14 lines
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14 lines
728 B
HTML
<h2 id="natural-transformation-examples-14">Natural Transformation Examples (1/4)</h2>
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<pre><code class="haskell small">data Tree a = Empty | Node a [Tree a]
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toTree :: [a] -> Tree a
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toTree [] = Empty
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toTree (x:xs) = Node x [toTree xs]</pre>
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</code>
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<p><code>toTree</code> is a natural transformation. It is also a morphism from <code>[]</code> to <code>Tree</code> in the Category of \(\Hask\) endofunctors.</p>
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<img style="float:left;width:30%" src="categories/img/mp/nattrans-list-tree.png" alt="natural transformation commutative diagram"/>
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<figure style="float:right;width:60%">
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<img style="width:40%" src="categories/img/mp/list-tree-endofunctor-morphism.png" alt="natural transformation commutative diagram"/>
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</figure>
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