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| <div class="section"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="fusion.support.pair"></a><a class="link" href="pair.html" title="pair">pair</a> |
| </h3></div></div></div> |
| <a name="fusion.support.pair.description"></a><h5> |
| <a name="id841265"></a> |
| <a class="link" href="pair.html#fusion.support.pair.description">Description</a> |
| </h5> |
| <p> |
| Fusion <code class="computeroutput"><span class="identifier">pair</span></code> type is a half |
| runtime pair. A half runtime pair is similar to a <a class="link" href="../adapted/std__pair.html" title="std::pair"><code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">pair</span></code></a>, |
| but, unlike <a class="link" href="../adapted/std__pair.html" title="std::pair"><code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">pair</span></code></a>, |
| the first type does not have data. It is used as elements in <a class="link" href="../container/map.html" title="map"><code class="computeroutput"><span class="identifier">map</span></code></a>s, for example. |
| </p> |
| <a name="fusion.support.pair.synopsis"></a><h5> |
| <a name="id841332"></a> |
| <a class="link" href="pair.html#fusion.support.pair.synopsis">Synopsis</a> |
| </h5> |
| <pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">First</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Second</span><span class="special">></span> |
| <span class="keyword">struct</span> <span class="identifier">pair</span><span class="special">;</span> |
| |
| <span class="keyword">namespace</span> <span class="identifier">result_of</span> |
| <span class="special">{</span> |
| <span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Pair</span><span class="special">></span> |
| <span class="keyword">struct</span> <span class="identifier">first</span><span class="special">;</span> |
| |
| <span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Pair</span><span class="special">></span> |
| <span class="keyword">struct</span> <span class="identifier">second</span><span class="special">;</span> |
| |
| <span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">First</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Second</span><span class="special">></span> |
| <span class="keyword">struct</span> <span class="identifier">make_pair</span><span class="special">;</span> |
| <span class="special">}</span> |
| |
| <span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">First</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Second</span><span class="special">></span> |
| <span class="keyword">typename</span> <span class="identifier">result_of</span><span class="special">::</span><span class="identifier">make_pair</span><span class="special"><</span><span class="identifier">First</span><span class="special">,</span><span class="identifier">Second</span><span class="special">>::</span><span class="identifier">type</span> |
| <span class="identifier">make_pair</span><span class="special">(</span><span class="identifier">Second</span> <span class="keyword">const</span> <span class="special">&);</span> |
| </pre> |
| <a name="fusion.support.pair.template_parameters"></a><h5> |
| <a name="id841628"></a> |
| <a class="link" href="pair.html#fusion.support.pair.template_parameters">Template parameters</a> |
| </h5> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Parameter |
| </p> |
| </th> |
| <th> |
| <p> |
| Description |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| First |
| </p> |
| </td> |
| <td> |
| <p> |
| The first type. This is purely a type. No data is held. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| Second |
| </p> |
| </td> |
| <td> |
| <p> |
| The second type. This contains data. |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <div class="variablelist"> |
| <p class="title"><b>Notation</b></p> |
| <dl> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">P</span></code></span></dt> |
| <dd><p> |
| Fusion pair type |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">p</span></code>, <code class="computeroutput"><span class="identifier">p2</span></code></span></dt> |
| <dd><p> |
| Fusion pairs |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">F</span></code>, <code class="computeroutput"><span class="identifier">S</span></code></span></dt> |
| <dd><p> |
| Arbitrary types |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">s</span></code></span></dt> |
| <dd><p> |
| Value of type <code class="computeroutput"><span class="identifier">S</span></code> |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">o</span></code></span></dt> |
| <dd><p> |
| Output stream |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">i</span></code></span></dt> |
| <dd><p> |
| Input stream |
| </p></dd> |
| </dl> |
| </div> |
| <a name="fusion.support.pair.expression_semantics"></a><h5> |
| <a name="id841857"></a> |
| <a class="link" href="pair.html#fusion.support.pair.expression_semantics">Expression Semantics</a> |
| </h5> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Expression |
| </p> |
| </th> |
| <th> |
| <p> |
| Semantics |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">P</span><span class="special">::</span><span class="identifier">first_type</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| The type of the first template parameter, <code class="computeroutput"><span class="identifier">F</span></code>, |
| equivalent to <code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">first</span><span class="special"><</span><span class="identifier">P</span><span class="special">>::</span><span class="identifier">type</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">P</span><span class="special">::</span><span class="identifier">second_type</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| The type of the second template parameter, <code class="computeroutput"><span class="identifier">S</span></code>, |
| equivalent to <code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">second</span><span class="special"><</span><span class="identifier">P</span><span class="special">>::</span><span class="identifier">type</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">P</span><span class="special">()</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Default construction. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">P</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Construct a pair given value for the second type, <code class="computeroutput"><span class="identifier">s</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">P</span><span class="special">(</span><span class="identifier">p2</span><span class="special">)</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Copy constructs a pair from another pair, <code class="computeroutput"><span class="identifier">p2</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">p</span><span class="special">.</span><span class="identifier">second</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Get the data from <code class="computeroutput"><span class="identifier">p1</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">p</span> <span class="special">=</span> |
| <span class="identifier">p2</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Assigns a pair, <code class="computeroutput"><span class="identifier">p1</span></code>, |
| from another pair, <code class="computeroutput"><span class="identifier">p2</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| make_pair<F>(s) |
| </p> |
| </td> |
| <td> |
| <p> |
| Make a pair given the first type, <code class="computeroutput"><span class="identifier">F</span></code>, |
| and a value for the second type, <code class="computeroutput"><span class="identifier">s</span></code>. |
| The second type assumes the type of <code class="computeroutput"><span class="identifier">s</span></code> |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">o</span> <span class="special"><<</span> |
| <span class="identifier">p</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Output <code class="computeroutput"><span class="identifier">p</span></code> to output |
| stream, <code class="computeroutput"><span class="identifier">o</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">i</span> <span class="special">>></span> |
| <span class="identifier">p</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Input <code class="computeroutput"><span class="identifier">p</span></code> from input |
| stream, <code class="computeroutput"><span class="identifier">i</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">p</span> <span class="special">==</span> |
| <span class="identifier">p2</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Tests two pairs for equality. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">p</span> <span class="special">!=</span> |
| <span class="identifier">p2</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Tests two pairs for inequality. |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <a name="fusion.support.pair.header"></a><h5> |
| <a name="id842460"></a> |
| <a class="link" href="pair.html#fusion.support.pair.header">Header</a> |
| </h5> |
| <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">support</span><span class="special">/</span><span class="identifier">pair</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">pair</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| </pre> |
| <a name="fusion.support.pair.example"></a><h5> |
| <a name="id842568"></a> |
| <a class="link" href="pair.html#fusion.support.pair.example">Example</a> |
| </h5> |
| <pre class="programlisting"><span class="identifier">pair</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">char</span><span class="special">></span> <span class="identifier">p</span><span class="special">(</span><span class="char">'X'</span><span class="special">);</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">p</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">make_pair</span><span class="special"><</span><span class="keyword">int</span><span class="special">>(</span><span class="char">'X'</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> |
| <span class="identifier">assert</span><span class="special">((</span><span class="identifier">p</span> <span class="special">==</span> <span class="identifier">make_pair</span><span class="special"><</span><span class="keyword">int</span><span class="special">>(</span><span class="char">'X'</span><span class="special">)));</span> |
| </pre> |
| </div> |
| <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> |
| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2001-2007 Joel de Guzman, Dan Marsden, Tobias |
| Schwinger<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>) |
| </p> |
| </div></td> |
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