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| <div class="titlepage"><div><div><h5 class="title"> |
| <a name="spirit.qi.reference.directive.matches"></a><a class="link" href="matches.html" title="Test if Parser Succeeded (matches[])">Test if Parser |
| Succeeded (<code class="computeroutput"><span class="identifier">matches</span><span class="special">[]</span></code>)</a> |
| </h5></div></div></div> |
| <a name="spirit.qi.reference.directive.matches.description"></a><h6> |
| <a name="id895714"></a> |
| <a class="link" href="matches.html#spirit.qi.reference.directive.matches.description">Description</a> |
| </h6> |
| <p> |
| The <code class="computeroutput"><span class="identifier">matches</span><span class="special">[]</span></code> |
| directive executes the embedded parser and returns whether it succeeded |
| matching. |
| </p> |
| <a name="spirit.qi.reference.directive.matches.header"></a><h6> |
| <a name="id895752"></a> |
| <a class="link" href="matches.html#spirit.qi.reference.directive.matches.header">Header</a> |
| </h6> |
| <pre class="programlisting"><span class="comment">// forwards to <boost/spirit/home/qi/directive/matches.hpp> |
| </span><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">spirit</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">qi_matches</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| </pre> |
| <p> |
| Also, see <a class="link" href="../../../structure/include.html" title="Include">Include Structure</a>. |
| </p> |
| <a name="spirit.qi.reference.directive.matches.namespace"></a><h6> |
| <a name="id895826"></a> |
| <a class="link" href="matches.html#spirit.qi.reference.directive.matches.namespace">Namespace</a> |
| </h6> |
| <div class="informaltable"><table class="table"> |
| <colgroup><col></colgroup> |
| <thead><tr><th> |
| <p> |
| Name |
| </p> |
| </th></tr></thead> |
| <tbody><tr><td> |
| <p> |
| <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">matches</span> <span class="comment">// |
| alias: boost::spirit::qi::matches</span></code> |
| </p> |
| </td></tr></tbody> |
| </table></div> |
| <a name="spirit.qi.reference.directive.matches.model_of"></a><h6> |
| <a name="id895905"></a> |
| <a class="link" href="matches.html#spirit.qi.reference.directive.matches.model_of">Model |
| of</a> |
| </h6> |
| <div class="blockquote"><blockquote class="blockquote"><p> |
| <a class="link" href="../parser_concepts/unaryparser.html" title="UnaryParser"><code class="computeroutput"><span class="identifier">UnaryParser</span></code></a> |
| </p></blockquote></div> |
| <div class="variablelist"> |
| <p class="title"><b>Notation</b></p> |
| <dl> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">a</span></code></span></dt> |
| <dd><p> |
| A <a class="link" href="../parser_concepts/parser.html" title="Parser"><code class="computeroutput"><span class="identifier">Parser</span></code></a>. |
| </p></dd> |
| </dl> |
| </div> |
| <a name="spirit.qi.reference.directive.matches.expression_semantics"></a><h6> |
| <a name="id895974"></a> |
| <a class="link" href="matches.html#spirit.qi.reference.directive.matches.expression_semantics">Expression |
| Semantics</a> |
| </h6> |
| <p> |
| Semantics of an expression is defined only where it differs from, or |
| is not defined in <a class="link" href="../parser_concepts/unaryparser.html" title="UnaryParser"><code class="computeroutput"><span class="identifier">UnaryParser</span></code></a>. |
| </p> |
| <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">matches</span><span class="special">[</span><span class="identifier">a</span><span class="special">]</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Execute the subject parser <code class="computeroutput"><span class="identifier">a</span></code>, |
| and return as its attribute whether it succeeded. The directive |
| itself does always succeed. |
| </p> |
| </td> |
| </tr></tbody> |
| </table></div> |
| <a name="spirit.qi.reference.directive.matches.attributes"></a><h6> |
| <a name="id896080"></a> |
| <a class="link" href="matches.html#spirit.qi.reference.directive.matches.attributes">Attributes</a> |
| </h6> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Expression |
| </p> |
| </th> |
| <th> |
| <p> |
| Attribute |
| </p> |
| </th> |
| </tr></thead> |
| <tbody><tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">matches</span><span class="special">[</span><span class="identifier">a</span><span class="special">]</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="keyword">bool</span></code> |
| </p> |
| </td> |
| </tr></tbody> |
| </table></div> |
| <a name="spirit.qi.reference.directive.matches.complexity"></a><h6> |
| <a name="id896172"></a> |
| <a class="link" href="matches.html#spirit.qi.reference.directive.matches.complexity">Complexity</a> |
| </h6> |
| <div class="blockquote"><blockquote class="blockquote"><p> |
| The complexity is defined by the complexity of the subject parser, |
| <code class="computeroutput"><span class="identifier">a</span></code> |
| </p></blockquote></div> |
| <a name="spirit.qi.reference.directive.matches.example"></a><h6> |
| <a name="id896199"></a> |
| <a class="link" href="matches.html#spirit.qi.reference.directive.matches.example">Example</a> |
| </h6> |
| <div class="note"><table border="0" summary="Note"> |
| <tr> |
| <td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../images/note.png"></td> |
| <th align="left">Note</th> |
| </tr> |
| <tr><td align="left" valign="top"><p> |
| The test harness for the example(s) below is presented in the <a class="link" href="../basics.html#spirit.qi.reference.basics.examples">Basics Examples</a> |
| section. |
| </p></td></tr> |
| </table></div> |
| <p> |
| Some using declarations: |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">qi</span><span class="special">::</span><span class="identifier">matches</span><span class="special">;</span> |
| <span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">qi</span><span class="special">::</span><span class="identifier">int_</span><span class="special">;</span> |
| </pre> |
| <p> |
| </p> |
| <p> |
| This parser tries to match an <code class="computeroutput"><span class="keyword">int</span></code> |
| and returns <code class="computeroutput"><span class="keyword">true</span></code> a its attribute |
| as it succeeded matching: |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="keyword">bool</span> <span class="identifier">result</span> <span class="special">=</span> <span class="keyword">false</span><span class="special">;</span> |
| <span class="identifier">test_parser_attr</span><span class="special">(</span><span class="string">"345"</span><span class="special">,</span> <span class="identifier">matches</span><span class="special">[</span><span class="identifier">int_</span><span class="special">],</span> <span class="identifier">result</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">std</span><span class="special">::</span><span class="identifier">boolalpha</span> <span class="special"><<</span> <span class="identifier">result</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="comment">// should print: true</span></pre> |
| <p> |
| </p> |
| <p> |
| This parser tries to match an <code class="computeroutput"><span class="keyword">int</span></code> |
| as well and returns <code class="computeroutput"><span class="keyword">false</span></code> |
| as its attribute as it fails matching: |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="identifier">result</span> <span class="special">=</span> <span class="keyword">true</span><span class="special">;</span> |
| <span class="identifier">test_parser_attr</span><span class="special">(</span><span class="string">"abc"</span><span class="special">,</span> <span class="identifier">matches</span><span class="special">[</span><span class="identifier">int_</span><span class="special">],</span> <span class="identifier">result</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">std</span><span class="special">::</span><span class="identifier">boolalpha</span> <span class="special"><<</span> <span class="identifier">result</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="comment">// should print: false |
| </span></pre> |
| <p> |
| </p> |
| </div> |
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| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2001-2010 Joel de Guzman, Hartmut Kaiser<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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