = not (isInfixOf "://" uri)And we apply this filter at the end of our compilation
+match "posts/*.md" do
+ route $ niceRoute
+ compile $ pandocCompiler
+ -- use the template with the current content
+ >>= loadAndApplyTemplate "templates/post.html" defaultContext
+ >>= removeIndexHtmlCreating an archive start to be difficult. There is an example in the default Hakyll example. Unfortunately, it assumes all posts prefix their name with a date like in 2013-03-20-My-New-Post.md.
I migrated from an older blog and didn’t want to change my url. Also I prefer not to use any filename convention. Therefore, I add the date information in the metadata published. And the solution is here:
match "archive.md" $ do
+ route $ niceRoute
+ compile $ do
+ body <- getResourceBody
+ return $ renderPandoc body
+ >>= loadAndApplyTemplate "templates/archive.html" archiveCtx
+ >>= loadAndApplyTemplate "templates/base.html" defaultContext
+ >>= removeIndexHtmlWhere templates/archive.html contains
And base.html is a standard template (simpler than post.html).
archiveCtx provide a context containing an html representation of a list of posts in the metadata named posts. It will be used in the templates/archive.html file with $posts$.
archiveCtx =
+ defaultContext <>
+ metaKeywordContext <>
+ field "posts" (\_ -> postList createdFirst)postList returns an html representation of a list of posts given an Item sort function. The representation will apply a minimal template on all posts. Then it concatenate all the results. The template is post-item.html:
Here is how it is done:
+postList :: [Item String] -> Compiler [Item String]
+ -> Compiler String
+postList sortFilter = do
+ -- sorted posts
+ posts <- loadAll "post/*" >>= sortFilter
+ itemTpl <- loadBody "templates/post-item.html"
+ -- we apply the template to all post
+ -- and we concatenate the result.
+ -- list is a string
+ list <- applyTemplateList itemTpl defaultContext posts
+ return listcreatedFirst sort a list of item and put it inside Compiler context. We need to be in the Compiler context to access metadatas.
createdFirst :: [Item String] -> Compiler [Item String]
+createdFirst items = do
+ -- itemsWithTime is a list of couple (date,item)
+ itemsWithTime <- forM items $ \item -> do
+ -- getItemUTC will look for the metadata "published" or "date"
+ -- then it will try to get the date from some standard formats
+ utc <- getItemUTC defaultTimeLocale $ itemIdentifier item
+ return (utc,item)
+ -- we return a sorted item list
+ return $ map snd $ reverse $ sortBy (comparing fst) itemsWithTimeIt wasn’t so easy. But it works pretty well.
+To create an rss feed, we have to:
+We could then render the posts twice. One for html rendering and another time for rss. Remark we need to generate the rss version to create the html one.
+One of the great feature of Hakyll is to be able to save snapshots. Here is how:
+match "posts/*.md" do
+ route $ setExtension "html"
+ compile $ pandocCompiler
+ -- save a snapshot to be used later in rss generation
+ >>= saveSnapshot "content"
+ >>= loadAndApplyTemplate "templates/post.html" defaultContextNow for each post there is a snapshot named “content” associated. The snapshots are created before applying a template and after applying pandoc. Furthermore feed don’t need a source markdown file. Then we create a new file from no one. Instead of using match, we use create:
create ["feed.xml"] $ do
+ route idRoute
+ compile $ do
+ -- load all "content" snapshots of all posts
+ loadAllSnapshots "posts/*" "content"
+ -- take the latest 10
+ >>= (fmap (take 10)) . createdFirst
+ -- renderAntom feed using some configuration
+ >>= renderAtom feedConfiguration feedCtx
+ where
+ feedCtx :: Context String
+ feedCtx = defaultContext <>
+ -- $description$ will render as the post body
+ bodyField "description"The feedConfiguration contains some general informations about the feed.
feedConfiguration :: FeedConfiguration
+feedConfiguration = FeedConfiguration
+ { feedTitle = "Great Old Ones"
+ , feedDescription = "This feed provide information about Great Old Ones"
+ , feedAuthorName = "Abdul Alhazred"
+ , feedAuthorEmail = "abdul.alhazred@great-old-ones.com"
+ , feedRoot = "http://great-old-ones.com"
+ }Great idea certainly steal from nanoc (my previous blog engine)!
+As I just said, nanoc was my preceding blog engine. It is written in Ruby and as Hakyll, it is quite awesome. And one thing Ruby does more naturally than Haskell is regular expressions. I had a lot of filters in nanoc. I lost some because I don’t use them much. But I wanted to keep some. Generally, filtering the content is just a way to apply to the body a function of type String -> String.
Also we generally want prefilters (to filter the markdown) and postfilters (to filter the html after the pandoc compilation).
