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| <div class="section"> |
| <div class="titlepage"><div><div><h5 class="title"> |
| <a name="spirit.advanced.customize.auto.create_generator"></a><a class="link" href="create_generator.html" title="Define a Custom Attribute Mapping for a Generator">Define |
| a Custom Attribute Mapping for a Generator</a> |
| </h5></div></div></div> |
| <a name="spirit.advanced.customize.auto.create_generator.create_generator"></a><h6> |
| <a name="id1201435"></a> |
| <a class="link" href="create_generator.html#spirit.advanced.customize.auto.create_generator.create_generator">create_generator</a> |
| </h6> |
| <p> |
| The template <code class="computeroutput"><span class="identifier">create_generator</span></code> |
| is a type used as an customization point. It is invoked by the <span class="emphasis"><em>Karma</em></span> |
| <a class="link" href="../../../karma/reference/generate_api/create_generator.html" title="API for Automatic Generator Creation"><code class="computeroutput"><span class="identifier">create_generator</span></code></a> API function |
| in order to create a custom mapping of the given data type to a generator |
| expression. This generator expression will be returned from <a class="link" href="../../../karma/reference/generate_api/create_generator.html" title="API for Automatic Generator Creation"><code class="computeroutput"><span class="identifier">create_generator</span></code></a> whenever the |
| given data type is encountered. |
| </p> |
| <a name="spirit.advanced.customize.auto.create_generator.module_headers"></a><h6> |
| <a name="id1201484"></a> |
| <a class="link" href="create_generator.html#spirit.advanced.customize.auto.create_generator.module_headers">Module |
| Headers</a> |
| </h6> |
| <pre class="programlisting"><span class="comment">// forwards to <boost/spirit/home/karma/auto.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_auto</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.advanced.customize.auto.create_generator.namespace"></a><h6> |
| <a name="id1201563"></a> |
| <a class="link" href="create_generator.html#spirit.advanced.customize.auto.create_generator.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">traits</span></code> |
| </p> |
| </td></tr></tbody> |
| </table></div> |
| <a name="spirit.advanced.customize.auto.create_generator.synopsis"></a><h6> |
| <a name="id1201641"></a> |
| <a class="link" href="create_generator.html#spirit.advanced.customize.auto.create_generator.synopsis">Synopsis</a> |
| </h6> |
| <pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Enable</span><span class="special">></span> |
| <span class="keyword">struct</span> <span class="identifier">create_generator</span> |
| <span class="special">{</span> |
| <span class="keyword">typedef</span> <span class="special"><</span><span class="identifier">unspecified</span><span class="special">></span> <span class="identifier">type</span><span class="special">;</span> |
| <span class="keyword">static</span> <span class="identifier">type</span> <span class="keyword">const</span><span class="special">&</span> <span class="identifier">call</span><span class="special">();</span> |
| <span class="special">};</span> |
| </pre> |
| <a name="spirit.advanced.customize.auto.create_generator.template_parameters"></a><h6> |
| <a name="id1201766"></a> |
| <a class="link" href="create_generator.html#spirit.advanced.customize.auto.create_generator.template_parameters">Template |
| parameters</a> |
| </h6> |
| <div class="informaltable"><table class="table"> |
| <colgroup> |
| <col> |
| <col> |
| <col> |
| </colgroup> |
| <thead><tr> |
| <th> |
| <p> |
| Parameter |
| </p> |
| </th> |
| <th> |
| <p> |
| Description |
| </p> |
| </th> |
| <th> |
| <p> |
| Default |
| </p> |
| </th> |
| </tr></thead> |
| <tbody> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">T</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| The type, <code class="computeroutput"><span class="identifier">T</span></code> |
| for which a custom mapping to a generator should be established. |
| </p> |
| </td> |
| <td> |
| <p> |
| none |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">Enable</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Helper template parameter usable to selectively enable or disable |
| certain specializations of <code class="computeroutput"><span class="identifier">create_generator</span></code> |
| utilizing SFINAE (i.e. <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">enable_if</span></code> |
| or <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">disable_if</span></code>). |
| </p> |
