1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Generator Operators</title> 5<link rel="stylesheet" href="../../../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../../index.html" title="Spirit 2.5.8"> 8<link rel="up" href="../reference.html" title="Reference"> 9<link rel="prev" href="numeric/boolean.html" title="Boolean Generators (bool_)"> 10<link rel="next" href="operator/sequence.html" title="Sequence Generator (a << b)"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="numeric/boolean.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../reference.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="operator/sequence.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h4 class="title"> 27<a name="spirit.karma.reference.operator"></a><a class="link" href="operator.html" title="Generator Operators">Generator Operators</a> 28</h4></div></div></div> 29<div class="toc"><dl class="toc"> 30<dt><span class="section"><a href="operator/sequence.html">Sequence 31 Generator (<code class="computeroutput"><span class="identifier">a</span> <span class="special"><<</span> 32 <span class="identifier">b</span></code>)</a></span></dt> 33<dt><span class="section"><a href="operator/alternative.html">Alternative 34 Generator (<code class="computeroutput"><span class="identifier">a</span> <span class="special">|</span> 35 <span class="identifier">b</span></code>)</a></span></dt> 36<dt><span class="section"><a href="operator/kleene.html">Kleene Star 37 Generator (<code class="computeroutput"><span class="special">*</span><span class="identifier">a</span></code>)</a></span></dt> 38<dt><span class="section"><a href="operator/plus.html">Plus Generator 39 (<code class="computeroutput"><span class="special">+</span><span class="identifier">a</span></code>)</a></span></dt> 40<dt><span class="section"><a href="operator/list.html">List Generator 41 (<code class="computeroutput"><span class="identifier">a</span> <span class="special">%</span> 42 <span class="identifier">b</span></code>)</a></span></dt> 43<dt><span class="section"><a href="operator/optional.html">Optional 44 Generator (<code class="computeroutput"><span class="special">-</span><span class="identifier">a</span></code>)</a></span></dt> 45<dt><span class="section"><a href="operator/and_predicate.html">And-Predicate 46 Generator (<code class="computeroutput"><span class="special">&</span><span class="identifier">a</span></code>)</a></span></dt> 47<dt><span class="section"><a href="operator/not_predicate.html">Not-Predicate 48 Generator (<code class="computeroutput"><span class="special">!</span><span class="identifier">a</span></code>)</a></span></dt> 49</dl></div> 50<p> 51 Operators are used as a means for object composition and embedding. Simple 52 generators may be composed to form composites through operator overloading, 53 crafted to approximate the syntax of <a class="link" href="../../abstracts/parsing_expression_grammar.html" title="Parsing Expression Grammar">Parsing 54 Expression Grammar</a> (PEG). An expression such as: 55 </p> 56<pre class="programlisting"><span class="identifier">a</span> <span class="special">|</span> <span class="identifier">b</span> 57</pre> 58<p> 59 yields a new generator type which is a composite of its operands, <code class="computeroutput"><span class="identifier">a</span></code> and <code class="computeroutput"><span class="identifier">b</span></code>. 60 </p> 61<p> 62 This module includes different generators which get instantiated if one 63 of the overloaded operators is used with more primitive generator constructs. 64 It includes sequences (<code class="computeroutput"><span class="identifier">a</span> <span class="special"><<</span> <span class="identifier">b</span></code>), 65 alternatives (<code class="computeroutput"><span class="identifier">a</span> <span class="special">|</span> 66 <span class="identifier">b</span></code>), Kleene star (unary <code class="computeroutput"><span class="special">*</span></code>), plus (unary <code class="computeroutput"><span class="special">+</span></code>), 67 optional (unary <code class="computeroutput"><span class="special">-</span></code>), lists 68 (<code class="computeroutput"><span class="identifier">a</span> <span class="special">%</span> 69 <span class="identifier">b</span></code>), and the two predicates, the 70 <span class="emphasis"><em>and</em></span> predicate (unary <code class="computeroutput"><span class="special">&</span></code>) 71 and the <span class="emphasis"><em>not</em></span> predicate (unary <code class="computeroutput"><span class="special">!</span></code>). 72 </p> 73<h6> 74<a name="spirit.karma.reference.operator.h0"></a> 75 <span class="phrase"><a name="spirit.karma.reference.operator.module_header"></a></span><a class="link" href="operator.html#spirit.karma.reference.operator.module_header">Module 76 Header</a> 77 </h6> 78<pre class="programlisting"><span class="comment">// forwards to <boost/spirit/home/karma/operator.hpp></span> 79<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_operator</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 80</pre> 81<p> 82 Also, see <a class="link" href="../../structure/include.html" title="Include">Include Structure</a>. 83 </p> 84</div> 85<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 86<td align="left"></td> 87<td align="right"><div class="copyright-footer">Copyright © 2001-2011 Joel de Guzman, Hartmut Kaiser<p> 88 Distributed under the Boost Software License, Version 1.0. (See accompanying 89 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>) 90 </p> 91</div></td> 92</tr></table> 93<hr> 94<div class="spirit-nav"> 95<a accesskey="p" href="numeric/boolean.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../reference.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="operator/sequence.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 96</div> 97</body> 98</html> 99
