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<center><h1>Module <a href="type_Option.html">Option</a></h1></center>
<br>
<pre><span class="keyword">module</span> Option: <code class="code">sig</code> <a href="Option.html">..</a> <code class="code">end</code></pre>Functions for the option type.
<p>
Options are an Ocaml standard type that can be either <code class="code">None</code> (undefined)
or <code class="code">Some x</code> where x can be any value. Options are widely used in Ocaml
to represent undefined values (a little like NULL in C, but in a type
and memory safe way). This module adds some functions for working with
options.<br>
<hr width="100%">
<pre><span class="keyword">val</span> <a name="VALmay"></a>may : <code class="type">('a -> unit) -> 'a option -> unit</code></pre><div class="info">
<code class="code">may f (Some x)</code> calls <code class="code">f x</code> and <code class="code">may f None</code> does nothing.<br>
</div>
<pre><span class="keyword">val</span> <a name="VALmap"></a>map : <code class="type">('a -> 'b) -> 'a option -> 'b option</code></pre><div class="info">
<code class="code">map f (Some x)</code> returns <code class="code">Some (f x)</code> and <code class="code">map None</code> returns <code class="code">None</code>.<br>
</div>
<pre><span class="keyword">val</span> <a name="VALdefault"></a>default : <code class="type">'a -> 'a option -> 'a</code></pre><div class="info">
<code class="code">default x (Some v)</code> returns <code class="code">v</code> and <code class="code">default x None</code> returns <code class="code">x</code>.<br>
</div>
<pre><span class="keyword">val</span> <a name="VALmap_default"></a>map_default : <code class="type">('a -> 'b) -> 'b -> 'a option -> 'b</code></pre><div class="info">
<code class="code">map_default f x (Some v)</code> returns <code class="code">f v</code> and <code class="code">map_default f x None</code>
returns <code class="code">x</code>.<br>
</div>
<pre><span class="keyword">val</span> <a name="VALis_none"></a>is_none : <code class="type">'a option -> bool</code></pre><div class="info">
<code class="code">is_none None</code> returns <code class="code">true</code> otherwise it returns <code class="code">false</code>.<br>
</div>
<pre><span class="keyword">val</span> <a name="VALis_some"></a>is_some : <code class="type">'a option -> bool</code></pre><div class="info">
<code class="code">is_some (Some x)</code> returns <code class="code">true</code> otherwise it returns <code class="code">false</code>.<br>
</div>
<pre><span class="keyword">val</span> <a name="VALget"></a>get : <code class="type">'a option -> 'a</code></pre><div class="info">
<code class="code">get (Some x)</code> returns <code class="code">x</code> and <code class="code">get None</code> raises <code class="code">No_value</code>.<br>
</div>
<pre><span class="keyword">exception</span> <a name="EXCEPTIONNo_value"></a>No_value</pre>
<div class="info">
Raised when calling <code class="code">get None</code>.<br>
</div>
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distrib
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Mandriva
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2010.0
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i586
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media
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contrib-release
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by-pkgid
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6fd5939a63d29067c5ab016a476cd3df
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files
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51