| </td> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="keyword">void</span></code> |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <a name="spirit.advanced.customize.auto.create_generator.notation"></a><h6> |
| <a name="id1201939"></a> |
| <a class="link" href="create_generator.html#spirit.advanced.customize.auto.create_generator.notation">Notation</a> |
| </h6> |
| <div class="variablelist"> |
| <p class="title"><b></b></p> |
| <dl> |
| <dt><span class="term"><code class="computeroutput"><span class="identifier">T</span></code></span></dt> |
| <dd><p> |
| An arbitrary type. |
| </p></dd> |
| </dl> |
| </div> |
| <a name="spirit.advanced.customize.auto.create_generator.expression_semantics"></a><h6> |
| <a name="id1201980"></a> |
| <a class="link" href="create_generator.html#spirit.advanced.customize.auto.create_generator.expression_semantics">Expression |
| Semantics</a> |
| </h6> |
| <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">create_generator</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">type</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Defines the type of the generator expression returned from |
| <code class="computeroutput"><span class="identifier">call</span></code>. |
| </p> |
| </td> |
| </tr> |
| <tr> |
| <td> |
| <p> |
| <code class="computeroutput"><span class="identifier">create_generator</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">call</span><span class="special">()</span></code> |
| </p> |
| </td> |
| <td> |
| <p> |
| Returns a generator expression (usually this is a proto::expression) |
| to be used as the default generator for the given type, <code class="computeroutput"><span class="identifier">T</span></code>. |
| </p> |
| </td> |
| </tr> |
| </tbody> |
| </table></div> |
| <a name="spirit.advanced.customize.auto.create_generator.predefined_specializations"></a><h6> |
| <a name="id1202125"></a> |
| <a class="link" href="create_generator.html#spirit.advanced.customize.auto.create_generator.predefined_specializations">Predefined |
| Specializations</a> |
| </h6> |
| <p> |
| <a href="http://boost-spirit.com" target="_top">Spirit</a> predefines specializations |
| of this customization point for several types. All predefined mappings |
| are listed here: <a class="link" href="../../../karma/reference/auto.html#spirit.karma.reference.auto.additional_requirements">Additional |
| Attribute Requirements for Generators</a>. |
| </p> |
| <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> |
| It is possible to overload the predefined mappings for the listed types |
| by providing your own specialization of the <code class="computeroutput"><span class="identifier">create_generator</span></code> |
| customization point for the type to modify. |
| </p></td></tr> |
| </table></div> |
| <a name="spirit.advanced.customize.auto.create_generator.when_to_implement"></a><h6> |
| <a name="id1202167"></a> |
| <a class="link" href="create_generator.html#spirit.advanced.customize.auto.create_generator.when_to_implement">When |
| to implement</a> |
| </h6> |
| <p> |
| The customization point <code class="computeroutput"><span class="identifier">create_generator</span></code> |
| needs to be implemented for a specific type whenever this type should |
| be usable with the API function <a class="link" href="../../../karma/reference/generate_api/create_generator.html" title="API for Automatic Generator Creation"><code class="computeroutput"><span class="identifier">create_generator</span></code></a> (which includes |
| using the <code class="computeroutput"><span class="identifier">karma</span><span class="special">::</span><span class="identifier">auto_</span></code> generator and the special API |
| functions based on the automatic creation of the matching generator type). |
| </p> |
| <a name="spirit.advanced.customize.auto.create_generator.example"></a><h6> |
| <a name="id1202215"></a> |
| <a class="link" href="create_generator.html#spirit.advanced.customize.auto.create_generator.example">Example</a> |
| </h6> |
| <p> |
| For an example of how to use the customization point <code class="computeroutput"><span class="identifier">create_generator</span></code> |
| please see here: <a class="link" href="../../../karma/reference/auto.html#spirit.karma.reference.auto.example">Example |
| for Using the <code class="computeroutput"><span class="identifier">karma</span><span class="special">::</span><span class="identifier">auto_</span></code> Generator</a>. |
| </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>) |
| </p> |
| </div></td> |
| </tr></table> |
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