+Here is how I do it:
+markdownPostBehavior = do
+ route $ niceRoute
+ compile $ do
+ body <- getResourceBody
+ prefilteredText <- return $ (fmap preFilters body)
+ return $ renderPandoc prefilteredText
+ >>= applyFilter postFilters
+ >>= saveSnapshot "content"
+ >>= loadAndApplyTemplate "templates/post.html" yContext
+ >>= loadAndApplyTemplate "templates/boilerplate.html" yContext
+ >>= relativizeUrls
+ >>= removeIndexHtmlWhere
+applyFilter strfilter str = return $ (fmap $ strfilter) str
+preFilters :: String -> String
+postFilters :: String -> StringNow we have a simple way to filter the content. Let’s augment the markdown ability.
+Comparing to LaTeX, a very annoying markdown limitation is the lack of abbreviations.
+Fortunately we can filter our content. And here is the filter I use:
+abbreviationFilter :: String -> String
+abbreviationFilter = replaceAll "%[a-zA-Z0-9_]*" newnaming
+ where
+ newnaming matched = case M.lookup (tail matched) abbreviations of
+ Nothing -> matched
+ Just v -> v
+abbreviations :: Map String String
+abbreviations = M.fromList
+ [ ("html", "<span class=\"sc\">html</span>")
+ , ("css", "<span class=\"sc\">css</span>")
+ , ("svg", "<span class=\"sc\">svg</span>")
+ , ("xml", "<span class=\"sc\">xml</span>")
+ , ("xslt", "<span class=\"sc\">xslt</span>") ]It will search for all string starting by ‘%’ and it will search in the Map if there is a corresponding abbreviation. If there is one, we replace the content. Otherwise we do nothing.
Do you really believe I type
+ +each time I write LaTeX?
+Generally I write my post in English and French. And this is more difficult than it appears. For example, I need to filter the language in order to get the right list of posts. I also use some words in the templates and I want them to be translated.
+ +First I create a Map containing all translations.
+data Trad = Trad { frTrad :: String, enTrad :: String }
+
+trads :: Map String Trad
+trads = M.fromList $ map toTrad [
+ ("changeLanguage",
+ ("English"
+ , "Français"))
+ ,("switchCss",
+ ("Changer de theme"
+ ,"Change Theme"))
+ ,("socialPrivacy",
+ ("Ces liens sociaux préservent votre vie privée"
+ ,"These social sharing links preserve your privacy"))
+ ]
+ where
+ toTrad (key,(french,english)) =
+ (key, Trad { frTrad = french , enTrad = english })Then I create a context for all key:
+tradsContext :: Context a
+tradsContext = mconcat (map addTrad (M.keys trads))
+ where
+ addTrad :: String -> Context a
+ addTrad name =
+ field name $ \item -> do
+ lang <- itemLang item
+ case M.lookup name trads of
+ Just (Trad lmap) -> case M.lookup (L lang) lmap of
+ Just tr -> return tr
+ Nothing -> return ("NO TRANSLATION FOR " ++ name)
+ Nothing -> return ("NO TRANSLATION FOR " ++ name)The full code is here. And except from the main file, I use literate Haskell. This way the code should be easier to understand.
+If you want to know why I switched from nanoc:
+My preceding nanoc website was a bit too messy. So much in fact, that the dependency system recompiled the entire website for any change.
+So I had to do something about it. I had two choices:
+I added too much functionalities in my nanoc system. Starting from scratch (almost) remove efficiently a lot of unused crap.
+So far I am very happy with the switch. A complete build is about 4x faster. I didn’t broke the dependency system this time. As soon as I modify and save the markdown source, I can reload the page in the browser.
+I removed a lot of feature thought. Some of them will be difficult to achieve with Hakyll. A typical example:
+In nanoc I could take a file like this as source:
+ +And it will create a file foo.hs which could then be downloaded.
<h1>Title</h1>
+
+<p>content</p>
+
+<a href="code/foo.hs">Download foo.hs</a>
+<pre><code>main = putStrLn "Cthulhu!"</code></pre>Nous pouvons aussi ajouter ces métadonnées dans un fichier externe (toto.md.metadata).↩
+
+tlpl: Les boutons des réseaux sociaux traquent vos utilisateurs, ont un design incohérent avec celui de votre site, utilisent des ressources, ralentissent le rendu de vos pages.
+Faite les choses bien. Utilisez des liens statiques.
+Si vous n’avez pas envie de lire, copiez et collez simplement le code suivant dans votre html :
+<div id="sociallinks">
+ <a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Tweet this</a> -
+ <a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Like this</a> -
+ <a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Share on G+</a>
+</div>
+<script>
+(function(){window.addEventListener("DOMContentLoaded",function(){
+ var url=document.location;
+ var links=document.getElementById("sociallinks")
+ .getElementsByTagName('a');
+ for (var i=0;i!=links.length;i++){
+ links[i].setAttribute("href",
+ links[i].href.replace('$url$',url));}})})();
+</script>Ever been on a website and want to tweet about it? Fortunately, the website might have a button to help you. But do you really know what this button do?
