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| <div class="titlepage"><div><div><h5 class="title"> |
| <a name="fusion.algorithm.transformation.metafunctions.filter_if"></a><a class="link" href="filter_if.html" title="filter_if">filter_if</a> |
| </h5></div></div></div> |
| <a name="fusion.algorithm.transformation.metafunctions.filter_if.description"></a><h6> |
| <a name="id1038350"></a> |
| <a class="link" href="filter_if.html#fusion.algorithm.transformation.metafunctions.filter_if.description">Description</a> |
| </h6> |
| <p> |
| Returns the result type of <a class="link" href="../functions/filter_if.html" title="filter_if"><code class="computeroutput"><span class="identifier">filter_if</span></code></a> given the sequence |
| and unary <a href="http://www.boost.org/libs/mpl/doc/refmanual/lambda-expression.html" target="_top">MPL |
| Lambda Expression</a> predicate type. |
| </p> |
| <a name="fusion.algorithm.transformation.metafunctions.filter_if.synopsis"></a><h6> |
| <a name="id1038381"></a> |
| <a class="link" href="filter_if.html#fusion.algorithm.transformation.metafunctions.filter_if.synopsis">Synopsis</a> |
| </h6> |
| <pre class="programlisting"><span class="keyword">template</span><span class="special"><</span> |
| <span class="keyword">typename</span> <span class="identifier">Sequence</span><span class="special">,</span> |
| <span class="keyword">typename</span> <span class="identifier">Pred</span> |
| <span class="special">></span> |
| <span class="keyword">struct</span> <span class="identifier">filter_if</span> |
| <span class="special">{</span> |
| <span class="keyword">typedef</span> <span class="emphasis"><em>unspecified</em></span> <span class="identifier">type</span><span class="special">;</span> |
| <span class="special">};</span> |
| </pre> |
| <div class="table"> |
| <a name="id1038466"></a><p class="title"><b>Table 1.84. Parameter</b></p> |
| <div class="table-contents"><table class="table" summary="Parameter"> |
| <colgroup> |
| <col> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Parameter |
| </p> |
| </th> |
| <th> |
| <p> |
| Requirement |
| </p> |
| </th> |
| <th> |
| <p> |
| Description |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">Sequence</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| A model of <a class="link" href="../../../sequence/concepts/forward_sequence.html" title="Forward Sequence">Forward |
| Sequence</a> |
| </p> |
| </td> |
| <td> |
| <p> |
| Operation's argument |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">Pred</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| A unary <a href="http://www.boost.org/libs/mpl/doc/refmanual/lambda-expression.html" target="_top">MPL |
| Lambda Expression</a> |
| </p> |
| </td> |
| <td> |
| <p> |
| Type to retain |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| </div> |
| <br class="table-break"><a name="fusion.algorithm.transformation.metafunctions.filter_if.expression_semantics"></a><h6> |
| <a name="id1038591"></a> |
| <a class="link" href="filter_if.html#fusion.algorithm.transformation.metafunctions.filter_if.expression_semantics">Expression |
| Semantics</a> |
| </h6> |
| <pre class="programlisting"><a class="link" href="filter_if.html" title="filter_if"><code class="computeroutput"><span class="identifier">result_of</span><span class="special">::</span><span class="identifier">filter_if</span></code></a><span class="special"><</span><span class="identifier">Sequence</span><span class="special">,</span> <span class="identifier">Pred</span><span class="special">>::</span><span class="identifier">type</span> |
| </pre> |
| <p> |
| <span class="bold"><strong>Return type</strong></span>: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" type="disc"> |
| <li class="listitem"> |
| A model of <a class="link" href="../../../sequence/concepts/forward_sequence.html" title="Forward Sequence">Forward |
| Sequence</a>. |
| </li> |
| <li class="listitem"> |
| A model of <a class="link" href="../../../sequence/concepts/associative_sequence.html" title="Associative Sequence">Associative |
| Sequence</a> if <code class="computeroutput"><span class="identifier">Sequence</span></code> |
| implements the <a class="link" href="../../../sequence/concepts/associative_sequence.html" title="Associative Sequence">Associative |
| Sequence</a> model. |
| </li> |
| </ul></div> |
| <p> |
| <span class="bold"><strong>Semantics</strong></span>: Returns a sequence containing |
| the elements of <code class="computeroutput"><span class="identifier">Sequence</span></code> |
| for which <code class="computeroutput"><span class="identifier">Pred</span></code> evaluates |
| to <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mpl</span><span class="special">::</span><span class="identifier">true_</span></code>. |
| </p> |
| <a name="fusion.algorithm.transformation.metafunctions.filter_if.complexity"></a><h6> |
| <a name="id1038741"></a> |
| <a class="link" href="filter_if.html#fusion.algorithm.transformation.metafunctions.filter_if.complexity">Complexity</a> |
| </h6> |
| <p> |
| Constant. |
| </p> |
| <a name="fusion.algorithm.transformation.metafunctions.filter_if.header"></a><h6> |
| <a name="id1038760"></a> |
| <a class="link" href="filter_if.html#fusion.algorithm.transformation.metafunctions.filter_if.header">Header</a> |
| </h6> |
| <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">algorithm</span><span class="special">/</span><span class="identifier">transformation</span><span class="special">/</span><span class="identifier">filter_if</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">filter_if</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| </pre> |
| </div> |
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| <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>) |
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