16 lines
456 B
HTML
16 lines
456 B
HTML
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<h2 id="example-list">Example: List</h2>
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<ul>
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<li><code>[] :: * -> *</code> an <span class="yellow">Endofunctor</span></li>
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<li>\(⊙:M×M→M\) a nat. trans. (<code>join :: M (M a) -> M a</code>)</li>
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<li>\(η:I→M\) a nat. trans.</li>
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</ul>
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<pre class="haskell"><code>-- In Haskell ⊙ is "join" in "Control.Monad"
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join :: [[a]] -> [a]
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join = concat
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-- In Haskell the "return" function (unfortunate name)
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η :: a -> [a]
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η x = [x]</code></pre>
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