+The “Like”, “Tweet” and “+1” buttons will call a javascript. It will get access to your cookies. It helps the provider of the button to know who you are.
+In plain English, the “+1” button will inform Google you are visiting the website, even if you don’t click on “+1”. The same is true for the “like” button for facebook and the “tweet this” button for twitter.
+The problem is not only a privacy issue. In fact (sadly imho) this isn’t an issue for most people. These button consume computer ressources. Far more than a simple link. It thus slow down a bit the computer and consume energy. These button could also slow down the rendering of your web page.
+Another aspect is their design. Their look and feel is mostly imposed by the provider.
+The most problematic aspect in my opinion is to use a third party js on your website. What if tomorrow twitter update their tweet button? If the upgrade break something for only a minority of people, they won’t fix it. This could occur anytime without any notification. They just have to add a document.write in their js you call asynchronously and BAM! Your website is just an empty blank page. And as you call many external ressources, it can be very difficult to find the origin of the problem.
Using social network buttons:
+I will provide you two solutions with the following properties:
+Solution 1 (no js):
+<a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Tweet this</a>
+
+<a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Like this</a>
+
+<a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Share on G+</a>But you have to replace $url$ by the current url.
Solution 2 (Just copy/paste):
+If you don’t want to write the url yourself, you could use some minimal js:
+<div id="sociallinks">
+ <a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Tweet this</a> -
+ <a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Like this</a> -
+ <a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ >Share on G+</a>
+</div>
+<script>
+(function(){window.addEventListener("DOMContentLoaded",function(){
+ var url=document.location;
+ var links=document.getElementById("sociallinks")
+ .getElementsByTagName('a');
+ for (var i=0;i!=links.length;i++){
+ links[i].setAttribute("href",
+ links[i].href.replace('$url$',url));}})})();
+</script>Here is the result:
+If you don’t want just text but nice icons. You have many choices:
+<img src="..."/> in the links.As the first solution is pretty straightforward, I’ll explain the second one.
+@font-face
+ font-family: 'social'
+ src: url('fonts/social_font.ttf') format('truetype')
+ font-weight: normal
+ font-style: normal
+.social
+ font-family: socialNow add this to your html:
+Solution 1 (without js):
+<a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">t</a>
+·
+<a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">`</a>
+·
+<a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">g</a>Solution 2 (same with a bit more js):
+<div id="sociallinksunicode">
+<a href="https://twitter.com/home?status=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">t</a>
+·
+<a href="http://www.facebook.com/sharer/sharer.php?u=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">`</a>
+·
+<a href="https://plus.google.com/share?url=$url$"
+ target="_blank" rel="noopener noreferrer nofollow"
+ class="social">g</a>
+</div>
+<script>
+(function(){window.addEventListener("DOMContentLoaded",function(){
+ var url=document.location;
+ var links=document.getElementById("sociallinksunicode")
+ .getElementsByTagName('a');
+ for (var i=0;i!=links.length;i++){
+ links[i].setAttribute("href",
+ links[i].href.replace('$url$',url));}})})();
+</script>Here is the result:
+ps: On my personal website I continue to use Google analytics. Therefore, Google (and only Google, not facebook nor twitter) can track you here. But I might change this in the future.
]]>Yesterday I was happy to make a presentation about Category Theory at Riviera Scala Clojure Meetup (note I used only Haskell for my examples).
+ +If you don't want to read them through an HTML presentations framework or downloading a big PDF +just continue to read as a standard web page. +
+ + + + + +
+Recent Math Field
1942-45, Samuel Eilenberg & Saunders Mac Lane
Certainly one of the more abstract branches of math
+
+★: When is one thing equal to some other thing?, Barry Mazur, 2007
☆: Physics, Topology, Logic and Computation: A Rosetta Stone, John C. Baez, Mike Stay, 2009
+
+Programming is doing Math
+Strong relations between type theory and category theory.
+Not convinced?
Certainly a vocabulary problem.
One of the goal of Category Theory is to create a homogeneous vocabulary between different disciplines.
+
+Math vocabulary used in this presentation:
+++Category, Morphism, Associativity, Preorder, Functor, Endofunctor, Categorial property, Commutative diagram, Isomorph, Initial, Dual, Monoid, Natural transformation, Monad, Klesli arrows, κατα-morphism, ...
+
+| +Mathematician + | +Programmer + |
|---|---|
| +Morphism + | +Arrow + |
| +Monoid + | +String-like + |
| +Preorder + | +Acyclic graph + |
| +Isomorph + | +The same + |
| +Natural transformation + | +rearrangement function + |
| +Funny Category + | +LOLCat + |
+
+\(\ob{\mathcal{C}}\) is a collection
+
+
+\(A\) and \(B\) objects of \(\C\)
+\(\hom{A,B}\) is a collection of morphisms
+\(f:A→B\) denote the fact \(f\) belongs to \(\hom{A,B}\)
\(\hom{\C}\) the collection of all morphisms of \(\C\)
+Composition (∘): associate to each couple \(f:A→B, g:B→C\) + $$g∘f:A\rightarrow C$$ +
+
+for each object \(X\), there is an \(\id_X:X→X\),
+such that for each \(f:A→B\):
+Composition is associative:
+
+Two path with the same source and destination are equal.
