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| <div class="titlepage"><div><div><h5 class="title"> |
| <a name="spirit.karma.reference.directive.duplicate"></a><a class="link" href="duplicate.html" title="Duplicate Attribute (duplicate[])">Duplicate |
| Attribute (<code class="computeroutput"><span class="identifier">duplicate</span><span class="special">[]</span></code>)</a> |
| </h5></div></div></div> |
| <a name="spirit.karma.reference.directive.duplicate.description"></a><h6> |
| <a name="id1054338"></a> |
| <a class="link" href="duplicate.html#spirit.karma.reference.directive.duplicate.description">Description</a> |
| </h6> |
| <p> |
| The directive <code class="computeroutput"><span class="identifier">duplicate</span><span class="special">[]</span></code> duplicates its attribute to all elements |
| of the embedded generator if this is a sequence generator. Otherwise |
| it does nothing. |
| </p> |
| <a name="spirit.karma.reference.directive.duplicate.header"></a><h6> |
| <a name="id1054366"></a> |
| <a class="link" href="duplicate.html#spirit.karma.reference.directive.duplicate.header">Header</a> |
| </h6> |
| <pre class="programlisting"><span class="comment">// forwards to <boost/spirit/home/karma/directive/duplicate.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">karma_duplicate</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> |
| <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">duplicate</span> <span class="comment">// |
| alias: boost::spirit::karma::duplicate</span></code> |
| </p> |
| </td></tr></tbody> |
| </table></div> |
| <a name="spirit.karma.reference.directive.duplicate.model_of"></a><h6> |
| <a name="id1054506"></a> |
| <a class="link" href="duplicate.html#spirit.karma.reference.directive.duplicate.model_of">Model |
| of</a> |
| </h6> |
| <div class="blockquote"><blockquote class="blockquote"><p> |
| <a class="link" href="../generator_concepts/unarygenerator.html" title="UnaryGenerator"><code class="computeroutput"><span class="identifier">UnaryGenerator</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 generator object |
| </p></dd> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">A</span></code></span></dt> |
| <dd><p> |
| Attribute type of generator <code class="computeroutput"><span class="identifier">a</span></code> |
| </p></dd> |
| </dl> |
| </div> |
| <a name="spirit.karma.reference.directive.duplicate.expression_semantics"></a><h6> |
| <a name="id1054594"></a> |
| <a class="link" href="duplicate.html#spirit.karma.reference.directive.duplicate.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="../generator_concepts/unarygenerator.html" title="UnaryGenerator"><code class="computeroutput"><span class="identifier">UnaryGenerator</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">duplicate</span><span class="special">[</span><span class="identifier">a</span><span class="special">]</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| The <code class="computeroutput"><span class="identifier">duplicate</span></code> |
| directive duplicates the supplied attribute for all elements |
| of a embedded sequence generator. For all other types of embedded |
| generators it has no effect. It succeeds as long as its embedded |
| generator does not fail. |
| </p> |
| </td> |
| </tr></tbody> |
| </table></div> |
| <a name="spirit.karma.reference.directive.duplicate.attributes"></a><h6> |
| <a name="id1054703"></a> |
| <a class="link" href="duplicate.html#spirit.karma.reference.directive.duplicate.attributes">Attributes</a> |
| </h6> |
| <p> |
| See <a class="link" href="../../quick_reference/compound_attribute_rules.html#spirit.karma.quick_reference.compound_attribute_rules.notation">Compound |
| Attribute Notation</a>. |
| </p> |
| <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">duplicate</span><span class="special">[</span><span class="identifier">a</span><span class="special">]</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| |
| </p> |
| <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="identifier">a</span><span class="special">:</span> <span class="identifier">A</span> <span class="special">--></span> <span class="identifier">duplicate</span><span class="special">[</span><span class="identifier">a</span><span class="special">]:</span> <span class="identifier">A</span> |
| <span class="identifier">a</span><span class="special">:</span> <span class="identifier">tuple</span><span class="special"><</span><span class="identifier">A</span><span class="special">,</span> <span class="identifier">A</span><span class="special">,</span> <span class="special">...></span> <span class="special">--></span> <span class="identifier">duplicate</span><span class="special">[</span><span class="identifier">a</span><span class="special">]:</span> <span class="identifier">A</span> |
