<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=US-ASCII"> <title>String (string, lit)</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="../string.html" title="String"> <link rel="prev" href="../string.html" title="String"> <link rel="next" href="symbols.html" title="Symbols (symbols)"> </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="../string.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../string.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="symbols.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.qi.reference.string.string"></a><a class="link" href="string.html" title="String (string, lit)"> String (<code class="computeroutput"><span class="identifier">string</span></code>, <code class="computeroutput"><span class="identifier">lit</span></code>)</a> </h5></div></div></div> <a name="spirit.qi.reference.string.string.description"></a><h6> <a name="id990293"></a> <a class="link" href="string.html#spirit.qi.reference.string.string.description">Description</a> </h6> <p> The <code class="computeroutput"><span class="identifier">string</span></code> parser matches a string of characters. The <code class="computeroutput"><span class="identifier">string</span></code> parser is an implicit lexeme: the <code class="computeroutput"><span class="identifier">skip</span></code> parser is not applied in between characters of the string. The <code class="computeroutput"><span class="identifier">string</span></code> parser has an assocaiated <a class="link" href="../basics.html#spirit.qi.reference.basics.character_encoding_namespace">Character Encoding Namespace</a>. This is needed when doing basic operations such as inhibiting case sensitivity. Examples: </p> <pre class="programlisting"><span class="identifier">string</span><span class="special">(</span><span class="string">"Hello"</span><span class="special">)</span> <span class="identifier">string</span><span class="special">(</span><span class="identifier">L</span><span class="string">"Hello"</span><span class="special">)</span> <span class="identifier">string</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span> <span class="comment">// s is a std::string </span></pre> <p> <code class="computeroutput"><span class="identifier">lit</span></code>, like <code class="computeroutput"><span class="identifier">string</span></code>, also matches a string of characters. The main difference is that <code class="computeroutput"><span class="identifier">lit</span></code> does not synthesize an attribute. A plain string like <code class="computeroutput"><span class="string">"hello"</span></code> or a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_string</span></code> is equivalent to a <code class="computeroutput"><span class="identifier">lit</span></code>. Examples: </p> <pre class="programlisting"><span class="string">"Hello"</span> <span class="identifier">lit</span><span class="special">(</span><span class="string">"Hello"</span><span class="special">)</span> <span class="identifier">lit</span><span class="special">(</span><span class="identifier">L</span><span class="string">"Hello"</span><span class="special">)</span> <span class="identifier">lit</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span> <span class="comment">// s is a std::string </span></pre> <a name="spirit.qi.reference.string.string.header"></a><h6> <a name="id990518"></a> <a class="link" href="string.html#spirit.qi.reference.string.string.header">Header</a> </h6> <pre class="programlisting"><span class="comment">// forwards to <boost/spirit/home/qi/string/lit.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_lit</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> </pre> <a name="spirit.qi.reference.string.string.namespace"></a><h6> <a name="id990584"></a> <a class="link" href="string.html#spirit.qi.reference.string.string.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">lit</span> <span class="comment">// alias: boost::spirit::qi::lit</span></code> </p> </td></tr> <tr><td> <p> <code class="computeroutput"><span class="identifier">ns</span><span class="special">::</span><span class="identifier">string</span></code> </p> </td></tr> </tbody> </table></div> <p> In the table above, <code class="computeroutput"><span class="identifier">ns</span></code> represents a <a class="link" href="../basics.html#spirit.qi.reference.basics.character_encoding_namespace">Character Encoding Namespace</a>. </p> <a name="spirit.qi.reference.string.string.model_of"></a><h6> <a name="id990703"></a> <a class="link" href="string.html#spirit.qi.reference.string.string.model_of">Model of</a> </h6> <div class="blockquote"><blockquote class="blockquote"><p> <a class="link" href="../parser_concepts/primitiveparser.html" title="PrimitiveParser"><code class="computeroutput"><span class="identifier">PrimitiveParser</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">s</span></code></span></dt> <dd><p> A <a class="link" href="../basics.html#spirit.qi.reference.basics.string">String</a> or a <a class="link" href="../basics.html#spirit.qi.reference.basics.lazy_argument">Lazy Argument</a> that evaluates to a <a class="link" href="../basics.html#spirit.qi.reference.basics.string">String</a>. </p></dd> <dt><span class="term"><code class="computeroutput"><span class="identifier">ns</span></code></span></dt> <dd><p> A <a class="link" href="../basics.html#spirit.qi.reference.basics.character_encoding_namespace">Character Encoding Namespace</a>. </p></dd> </dl> </div> <a name="spirit.qi.reference.string.string.expression_semantics"></a><h6> <a name="id990798"></a> <a class="link" href="string.html#spirit.qi.reference.string.string.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/primitiveparser.html" title="PrimitiveParser"><code class="computeroutput"><span class="identifier">PrimitiveParser</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">s</span></code> </p> </td> <td> <p> Create string parser from a string, <code class="computeroutput"><span class="identifier">s</span></code>. </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">lit</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code> </p> </td> <td> <p> Create a string parser from a string, <code class="computeroutput"><span class="identifier">s</span></code>. </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">ns</span><span class="special">::</span><span class="identifier">string</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code> </p> </td> <td> <p> Create a string parser with <code class="computeroutput"><span class="identifier">ns</span></code> encoding from a string, <code class="computeroutput"><span class="identifier">s</span></code>. </p> </td> </tr> </tbody> </table></div> <a name="spirit.qi.reference.string.string.attributes"></a><h6> <a name="id990995"></a> <a class="link" href="string.html#spirit.qi.reference.string.string.