+
+
+
+\(\ob{\C},\hom{\C}\) fixed, is there a valid ∘?
+
+
+
+
+
+
+
+(.) )
+(++) "" ++ u = u = u ++ "" (u ++ v) ++ w = u ++ (v ++ w)
+
+
+Each Monoid \((M,e,⊙): \ob{M}=\{∙\},\hom{M}=M,\circ = ⊙\)
+Only one object.
+Examples:
+(Integer,0,+), (Integer,1,*),
+(Strings,"",++), for each a, ([a],[],++)
+At most one morphism between two objects.
+ +
+
+Any set \(E: \ob{E}=E, \hom{x,y}=\{x\} ⇔ x=y \)
+Only identities
+ isomorphism: \(f:A→B\) which can be "undone" i.e.
\(∃g:B→A\), \(g∘f=id_A\) & \(f∘g=id_B\)
in this case, \(A\) & \(B\) are isomorphic.
A≌B means A and B are essentially the same.
In Category Theory, = is in fact mostly ≌.
For example in commutative diagrams.
+
+
+An endofunctor for \(\C\) is a functor \(F:\C→\C\).
+
+
+
+Categories and functors form a category: \(\Cat\)
+Category \(\Hask\):
+ +
+
+(.) Haskell function composition
+Forget glitches because of undefined.
Put normal function inside a container. Ex: list, trees...
+
+
+
Haskell functor can be seen as boxes containing all Haskell types and functions. +Haskell types look like a fractal:
+ +
+Haskell functor can be seen as boxes containing all Haskell types and functions. +Haskell types look like a fractal:
+ +
+Haskell functor can be seen as boxes containing all Haskell types and functions. +Haskell types look like a fractal:
+ +
+
+Let \(F\) and \(G\) be two functors from \(\C\) to \(\D\).
+ A natural transformation: familly η ; \(η_X\in\hom{\D}\) for \(X\in\ob{\C}\) s.t.
ex: between Haskell functors; F a -> G a
Rearragement functions only.
data List a = Nil | Cons a (List a)
+toList :: [a] -> List a
+toList [] = Nil
+toList (x:xs) = Cons x (toList xs)toList is a natural transformation. It is also a morphism from [] to List in the Category of \(\Hask\) endofunctors.
+
+data List a = Nil | Cons a (List a)
+toHList :: List a -> [a]
+toHList Nil = []
+toHList (Cons x xs) = x:toHList xstoHList is a natural transformation. It is also a morphism from List to [] in the Category of \(\Hask\) endofunctors.
+ toList . toHList = id & toHList . toList = id [] & List are isomorph. toMaybe :: [a] -> Maybe a
+toMaybe [] = Nothing
+toMaybe (x:xs) = Just xtoMaybe is a natural transformation. It is also a morphism from [] to Maybe in the Category of \(\Hask\) endofunctors.
+
+mToList :: Maybe a -> [a]
+mToList Nothing = []
+mToList Just x = [x]toMaybe is a natural transformation. It is also a morphism from [] to Maybe in the Category of \(\Hask\) endofunctors.
+ Bool lists longer than 1. fold
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+tlpl: Mon avis succinct et hautement subjectif concernant les différents languages de programmation que j’ai utilisé.
+BASIC
+Ah ! Le language de mes premiers programmes ! Je devais avoir 10-11 ans. Sous MO5, Amstrad CPC 6128 et même Atari STe. Le langage des GOTOs. Je suis empleint de nostalgie rien que d’y penser. C’est à peu prêt le seul intérêt de ce langage.
Aujourd’hui ce langage est tombé en désuétude. Ce n’est ni un bon langage pour apprendre, ni un bon langage pour faire de vrai programmes. Même si quelques années plus tard, je me remettais à programmer dans un basic avec un compilateur qui pourrait lui redonner vie. Je m’en était servi pour faire un livre dont vous êtes le héro :-).
+ +Je m’en souviens aussi pour avoir copier des codes de jeux vidéo à partir de magasines. La plupart des lignes ressemblaient à
+ +Quel plaisir c’était !
+
+Toujours lors que j’avais 10 ans, on pouvait faire de petits programmes sympathiques.
+Je me souviens que lors du chargement de l’application logo on avait droit à de la musique de Bach.
+Oui, il fallait charger le programme en mémoire avec une cassette. Et elle ne faisait pas les ‘Krrrkrr csssss krrrr’.
+Je l’avais utilisé sans les boucles. Des années plus tard, je le réutiliser pour faire de l’initiation à l’informatique à mes étudiants de DEUG MIAS première année. Il s’est en fait révélé très utile. Grace à lui, faire des fractales se révèle être un jeu d’enfant, au sens litéral. Je ne peux que conseiller ce langage pour apprendre à programmer et aussi pour le fun.
