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<a name="boost.xpressive.reference"></a><div class="titlepage"></div>
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<h2><span class="refentrytitle">Struct template reference</span></h2>
<p>boost::xpressive::reference — <code class="computeroutput">reference<></code> is a lazy wrapper for a reference that can be used in xpressive semantic actions. </p>
</div>
<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: <<a class="link" href="../../xpressive/reference.html#header.boost.xpressive.regex_actions_hpp" title="Header <boost/xpressive/regex_actions.hpp>">boost/xpressive/regex_actions.hpp</a>>
</span><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> T<span class="special">></span>
<span class="keyword">struct</span> <a class="link" href="reference.html" title="Struct template reference">reference</a> <span class="special">:</span> <span class="keyword">public</span> proto::extends< proto::terminal< reference_wrapper< T > >::type, reference< T > >
<span class="special">{</span>
<span class="comment">// <a class="link" href="reference.html#boost.xpressive.referenceconstruct-copy-destruct">construct/copy/destruct</a></span>
<span class="keyword">explicit</span> <a class="link" href="reference.html#idm45506840445376-bb"><span class="identifier">reference</span></a><span class="special">(</span><span class="identifier">T</span> <span class="special">&</span><span class="special">)</span><span class="special">;</span>
<span class="comment">// <a class="link" href="reference.html#idm45506840447520-bb">public member functions</a></span>
<span class="identifier">T</span> <span class="special">&</span> <a class="link" href="reference.html#idm45506840446960-bb"><span class="identifier">get</span></a><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
<span class="special">}</span><span class="special">;</span></pre></div>
<div class="refsect1">
<a name="idm45555020527728"></a><h2>Description</h2>
<p>
Here is an example of how to use <code class="computeroutput">reference<></code> to create a lazy reference to an existing object so it can be read and written in an xpressive semantic action.</p>
<pre class="programlisting"><span class="keyword">using</span> <span class="keyword">namespace</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">xpressive</span><span class="special">;</span>
<span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">,</span> <span class="keyword">int</span><span class="special">></span> <span class="identifier">result</span><span class="special">;</span>
<span class="identifier">reference</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">,</span> <span class="keyword">int</span><span class="special">></span> <span class="special">></span> <span class="identifier">result_ref</span><span class="special">(</span><span class="identifier">result</span><span class="special">)</span><span class="special">;</span>
<span class="comment">// Match a word and an integer, separated by =>,</span>
<span class="comment">// and then stuff the result into a std::map<></span>
<span class="identifier">sregex</span> <span class="identifier">pair</span> <span class="special">=</span> <span class="special">(</span> <span class="special">(</span><span class="identifier">s1</span><span class="special">=</span> <span class="special">+</span><span class="identifier">_w</span><span class="special">)</span> <span class="special">>></span> <span class="string">"=>"</span> <span class="special">>></span> <span class="special">(</span><span class="identifier">s2</span><span class="special">=</span> <span class="special">+</span><span class="identifier">_d</span><span class="special">)</span> <span class="special">)</span>
<span class="special">[</span> <span class="identifier">result_ref</span><span class="special">[</span><span class="identifier">s1</span><span class="special">]</span> <span class="special">=</span> <span class="identifier">as</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span><span class="special">(</span><span class="identifier">s2</span><span class="special">)</span> <span class="special">]</span><span class="special">;</span>
</pre>
<p> </p>
<div class="refsect2">
<a name="idm45555020482416"></a><h3>Template Parameters</h3>
<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
<pre class="literallayout"><span class="keyword">typename</span> T</pre>
<p>The type of the referent.</p>
</li></ol></div>
</div>
<div class="refsect2">
<a name="idm45555020479280"></a><h3>
<a name="boost.xpressive.referenceconstruct-copy-destruct"></a><code class="computeroutput">reference</code>
public
construct/copy/destruct</h3>
<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
<pre class="literallayout"><span class="keyword">explicit</span> <a name="idm45506840445376-bb"></a><span class="identifier">reference</span><span class="special">(</span><span class="identifier">T</span> <span class="special">&</span> t<span class="special">)</span><span class="special">;</span></pre>Store a reference to <code class="computeroutput">t</code>. <p>
</p>
<div class="variablelist"><table border="0" class="variablelist compact">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
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<td><p><span class="term">Parameters:</span></p></td>
<td><div class="variablelist"><table border="0" class="variablelist compact">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody><tr>
<td><p><span class="term"><code class="computeroutput">t</code></span></p></td>
<td><p>Reference to object </p></td>
</tr></tbody>
</table></div></td>
</tr></tbody>
</table></div>
</li></ol></div>
</div>
<div class="refsect2">
<a name="idm45555020467392"></a><h3>
<a name="idm45506840447520-bb"></a><code class="computeroutput">reference</code> public member functions</h3>
<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem">
<pre class="literallayout"><span class="identifier">T</span> <span class="special">&</span> <a name="idm45506840446960-bb"></a><span class="identifier">get</span><span class="special">(</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span></pre>Fetch the stored value. </li></ol></div>
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<td align="right"><div class="copyright-footer">Copyright © 2007 Eric Niebler<p>
Distributed under the Boost Software License, Version 1.0. (See accompanying
file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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