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">s</span></code> </p> </td> <td> <p> <code class="computeroutput"><span class="identifier">unused</span></code> </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">lit</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code> </p> </td> <td> <p> <code class="computeroutput"><span class="identifier">unused</span></code> </p> </td> </tr> <tr> <td> <p> <code class="computeroutput"><span class="identifier">ns</span><span class="special">::</span><span class="identifier">string</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code> </p> </td> <td> <p> <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_string</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span></code> where <code class="computeroutput"><span class="identifier">T</span></code> is the underlying character type of <code class="computeroutput"><span class="identifier">s</span></code>. </p> </td> </tr> </tbody> </table></div> <a name="spirit.qi.reference.string.string.complexity"></a><h6> <a name="id991202"></a> <a class="link" href="string.html#spirit.qi.reference.string.string.complexity">Complexity</a> </h6> <div class="blockquote"><blockquote class="blockquote"><p> O(N) </p></blockquote></div> <p> where <code class="computeroutput"><span class="identifier">N</span></code> is the number of characters in the string to be parsed. </p> <a name="spirit.qi.reference.string.string.example"></a><h6> <a name="id991233"></a> <a class="link" href="string.html#spirit.qi.reference.string.string.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">lit</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">string</span><span class="special">;</span> </pre> <p> </p> <p> Basic literals: </p> <p> </p> <pre class="programlisting"><span class="identifier">test_parser</span><span class="special">(</span><span class="string">"boost"</span><span class="special">,</span> <span class="string">"boost"</span><span class="special">);</span> <span class="comment">// plain literal </span><span class="identifier">test_parser</span><span class="special">(</span><span class="string">"boost"</span><span class="special">,</span> <span class="identifier">lit</span><span class="special">(</span><span class="string">"boost"</span><span class="special">));</span> <span class="comment">// explicit literal </span><span class="identifier">test_parser</span><span class="special">(</span><span class="string">"boost"</span><span class="special">,</span> <span class="identifier">string</span><span class="special">(</span><span class="string">"boost"</span><span class="special">));</span> <span class="comment">// ascii::string </span></pre> <p> </p> <p> From a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span></code> </p> <p> </p> <pre class="programlisting"><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">s</span><span class="special">(</span><span class="string">"boost"</span><span class="special">);</span> <span class="identifier">test_parser</span><span class="special">(</span><span class="string">"boost"</span><span class="special">,</span> <span class="identifier">s</span><span class="special">);</span> <span class="comment">// direct </span><span class="identifier">test_parser</span><span class="special">(</span><span class="string">"boost"</span><span class="special">,</span> <span class="identifier">lit</span><span class="special">(</span><span class="identifier">s</span><span class="special">));</span> <span class="comment">// explicit </span><span class="identifier">test_parser</span><span class="special">(</span><span class="string">"boost"</span><span class="special">,</span> <span class="identifier">string</span><span class="special">(</span><span class="identifier">s</span><span class="special">));</span> <span class="comment">// ascii::string </span></pre> <p> </p> <p> Lazy strings using <a href="../../../../../../phoenix/doc/html/index.html" target="_top">Phoenix</a> </p> <p> </p> <pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">phx</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">phoenix</span><span class="special">;</span> <span class="identifier">test_parser</span><span class="special">(</span><span class="string">"boost"</span><span class="special">,</span> <span class="identifier">phx</span><span class="special">::</span><span class="identifier">val</span><span class="special">(</span><span class="string">"boost"</span><span class="special">));</span> <span class="comment">// direct </span><span class="identifier">test_parser</span><span class="special">(</span><span class="string">"boost"</span><span class="special">,</span> <span class="identifier">lit</span><span class="special">(</span><span class="identifier">phx</span><span class="special">::</span><span class="identifier">val</span><span class="special">(</span><span class="string">"boost"</span><span class="special">)));</span> <span class="comment">// explicit </span><span class="identifier">test_parser</span><span class="special">(</span><span class="string">"boost"</span><span class="special">,</span> <span class="identifier">string</span><span class="special">(</span><span class="identifier">phx</span><span class="special">::</span><span class="identifier">val</span><span class="special">(</span><span class="string">"boost"</span><span class="special">)));</span> <span class="comment">// ascii::string </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="../string.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../string.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="symbols.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> </div> </body> </html>