+Voici un exemple de code et le résultat est la jolie fractale ‘dragon’.
+HIDETURTLE
+
+PENUP
+SETXY -200 0
+RIGHT 90
+PENDOWN
+
+to dragon :degree :size
+ setpensize 1
+ if :size>5 [setpensize 2]
+ if :size>10 [setpensize 3]
+ if :size>20 [setpensize 4]
+ if :size>40 [setpensize 5]
+ ifelse :degree=0 [
+ fd :size
+ ][
+ left 45 dragon (:degree-1) (size/4)
+ right 90 dragon (:degree-1) (size/2)
+ left 90 dragon (:degree-1) (size/4)
+ right 45
+ ]
+end
+
+dragon 6 3000L’éternel numéro 2.
+J’ai dû apprendre à programmer en Pascal aux alentour de 15 ans et je l’ai aussi réutiliser un peit peu en faculté. Je dois avouer, que je le trouve inférieur au C en tous points. J’ai fait pas mal de chose avec ça, comme des algorithmes de graphes, des algorithmes de tri, et même un peu d’intelligence artificielle comme des algorithmes génétiques. Mais je préfère largement le C.
+
+Le langage des pointeurs
+Ah, le langage de programmation par excellence.
+Une fois que vous avez compris les boucles et la récursivité. Il est temps de passer aux choses sérieuses. Si vous voulez avoir du code de bonne qualité, alors apprendre le C est quasi-obligatoire.
+Ce langage est très proche du langage machine. En particulier, (la majorité du temps). Il y a une relation linéaire entre la taille du code en C et de son résultat compilé en assembleur.
+Ça signifie qu’à chaque fois que vous écrivez une ligne de C, il ne va pas se passer de choses toutes bizarres comme lancer un algorithme qui va prendre deux plombes.
+Il est très proche de la machine tout en ayant une abstraction suffisante pour ne pas être “trop” désagréable.
+J’ai fait beaucoup de choses avec. Tous les algorithmes de tri, des algorithmes d’intelligence artificielle (résolution de SAT3), du système, du réseau etc… Bref il est versatile, et on ne peut pas dire que l’on sait programmer si on ne s’est jamais mis à programmer sérieusement en C.
Le langage “super propre”.
+J’avais bien aimé ADA, mais j’avoue que ça n’a duré que le temps d’un semestre de cours. Peut-être qu’un jour je m’y remettrai. Disons qu’il est assez vieux et qu’il a inspiré la plupart des concepts objets.
+Bon, oui, le Pascal, le C, le Basic (fortran, Cobol et autres) étaient tous des langages impératifs, sans notion d’objets.
+En gros, il n’y avait pas d’aide pour structurer votre code.
+Alors, pour aider à limiter le nombre de bug, en particulier pour la création de très gros programmes, on s’est mis à réfléchir à la meilleure façon d’organiser du code d’ordinateur. À la fin, ça à donné la programmation orienté objet. Et donc les langages comme le C manquaient de système pour aider au développement orienté objet. Attention, la programmaiton orienté objet n’est pas la panacée. Combien de programme utilisez-vous qui n’ont pas de bug ? Et ça ne convient pas à tous les type de problème. Mais pour faire une application banquaire, un système de gestion des stocks, des clients ou des archives. C’est-à-dire un système d’information, c’est pas trop mal.
+Donc les langages orientés objets se sont mis à fleurir.
+
+Le malpropre
+en:
+Et oui l’industrie voulait un langage objet, mais elle n’était pas prête à mettre à la poubelle tout ses codes en C. La solution, prendre C et lui rajouter une couche objet. Le problème avec C++ c’est qu’il fait trop de choses. L’héritage multiple, des templates, etc… Bon, je l’ai quand même choisi pour faire le plus gros programme que j’ai jamais fais lors de ma thèse. Et je dois avouer que l’expérience m’a plu. Le seul reproche que j’ai à faire, c’est que la STL n’était pas aussi complète que l’on aurait pu l’espérer pour un détail. On ne peut pas faire de String<T> pour autre chose que des char16. Du coup, mon alphabet était limité à 216 lettres. Hors, pour certaines application, l’alphabet doit être gigantesque. fr: En conclusion je dirai que C++ est un très bon langage si vous vous fixez à l’avance un sous ensemble de ses fonctionnalités.
+Eiffel est un très beau langage objet. Bien plus propre que C++. Mais, à moins que les choses aient changées, il n’est pas très populaire. Derrière lui il n’a pas la communauté de C++. Pour être franc, j’ai préféré travailler en C++. J’ai menti à mes profs de l’époque pour leur faire plaisir. Lorsqu’on viens du C, il est désagréable de changer ses habitudes.
+
+On continue vers les langages objets. Alors, à une époque où j’en ai entendu parler, c’était le Graal !