| <span class="identifier">a</span><span class="special">:</span> <span class="identifier">Unused</span> <span class="special">--></span> <span class="identifier">duplicate</span><span class="special">[</span><span class="identifier">a</span><span class="special">]:</span> <span class="identifier">Unused</span></pre> |
| <p> |
| </p> |
| </td> |
| </tr></tbody> |
| </table></div> |
| <p> |
| If the embedded generator of the <code class="computeroutput"><span class="identifier">duplicate</span><span class="special">[]</span></code> directive is a sequence it is expected |
| that all elements of this sequence expose either the same attribute type, |
| an compatible attribute type, or <code class="computeroutput"><span class="identifier">unused</span></code>. |
| In this case, the <code class="computeroutput"><span class="identifier">duplicate</span><span class="special">[]</span></code> directive exposes the attribute type |
| of its first element. The behavior of the <code class="computeroutput"><span class="identifier">duplicate</span><span class="special">[]</span></code> directive is undefined if the elements |
| of an embedded sequence do not expose the same attributes. Most likely, |
| the corresponding expression will not compile. |
| </p> |
| <a name="spirit.karma.reference.directive.duplicate.complexity"></a><h6> |
| <a name="id1054982"></a> |
| <a class="link" href="duplicate.html#spirit.karma.reference.directive.duplicate.complexity">Complexity</a> |
| </h6> |
| <div class="blockquote"><blockquote class="blockquote"><p> |
| The overall complexity of the <code class="computeroutput"><span class="identifier">duplicate</span><span class="special">[]</span></code> directive depends on the complexity |
| of the embedded generator. |
| </p></blockquote></div> |
| <a name="spirit.karma.reference.directive.duplicate.example"></a><h6> |
| <a name="id1055014"></a> |
| <a class="link" href="duplicate.html#spirit.karma.reference.directive.duplicate.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="../karma_basics.html#spirit.karma.reference.karma_basics.examples">Basics Examples</a> |
| section. |
| </p></td></tr> |
| </table></div> |
| <p> |
| Some includes: |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><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">karma</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">spirit</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">phoenix_core</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">spirit</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">phoenix_operator</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">std_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">iostream</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">string</span><span class="special">></span> |
| </pre> |
| <p> |
| </p> |
| <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">karma</span><span class="special">::</span><span class="identifier">double_</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">karma</span><span class="special">::</span><span class="identifier">duplicate</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">karma</span><span class="special">::</span><span class="identifier">space</span><span class="special">;</span> |
| </pre> |
| <p> |
| </p> |
| <p> |
| Basic usage of the <code class="computeroutput"><span class="identifier">duplicate</span></code> |
| generators: |
| </p> |
| <p> |
| |
| </p> |
| <pre class="programlisting"><span class="identifier">test_generator_attr</span><span class="special">(</span><span class="string">"2.02.0"</span><span class="special">,</span> <span class="identifier">duplicate</span><span class="special">[</span><span class="identifier">double_</span> <span class="special"><<</span> <span class="identifier">double_</span><span class="special">],</span> <span class="number">2.0</span><span class="special">);</span> |
| <span class="identifier">test_generator_attr_delim</span><span class="special">(</span><span class="string">"2.0 2.0 "</span><span class="special">,</span> <span class="identifier">duplicate</span><span class="special">[</span><span class="identifier">double_</span> <span class="special"><<</span> <span class="identifier">double_</span><span class="special">],</span> <span class="identifier">space</span><span class="special">,</span> <span class="number">2.0</span><span class="special">);</span> |
| </pre> |
| <p> |
| </p> |
| </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 © 2001-2010 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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