<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> <title>Grammar</title> <link rel="stylesheet" href="../../../../../../../../doc/src/boostbook.css" type="text/css"> <meta name="generator" content="DocBook XSL Stylesheets V1.75.0"> <link rel="home" href="../../../../index.html" title="Spirit 2.4"> <link rel="up" href="../nonterminal.html" title="Nonterminal"> <link rel="prev" href="rule.html" title="Rule"> <link rel="next" href="../numeric.html" title="Numeric"> </head> <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> <table cellpadding="2" width="100%"><tr> <td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../../boost.png"></td> <td align="center"><a href="../../../../../../../../index.html">Home</a></td> <td align="center"><a href="../../../../../../../../libs/libraries.htm">Libraries</a></td> <td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> <td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> <td align="center"><a href="../../../../../../../../more/index.htm">More</a></td> </tr></table> <hr> <div class="spirit-nav"> <a accesskey="p" href="rule.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../nonterminal.html"><img src="../../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../../index.html"><img src="../../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="../numeric.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> </div> <div class="section"> <div class="titlepage"><div><div><h5 class="title"> <a name="spirit.karma.reference.nonterminal.grammar"></a><a class="link" href="grammar.html" title="Grammar">Grammar</a> </h5></div></div></div> <a name="spirit.karma.reference.nonterminal.grammar.description"></a><h6> <a name="id1103633"></a> <a class="link" href="grammar.html#spirit.karma.reference.nonterminal.grammar.description">Description</a> </h6> <p> The grammar encapsulates a set of <a class="link" href="rule.html" title="Rule">rules</a> (as well as primitive generators (<a class="link" href="../generator_concepts/primitivegenerator.html" title="PrimitiveGenerator"><code class="computeroutput"><span class="identifier">PrimitiveGenerator</span></code></a>) and sub-grammars). The grammar is the main mechanism for modularization and composition. Grammars can be composed to form more complex grammars. </p> <a name="spirit.karma.reference.nonterminal.grammar.header"></a><h6> <a name="id1103666"></a> <a class="link" href="grammar.html#spirit.karma.reference.nonterminal.grammar.header">Header</a> </h6> <pre class="programlisting"><span class="comment">// forwards to <boost/spirit/home/karma/nonterminal/grammar.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_grammar</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.karma.reference.nonterminal.grammar.namespace"></a><h6> <a name="id1103741"></a> <a class="link" href="grammar.html#spirit.karma.reference.nonterminal.grammar.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">karma</span><span class="special">::</span><span class="identifier">grammar</span></code> </p> </td></tr></tbody> </table></div> <a name="spirit.karma.reference.nonterminal.grammar.synopsis"></a><h6> <a name="id1103821"></a> <a class="link" href="grammar.html#spirit.karma.reference.nonterminal.grammar.synopsis">Synopsis</a> </h6> <pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">OutputIterator</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">A1</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">A2</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">A3</span><span class="special">></span> <span class="keyword">struct</span> <span class="identifier">grammar</span><span class="special">;</span> </pre> <a name="spirit.karma.reference.nonterminal.grammar.template_parameters"></a><h6> <a name="id1103915"></a> <a class="link" href="grammar.html#spirit.karma.reference.nonterminal.grammar.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">OutputIterator</span></code> </p> </td> <td> <p> The underlying output iterator type that the rule is expected to work on. </p> </td> <td> <p> none </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">A1</span></code>, <code class="computeroutput"><span class="identifier">A2</span></code>, <code class="computeroutput"><span class="identifier">A3</span></code> </p> </td> <td> <p> Either <code class="computeroutput"><span class="identifier">Signature</span></code>, <code class="computeroutput"><span class="identifier">Delimiter</span></code> or <code class="computeroutput"><span class="identifier">Locals</span></code> in any order. See table below. </p> </td> <td> <p> See table below. </p> </td> </tr> </tbody> </table></div> <p> Here is more information about the template parameters: </p> <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">Signature</span></code> </p> </td> <td> <p> Specifies the grammar's synthesized (return value) and inherited attributes (arguments). More on this here: <a