+La portabilité, votre programme marchera partout. Il était orienté objet. Incrusté à l’intérieur il y avait des concepts d’architecture qui empêchent de faire n’importe quoi… Sauf que.
+Sauf qu’il est incroyablement verbeux. Et que les limitations sont très désagréables si on sait ce que l’on fait.
+Par exemple, il n’y a pas d’héritage multiple en Java. Ce qui est en général un choix que je trouve cohérent s’il est bien appuyé par des systèmes qui compensent ce manque. En java, il existe les interfaces. Les interfaces permettent d’ajouter des méthodes à une classe. En aucun cas on ne peut rajouter un attribut autrement qu’en héritant. Cet état de fait m’a vraiment géné.
+Typiquement je faisais une GUI en Java Swing. J’avais créé mon propre système de notification entre objets. Au début je considérais qu’un objet ne devait envoyer des notifications qu’à un seul objet. Ô quelle erreur lorsque je réalisais qu’il fallait non plus gérer un seul objet mais parfois plusieurs. Je changeais mon implémentation d’interface partout, conséquence, des copier/coller dans tous les sens pour mes classes. Les copier/coller qui sont justement un problème censé être évité par les langages orientés objets.
+De plus toujours pour ma GUI, je devais évidemment gérer des threads. Hors, il m’a fallu faire mon propre système de gestion de threads pour éviter les locks, pour les notifications (ce thread à fini, etc…). À l’époque j’utilisais Java 1.5. Normallement ce problème devait être réglé sur Java 1.6. J’espère que c’est le cas, mais avoir ce type de “feature” essentielle oubliée par le langage était assez grave.
+De même, il a fallu attendre très longtemps avant d’avoir des boucles foreach qui rendent le code bien plus lisible.
+Bon, après cette expérience je déconseillerai Java. La portabilité, n’est pas si intéressante que ce qu’on pourrait croire.
+En ce qui concerne les GUI, portable signifie interface fonctionnelle mais médiocre sur toutes les plateformes. Quelque soit le système d’ailleurs (wxWidget, QT, etc…). Donc, pour des applications à distribuer à des tiers, c’est à éviter.
+Le système de Java est très clos. Par contre il résout un très bon problème. Il permet à des développeurs médiocres de travailler en groupe sans faire trop de mal. Et un bon programmeur sera tout de même capable d’y faire des choses très intéressantes. Veuillez noter que je n’ai pas dit que les programmeurs Java sont de mauvais programmeurs, ce n’est pas ce que je pense.
+
+Le langage que je n’ai appris et utilisé que pour faire des applications sur les plateformes d’Apple(c). J’ai appris Objective-C après Python. Et je dois avouer que j’ai eu du mal à m’y mettre. Je n’ai pas du tout aimé la syntaxe et pas mal d’autres détails. Mais ça fait parti de ces langages que plus on utilise, plus on aime. En réalité, il y a quelque chose dans ce langage qui fait que tout est bien pensé. Mais surtout, ici, ce n’est pas le langage qui est la meilleure partie, c’est plutôt le framework Cocoa qui lui est le plus souvent associé qui est une merveille. Par rapport à tous les autres framework permettant de fabriquer des GUI, Cocoa est de très loin supérieur. Même si ça semble être des détails sur le papier, en pratique cela fait une grande différence.
+Vraiment jusqu’ici, même si Objective-C reste assez bas niveau, le fait que le typage de ce langage soit dynamique est un vrai plus pour l’interface graphique. Je ne peux que vous encourager à vous accrocher à ce langage et de faire un vrai programme avec. Vous en serez certainement plus ravi qu’il n’y parrait eu début.
+
+Le petit langage de script que nous utilisions tous pour faire des sites web à l’époque des gifs animées !
+Sympatique, mais sans plus. Apparemment il y a eu pas mal de progrès depuis PHP5, un jour peut-être que j’y reviendrai. Mais, il a derrière lui une réputation de langage pour les “scripts kiddies”. En gros ceux qui ne savent pas coder. Des trous de sécurité de tous les cotés, etc…
+En réalité, PHP est au niveau d’abstration à peine supérieur au C. Et donc, il est beaucoup moins bien organisé que des langages objets, favorisant ainsi la création de bug. Pour les applications web, c’est un vrai problème.
+PHP, reste pour moi le langage de l’injection SQL. J’en fait encore un peu de temps en temps. Et j’ai moi-même dû protéger les accès au SQL pour éviter les injections. Oui, je n’ai pas trouvé de librairie toute prête pour protéger les entrées SQL. Je n’ai pas beaucoup cherché non plus.
+
+Alors là, attention ! Révélation !
+Lorsqu’on avait l’habitude de travailler avec des langages compilé, type C++, Java et qu’on passe à Python, on se prend une claque magistrale. La programmation comme elle doit être faite. Tout est si naturel, c’est magique. Oui, c’est si bien que ça. Mais quelque chose d’aussi incroyablement bien doit avoir des inconvénients me dirais-vous.
