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<div class="section" id="inserter">
<h1><a class="toc-backref" href="./algorithms-concepts.html#id390" name="inserter">Inserter</a></h1>
<div class="section" id="inserter-description">
<h3><a class="subsection-title" href="#description" name="description">Description</a></h3>
<p>An <a class="reference" href="./inserter.html">Inserter</a> is a compile-time substitute for STL <a class="reference" href="http://www.sgi.com/tech/stl/OutputIterator.html" target="_top">Output Iterator</a>. 
Under the hood, it's simply a type holding 
two entities: a <em>state</em> and an <em>operation</em>. When passed to a 
<a class="reference" href="./transformation-algorithms.html">transformation algorithm</a>, the inserter's binary operation is
invoked for every element that would normally be written into the 
output iterator, with the element itself (as the second
argument) and the result of the previous operation's invocation — or,
for the very first element, the inserter's initial state.</p>
<p>Technically, instead of taking a single inserter parameter,
<a class="reference" href="./transformation-algorithms.html">transformation algorithms</a> could accept the state and the &quot;output&quot;
operation separately. Grouping these in a single parameter entity, 
however, brings the algorithms semantically and syntactically closer to 
their STL counterparts, significantly simplifying many of the common 
use cases.</p>
</div>
<div class="section" id="valid-expressions">
<h3><a class="subsection-title" href="#valid-expressions" name="valid-expressions">Valid expressions</a></h3>
<p>In the following table and subsequent specifications, <tt class="literal"><span class="pre">in</span></tt> is a model of <a class="reference" href="./inserter.html">Inserter</a>.</p>
<table border="1" class="table">
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<col width="43%" />
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<tr><th>Expression</th>
<th>Type</th>
</tr>
</thead>
<tbody valign="top">
<tr><td><tt class="literal"><span class="pre">in::state</span></tt></td>
<td>Any type</td>
</tr>
<tr><td><tt class="literal"><span class="pre">in::operation</span></tt></td>
<td>Binary <a class="reference" href="./lambda-expression.html">Lambda Expression</a></td>
</tr>
</tbody>
</table>
</div>
<div class="section" id="inserter-expression-semantics">
<h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3>
<table border="1" class="table">
<colgroup>
<col width="35%" />
<col width="65%" />
</colgroup>
<thead valign="bottom">
<tr><th>Expression</th>
<th>Semantics</th>
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<tr><td><tt class="literal"><span class="pre">in::state</span></tt></td>
<td>The inserter's initial state.</td>
</tr>
<tr><td><tt class="literal"><span class="pre">in::operation</span></tt></td>
<td>The inserter's &quot;output&quot; operation.</td>
</tr>
</tbody>
</table>
</div>
<div class="section" id="inserter-example">
<h3><a class="subsection-title" href="#example" name="example">Example</a></h3>
<pre class="literal-block">
typedef <a href="./transform.html" class="identifier">transform</a>&lt;
      <a href="./range-c.html" class="identifier">range_c</a>&lt;int,0,10&gt;
    , <a href="./plus.html" class="identifier">plus</a>&lt;_1,_1&gt;
    , <a href="./back-inserter.html" class="identifier">back_inserter</a>&lt; vector0&lt;&gt; &gt;
    &gt;::type result;
</pre>
</div>
<div class="section" id="inserter-models">
<h3><a class="subsection-title" href="#models" name="models">Models</a></h3>
<ul class="simple">
<li><a class="refentry reference" href="./inserters-inserter.html"><tt class="refentry literal"><span class="pre">inserter</span></tt></a></li>
<li><a class="refentry reference" href="./front-inserter.html"><tt class="refentry literal"><span class="pre">front_inserter</span></tt></a></li>
<li><a class="refentry reference" href="./back-inserter.html"><tt class="refentry literal"><span class="pre">back_inserter</span></tt></a></li>
</ul>
</div>
<div class="section" id="inserter-see-also">
<h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3>
<p><a class="reference" href="./algorithms.html">Algorithms</a>, <a class="reference" href="./transformation-algorithms.html">Transformation Algorithms</a>, <a class="refentry reference" href="./inserters-inserter.html"><tt class="refentry literal"><span class="pre">inserter</span></tt></a>, <a class="refentry reference" href="./front-inserter.html"><tt class="refentry literal"><span class="pre">front_inserter</span></tt></a>, <a class="refentry reference" href="./back-inserter.html"><tt class="refentry literal"><span class="pre">back_inserter</span></tt></a></p>
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