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Data-List-Lens.html
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Data-List-Lens.html
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>Data.List.Lens</title><link href="ocean.css" rel="stylesheet" type="text/css" title="Ocean" /><script src="haddock-util.js" type="text/javascript"></script><script type="text/javascript">//<![CDATA[
window.onload = function () {pageLoad();setSynopsis("mini_Data-List-Lens.html");};
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</script></head><body><div id="package-header"><ul class="links" id="page-menu"><li><a href="src/Data-List-Lens.html">Source</a></li><li><a href="index.html">Contents</a></li><li><a href="doc-index.html">Index</a></li></ul><p class="caption">lens-3.5: Lenses, Folds and Traversals</p></div><div id="content"><div id="module-header"><table class="info"><tr><th>Portability</th><td>portable</td></tr><tr><th>Stability</th><td>provisional</td></tr><tr><th>Maintainer</th><td>Edward Kmett <ekmett@gmail.com></td></tr><tr><th>Safe Haskell</th><td>None</td></tr></table><p class="caption">Data.List.Lens</p></div><div id="table-of-contents"><p class="caption">Contents</p><ul><li><a href="#g:1">Partial Lenses
</a></li></ul></div><div id="description"><p class="caption">Description</p><div class="doc"><p>Traversals for manipulating parts of a list.
</p></div></div><div id="synopsis"><p id="control.syn" class="caption expander" onclick="toggleSection('syn')">Synopsis</p><ul id="section.syn" class="hide" onclick="toggleSection('syn')"><li class="src short"><a href="#v:_head">_head</a> :: <a href="Control-Lens-IndexedTraversal.html#t:SimpleIndexedTraversal">SimpleIndexedTraversal</a> Int [a] a</li><li class="src short"><a href="#v:_tail">_tail</a> :: <a href="Control-Lens-Type.html#t:Simple">Simple</a> <a href="Control-Lens-Traversal.html#t:Traversal">Traversal</a> [a] [a]</li><li class="src short"><a href="#v:_last">_last</a> :: <a href="Control-Lens-IndexedTraversal.html#t:SimpleIndexedTraversal">SimpleIndexedTraversal</a> Int [a] a</li><li class="src short"><a href="#v:_init">_init</a> :: <a href="Control-Lens-Type.html#t:Simple">Simple</a> <a href="Control-Lens-Traversal.html#t:Traversal">Traversal</a> [a] [a]</li></ul></div><div id="interface"><h1 id="g:1">Partial Lenses
</h1><div class="top"><p class="src"><a name="v:_head" class="def">_head</a> :: <a href="Control-Lens-IndexedTraversal.html#t:SimpleIndexedTraversal">SimpleIndexedTraversal</a> Int [a] a<a href="src/Data-List-Lens.html#_head" class="link">Source</a></p><div class="doc"><p>A <code><a href="Control-Lens-Traversal.html#t:Traversal">Traversal</a></code> reading and writing to the <code>head</code> of a <em>non-empty</em> list.
</p><pre class="screen"><code class="prompt">>>> </code><strong class="userinput"><code>[1,2,3]^!?_head
</code></strong>1
</pre></div></div><div class="top"><p class="src"><a name="v:_tail" class="def">_tail</a> :: <a href="Control-Lens-Type.html#t:Simple">Simple</a> <a href="Control-Lens-Traversal.html#t:Traversal">Traversal</a> [a] [a]<a href="src/Data-List-Lens.html#_tail" class="link">Source</a></p><div class="doc"><p>A <code><a href="Control-Lens-Traversal.html#t:Traversal">Traversal</a></code> reading and writing to the <code>tail</code> of a <em>non-empty</em> list
</p><pre class="screen"><code class="prompt">>>> </code><strong class="userinput"><code>_tail .~ [3,4,5] $ [1,2]
</code></strong>[1,3,4,5]
</pre></div></div><div class="top"><p class="src"><a name="v:_last" class="def">_last</a> :: <a href="Control-Lens-IndexedTraversal.html#t:SimpleIndexedTraversal">SimpleIndexedTraversal</a> Int [a] a<a href="src/Data-List-Lens.html#_last" class="link">Source</a></p><div class="doc"><p>A <code><a href="Control-Lens-Traversal.html#t:Traversal">Traversal</a></code> reading and writing to the last element of a <em>non-empty</em> list
</p><pre class="screen"><code class="prompt">>>> </code><strong class="userinput"><code>[1,2]^!?_last
</code></strong>2
</pre></div></div><div class="top"><p class="src"><a name="v:_init" class="def">_init</a> :: <a href="Control-Lens-Type.html#t:Simple">Simple</a> <a href="Control-Lens-Traversal.html#t:Traversal">Traversal</a> [a] [a]<a href="src/Data-List-Lens.html#_init" class="link">Source</a></p><div class="doc"><p>A <code><a href="Control-Lens-Traversal.html#t:Traversal">Traversal</a></code> reading and replacing all but the a last element of a <em>non-empty</em> list
</p><pre class="screen"><code class="prompt">>>> </code><strong class="userinput"><code>[1,2,3,4]^!?_init
</code></strong>[1,2,3]
</pre></div></div></div></div><div id="footer"><p>Produced by <a href="http://www.haskell.org/haddock/">Haddock</a> version 2.13.1</p></div></body></html>