+Et bien, oui, comme tous les langages de scripts de haut niveau, Python est lent. Attention pas juste un peu lent, comme 2 fois plus lent que du C. Non, de l’ordre de 10 à 20 fois plus lent que le C. Argh… Bon ça reste utilisable pour beaucoup de choses. Mais certaines application lui sont donc interdites.
+Des filtres de fichiers à faire. Si ce n’est pas trop compliqué, c’est le langage idéal. Vous avez un fichier et vous voulez savoir quels sont les mots les plus utilisés. Savoir combien de fois un mot est utilisé. Filtrer sous des condition un peu plus compliquées qu’un grep. Super outils. Je l’ai utilisé pour modifier en masse des centaines de fichier XML plus facilement qu’avec du XSLT.
+Perl c’est assez magique, mais la syntaxe est tellement désagréable à lire que personne ne peut vraiment aimer programmer dans un environnement de plusieurs personnes en Perl. A moins que tous les autres soient des cadors du Perl. Mais la feature qui tue, les expressions régulières :
+ +Va remplacer toto par titi dans la valeur de la variable $var. Et oui, les expressions régulière y sont intégrées directement comme avec sed et awk. Et ça rend le code beacoup plus compact (et parfois illisible). Mais c’est vraiment pas mal. C’est une sorte de awk sous stéroides.
C’est une sorte de Perl en plus propre. Un mélange de Perl et de Python. Les notion objets y sont plus fortes qu’en Python. Je l’ai beaucoup utilisé, je reste quand même un Pythoniste de préférence. Mais Ruby est vraiment très bien. Par contre en terme d’efficacité, c’est le pire langage utilisé par beaucoup de monde de ce point de vue. C’est le langage qui perd quasiment tous les benchmarks. Par contre c’est un outil parfait pour faire des prototypes. Et si vous voulez faire un prototype de site web, RoR est ce qui se fait de mieux. De l’idée au site, il ne se passera que peu de temps.
+C’est la bonne surprise. Pendant des années, javascript était considéré comme un langage tout bon à vous embéter dans votre navigation web. En réalité, javascript possède beaucoup de qualité des langages de haut niveau. En particulier, il est facille de passer une fonction en paramèter ou de créer des fonctions anonymes (closures). Récemment, il est devenu très rapide et beaucoup de frameworks et de librairies naissent un peu partout.
+En particulier avec jQuery, on peut faire des appels chainés, très agréables à utiliser. Comme je le disais, c’est une bonne surprise, javascript a été choisi un peu au hasard lors de la création des navigateurs web comme langage de script. Et il s’avère qu’à part sa syntaxe, tout le reste est bien. Heureusement, en ce qui concerne la syntaxe, on peu pallier à ce problème en utilisant CoffeeScript.
+J’ai appris CamL à la fac, j’avais trouvé cette expérience très interressante. J’étais plutôt bon, et j’avais les bonnes intuitions mathématiques qui vont avec la programmation fonctionnelle. Mais je dois avouer que je ne l’ai plus jamais utilisé. Simplement, ce type de langage semble si loin de ce qui se fait pour fabriquer des produits que ça me donnais vraiment l’impression d’être un langage pour chercheurs.
+Je suis en train d’apprendre ce langage. Et je dois dire que c’est un vrai plaisir. En général les concepts derrière tous les langages de programmation sont assez limités. Chaque langage y va de son petit lot de nouveau concepts, et en général en une après-midi, c’est appris. Pour haskell, c’est très différent. Je sens bien qu’il va me falloir plusieurs semaines pour maîtriser la bête. Ça doit faire quatre semaines que j’apprend haskell un peut tous les jours et je sais qu’il y a des notions que j’ai juste survollées et qui sont assez incroyables. Les Monades par exemple, est un concept que je n’avais jamais rencontré ailleurs. C’est un super concept. De plus le design du langage en fait un parfait système pour paralléliser les calculs naturellement. haskell sépare la partie “pure” de la partie “impure” de la programmation. À ma connaissance, c’est le seul langage de programmation qui fait ça. Enfin, je prend beaucoup de plaisir à apprendre ce langage. La communauté est aussi très acceuillante. Pas de “L0L! URAN00B!”. Et aussi pas de concession du langage pour devenir populaire. Le langage est bon, voilà tout. Alors qu’en Java et C++, typiquement certain choix ont été fait en dépis du bon sens pour “faire plaisir”.
+Metapost est un langage qui permet de programmer des dessins. Le gros plus de metapost, c’est sa capacité de résoudre automatiquement les systèmes d’équations linéaires. Par exemple, si vous écrivez :
+ +Il va position le point AA entre A et B. Plus précisément, au barycentre (2A + B)/3.
Ce deuxième exemple positionne X à l’intersection des deux segments AB et CD. Vous pouvez aussi voir pas mal d’exemples ici. You could see more example there.