class="link" href="../generator_concepts/nonterminal.html" title="Nonterminal"><code class="computeroutput"><span class="identifier">Nonterminal</span></code></a>. </p> </td> <td> <p> <code class="computeroutput"><span class="identifier">unused_type</span></code>. When <code class="computeroutput"><span class="identifier">Signature</span></code> defaults to <code class="computeroutput"><span class="identifier">unused_type</span></code>, the effect is the same as specifying a signature of <code class="computeroutput"><span class="keyword">void</span><span class="special">()</span></code> which is also equivalent to <code class="computeroutput"><span class="identifier">unused_type</span><span class="special">()</span></code> </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">Delimiter</span></code> </p> </td> <td> <p> Specifies the grammar's delimiter generator. Specify this if you want the grammer to delimit the generated output. </p> </td> <td> <p> <code class="computeroutput"><span class="identifier">unused_type</span></code> </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">Locals</span></code> </p> </td> <td> <p> Specifies the grammar's local variables. See <a class="link" href="../generator_concepts/nonterminal.html" title="Nonterminal"><code class="computeroutput"><span class="identifier">Nonterminal</span></code></a>. </p> </td> <td> <p> <code class="computeroutput"><span class="identifier">unused_type</span></code> </p> </td> </tr> </tbody> </table></div> <a name="spirit.karma.reference.nonterminal.grammar.model_of"></a><h6> <a name="id1104294"></a> <a class="link" href="grammar.html#spirit.karma.reference.nonterminal.grammar.model_of">Model of</a> </h6> <div class="blockquote"><blockquote class="blockquote"><p> <a class="link" href="../generator_concepts/nonterminal.html" title="Nonterminal"><code class="computeroutput"><span class="identifier">Nonterminal</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">g</span></code></span></dt> <dd><p> A grammar </p></dd> </dl> </div> <a name="spirit.karma.reference.nonterminal.grammar.expression_semantics"></a><h6> <a name="id1104353"></a> <a class="link" href="grammar.html#spirit.karma.reference.nonterminal.grammar.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/nonterminal.html" title="Nonterminal"><code class="computeroutput"><span class="identifier">Nonterminal</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> </p> <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">OutputIterator</span><span class="special">></span> <span class="keyword">struct</span> <span class="identifier">my_grammar</span> <span class="special">:</span> <span class="identifier">grammar</span><span class="special"><</span><span class="identifier">OutputIterator</span><span class="special">,</span> <span class="identifier">A1</span><span class="special">,</span> <span class="identifier">A2</span><span class="special">,</span> <span class="identifier">A3</span><span class="special">></span> <span class="special">{</span> <span class="identifier">my_grammar</span><span class="special">()</span> <span class="special">:</span> <span class="identifier">my_grammar</span><span class="special">::</span><span class="identifier">base_type</span><span class="special">(</span><span class="identifier">start</span><span class="special">,</span> <span class="identifier">name</span><span class="special">)</span> <span class="special">{</span> <span class="comment">// Rule definitions </span> <span class="identifier">start</span> <span class="special">=</span> <span class="comment">/* ... */</span><span class="special">;</span> <span class="special">}</span> <span class="identifier">rule</span><span class="special"><</span><span class="identifier">OutputIterator</span><span class="special">,</span> <span class="identifier">A1</span><span class="special">,</span> <span class="identifier">A2</span><span class="special">,</span> <span class="identifier">A3</span><span class="special">></span> <span class="identifier">start</span><span class="special">;</span> <span class="comment">// more rule declarations... </span><span class="special">};</span> </pre> <p> </p> </td> <td> <p> Grammar definition. <code class="computeroutput"><span class="identifier">name</span></code> is an optional string that gives the grammar its name, useful for debugging. </p> </td> </tr></tbody> </table></div> <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 template parameters of a grammar and its start rule (the rule passed to the grammar's base class constructor) must match, otherwise you will see compilation errors. </p></td></tr> </table></div> <a name="spirit.karma.reference.nonterminal.grammar.attributes"></a><h6> <a name="id1104668"></a> <a class="link" href="grammar.html#spirit.karma.reference.nonterminal.grammar.attributes">Attributes</a> </h6> <div class="blockquote"><blockquote class="blockquote"><p> The generator attribute of the