Cette fonction est très utile. Et à mon avis pas seulement pour afficher des choses. De mon point de vue, les autres langages de programmation devraient penser à rajouter les résolutions automatiques simples.
+Oui, zsh est un shell. Mais c’est aussi un langage de script très bien adapté aux traitement de fichiers. Je le recommande chaudement. C’est pour l’instant le meilleur shell que j’ai utilisé. Je le préfère au bash.
+Je n’ai jamais rien fait de conséquent avec Prolog, mais j’ai adoré l’apprendre et l’utiliser. J’ai eu la chance d’apprendre Prolog par Alain Colmerauer lui-même. C’est un langage qui essaye de résoudre les contraintes autant qu’il le peut pour vous. Il en ressort un impression de magie. On ne fait que décrire ce qu’il faut et on ne donne pas d’ordre. Un peu comme la programmation fonctionnelle mais en beaucoup plus puissant.
+Il reste encore pas mal de langages et de framework à essayer. Actuellement je pense que je vais passer un moment avec Haskell. Peut-être demain que j’irai apprendre LISP, Scala ou Erlang. Comme je suis plus dans la création de site web, j’irai certainement jeter un coup d’œil à clojure aussi. Et certainement beaucoup d’autres choses.
+Dites moi si vous avez une autre expérience avec ces langages de programmation. Évidement mes impression sont hautement subjectives. Cependant, j’ai utilisé tous les langages dont j’ai parlé.
+[STL]: Standard Tempate Library [GUI]: Graphic User Interface
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Lorsque vous cliquez sur ce logo :
+
On vous propose de vous abonner au flux RSS. Mais de quoi s’agit il ?
+Si vous n’êtes pas anglophobe je vous recommande la lecture de what is rss ou encore mieux, de regarder cette vidéo RSS explained.
+Il s’agit d’un moyen facile d’agréger dans un seul endroit toutes les mises à jours de tous les sites qui vous intéressent.
+Tout d’abord, il faut choisir un client de flux RSS. Aujourd’hui il existe de nombreux client en ligne. C’est-à-dire des sites web qui vont s’occuper du regroupement. Ces client s’appellent des “aggregator”.
+Personnellement j’utilise Netvibes. J’en ai essayé vraiment beaucoup, et il reste de loin mon préféré.
+Évidemment Google propose son client aussi : Google Reader. S’il reste adapté pour les contenus pour lesquels on ne veut rien perdre. Il est moins agréable d’utilisation lorsque l’on s’abonne à des flux qui proposent une vingtaine de nouveaux liens par jour.
+Donc une fois que l’on a choisi son client, il suffit pour s’abonner de cliquer sur l’icône d’abonnement. Soit il est bien visible sur la page, soit tout en haut dans la barre des tâches.
+Ensuite lorsque vous utilisez votre client RSS les nouvelles provenant du blog se mettront à jour. Ainsi, il n’y a plus besoin d’aller sur les sites intéressants pour voir s’il n’y a rien de neuf. Ce sont eux qui vous donne leur dernières nouvelles.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
YAquaBubbles est un économiseur d’écran réalisé avec QuartzComposer. Il s’agissait d’un simple essai mais le résultat était plaisant.
+ +
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
YClock est un économiseur d’écran qui vous donne l’heure.i Il a trois thèmes clair, rouge et noir. Il utilise une base de QuartzComposition + du code objective-C pour la gestion du nombre d’images par seconde.
+ +
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Une gestion simple, sécurisée et portable de ses mots de passes web.
+Ici réalisée en elm:
Souvenez vous d’un seul mot de passe de bonne qualité, le reste suis.
+Ici vous trouverez :
+Dans peu de temps je créerai une application iPhone pour YPassword.
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ Une explication rapide du pourquoi il y a des erreurs de validation de mes pages.
+Je voulais utiliser box-shadows et border-radius
J’ai donc préféré avoir un approche pragamatique que dogmatique.
+Utiliser ces propriétés me fait perdre la validation CSS mais fonctionne très bien avec les navigateurs récents (Safari 4 et Firefox 3.5 au moment de l’écriture de ces lignes)
+Si vous n’utilisez pas ces navigateur les pages s’affichent correctement mais sans ces effets qui n’ont pour but que d’améliorer l’aspect général de la page.
+Par contre je suis plutôt un partisant de la validation et c’est pourquoi il y a toujours les liens. Tout valide à l’exception des propriétés commençant par -moz et -webkit.
+ ADA:
+
+
+ DdzFFzCqrhtAvdkmATx5Fm8NPJViDy85ZBw13p4XcNzVzvQg8e3vWLXq23JQWFxPEXK6Kvhaxxe7oJt4VMYHxpA2vtCFiP8fziohN6Yp
+
+ "+(escaped?code:escape(code,true))+"\n'+(escaped?code:escape(code,true))+"\n\n"+quote+"\n"};Renderer.prototype.html=function(html){return html};Renderer.prototype.heading=function(text,level,raw){return"
"+text+"
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+ +