grammar is <code class="computeroutput"><span class="identifier">RT</span></code>, its consumed attribute. See <a class="link" href="../generator_concepts/nonterminal.html#spirit.karma.reference.generator_concepts.nonterminal.attributes"><code class="computeroutput"><span class="identifier">Attribute</span></code></a> </p></blockquote></div> <a name="spirit.karma.reference.nonterminal.grammar.complexity"></a><h6> <a name="id1104707"></a> <a class="link" href="grammar.html#spirit.karma.reference.nonterminal.grammar.complexity">Complexity</a> </h6> <div class="blockquote"><blockquote class="blockquote"><p> The complexity is defined by the complexity of the its definition. </p></blockquote></div> <a name="spirit.karma.reference.nonterminal.grammar.example"></a><h6> <a name="id1104727"></a> <a class="link" href="grammar.html#spirit.karma.reference.nonterminal.grammar.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 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">ascii</span><span class="special">::</span><span class="identifier">space_type</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">ascii</span><span class="special">::</span><span class="identifier">space</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">int_</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">grammar</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">rule</span><span class="special">;</span> </pre> <p> </p> <p> Basic grammar usage: </p> <p> </p> <pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">num_list</span> <span class="special">:</span> <span class="identifier">grammar</span><span class="special"><</span><span class="identifier">output_iterator_type</span><span class="special">,</span> <span class="identifier">space_type</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="keyword">int</span><span class="special">>()></span> <span class="special">{</span> <span class="identifier">num_list</span><span class="special">()</span> <span class="special">:</span> <span class="identifier">base_type</span><span class="special">(</span><span class="identifier">start</span><span class="special">)</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">int_</span><span class="special">;</span> <span class="identifier">num</span> <span class="special">=</span> <span class="identifier">int_</span><span class="special">;</span> <span class="identifier">start</span> <span class="special">=</span> <span class="identifier">num</span> <span class="special"><<</span> <span class="special">*(</span><span class="char">','</span> <span class="special"><<</span> <span class="identifier">num</span><span class="special">);</span> <span class="special">}</span> <span class="identifier">rule</span><span class="special"><</span><span class="identifier">output_iterator_type</span><span class="special">,</span> <span class="identifier">space_type</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="keyword">int</span><span class="special">>()></span> <span class="identifier">start</span><span class="special">;</span> <span class="identifier">rule</span><span class="special"><</span><span class="identifier">output_iterator_type</span><span class="special">,</span> <span class="identifier">space_type</span><span class="special">,</span> <span class="keyword">int</span><span class="special">()></span> <span class="identifier">num</span><span class="special">;</span> <span class="special">};</span> </pre> <p> </p> <p> How to use the example grammar: </p> <p> </p> <pre class="programlisting"><span class="identifier">num_list</span> <span class="identifier">nlist</span><span class="special">;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="identifier">v</span><span class="special">;</span> <span class="identifier">v</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="number">123</span><span class="special">);</span> <span class="identifier">v</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="number">456</span><span class="special">);</span> <span class="identifier">v</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="number">789</span><span class="special">);</span> <span class="identifier">test_generator_attr_delim</span><span class="special">(</span><span class="string">"123 , 456 , 789"</span><span class="special">,</span> <span class="identifier">nlist</span><span class="special">,</span> <span class="identifier">space</span><span class="special">,</span> <span class="identifier">v</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>) </p> </div></td> </tr></table> <hr> <div class="spirit-nav"> <a accesskey="p" href="rule.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../nonterminal.html"><img src="../../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../../index.html"><img src="../../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="../numeric.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> </div> </body> </html>