1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Generator</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="../generator_concepts.html" title="Generator Concepts"> 9<link rel="prev" href="../generator_concepts.html" title="Generator Concepts"> 10<link rel="next" href="primitivegenerator.html" title="PrimitiveGenerator"> 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="../generator_concepts.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../generator_concepts.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="primitivegenerator.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h5 class="title"> 27<a name="spirit.karma.reference.generator_concepts.generator"></a><a class="link" href="generator.html" title="Generator">Generator</a> 28</h5></div></div></div> 29<h6> 30<a name="spirit.karma.reference.generator_concepts.generator.h0"></a> 31 <span class="phrase"><a name="spirit.karma.reference.generator_concepts.generator.description"></a></span><a class="link" href="generator.html#spirit.karma.reference.generator_concepts.generator.description">Description</a> 32 </h6> 33<p> 34 The <span class="emphasis"><em>Generator</em></span> is the most fundamental concept. A 35 Generator has a member function, <code class="computeroutput"><span class="identifier">generate</span></code>, 36 that accepts an <code class="computeroutput"><span class="identifier">OutputIterator</span></code> 37 and returns bool as its result. The iterator receives the data being 38 generated. The Generator's <code class="computeroutput"><span class="identifier">generate</span></code> 39 member function returns <code class="computeroutput"><span class="keyword">true</span></code> 40 if the generator succeeds. Each Generator can represent a specific pattern 41 or algorithm, or it can be a more complex generator formed as a composition 42 of other Generators. 43 </p> 44<div class="variablelist"> 45<p class="title"><b>Notation</b></p> 46<dl class="variablelist"> 47<dt><span class="term"><code class="computeroutput"><span class="identifier">g</span></code></span></dt> 48<dd><p> 49 A <code class="computeroutput"><span class="identifier">Generator</span></code>. 50 </p></dd> 51<dt><span class="term"><code class="computeroutput"><span class="identifier">G</span></code></span></dt> 52<dd><p> 53 A <code class="computeroutput"><span class="identifier">Generator</span></code> type. 54 </p></dd> 55<dt><span class="term"><code class="computeroutput"><span class="identifier">OutIter</span></code></span></dt> 56<dd><p> 57 An <code class="computeroutput"><span class="identifier">OutputIterator</span></code> 58 type. 59 </p></dd> 60<dt><span class="term"><code class="computeroutput"><span class="identifier">sink</span></code></span></dt> 61<dd><p> 62 An <code class="computeroutput"><span class="identifier">OutputIterator</span></code> 63 instance. 64 </p></dd> 65<dt><span class="term"><code class="computeroutput"><span class="identifier">Context</span></code></span></dt> 66<dd><p> 67 The generator's Context type. 68 </p></dd> 69<dt><span class="term"><code class="computeroutput"><span class="identifier">context</span></code></span></dt> 70<dd><p> 71 The generator's Context, or <code class="computeroutput"><span class="identifier">unused</span></code>. 72 </p></dd> 73<dt><span class="term"><code class="computeroutput"><span class="identifier">delimit</span></code></span></dt> 74<dd><p> 75 A delimiter Generator, or <code class="computeroutput"><span class="identifier">unused</span></code>. 76 </p></dd> 77<dt><span class="term"><code class="computeroutput"><span class="identifier">attrib</span></code></span></dt> 78<dd><p> 79 A Compatible Attributes, or <code class="computeroutput"><span class="identifier">unused</span></code>. 80 </p></dd> 81</dl> 82</div> 83<h6> 84<a name="spirit.karma.reference.generator_concepts.generator.h1"></a> 85 <span class="phrase"><a name="spirit.karma.reference.generator_concepts.generator.valid_expressions"></a></span><a class="link" href="generator.html#spirit.karma.reference.generator_concepts.generator.valid_expressions">Valid 86 Expressions</a> 87 </h6> 88<p> 89 In the expressions below, the behavior of the generator, <code class="computeroutput"><span class="identifier">g</span></code>, as well as how <code class="computeroutput"><span class="identifier">delimit</span></code> 90 and <code class="computeroutput"><span class="identifier">attrib</span></code> are handled 91 by <code class="computeroutput"><span class="identifier">g</span></code>, are left unspecified 92 in the base <code class="computeroutput"><span class="identifier">Generator</span></code> 93 concept. These are specified in subsequent, more refined concepts and 94 by the actual models thereof. 95 </p> 96<p> 97 For any Generator the following expressions must be valid: 98 </p> 99<div class="informaltable"><table class="table"> 100<colgroup> 101<col> 102<col> 103<col> 104</colgroup> 105<thead><tr> 106<th> 107 <p> 108 Expression 109 </p> 110 </th> 111<th> 112 <p> 113 Semantics 114 </p> 115 </th> 116<th> 117 <p> 118 Return type 119 </p> 120 </th> 121</tr></thead> 122<tbody> 123<tr> 124<td> 125 <p> 126</p> 127<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="identifier">g</span><span class="special">.</span><span class="identifier">generate</span><span class="special">(</span><span class="identifier">sink</span><span class="special">,</span> <span class="identifier">context</span><span class="special">,</span> <span class="identifier">delimit</span><span class="special">,</span> <span class="identifier">attrib</span><span class="special">)</span></pre> 128<p> 129 </p> 130 </td> 131<td> 132 <p> 133 Generate the output sequence by inserting the generated characters/tokens 134 into <code class="computeroutput"><span class="identifier">sink</span></code>. 135 Use the <code class="computeroutput"><span class="identifier">delimit</span></code> 136 generator for delimiting. Return <code class="computeroutput"><span class="keyword">true</span></code> 137 if successful, otherwise return <code class="computeroutput"><span class="keyword">false</span></code>. 138 </p> 139 </td> 140<td> 141 <p> 142 <code class="computeroutput"><span class="keyword">bool</span></code> 143 </p> 144 </td> 145</tr> 146<tr> 147<td> 148 <p> 149 <code class="computeroutput"><span class="identifier">g</span><span class="special">.</span><span class="identifier">what</span><span class="special">(</span><span class="identifier">context</span><span class="special">)</span></code> 150 </p> 151 </td> 152<td> 153 <p> 154 Get information about a Generator. 155 </p> 156 </td> 157<td> 158 <p> 159 <code class="computeroutput"><span class="identifier">info</span></code> 160 </p> 161 </td> 162</tr> 163</tbody> 164</table></div> 165<h6> 166<a name="spirit.karma.reference.generator_concepts.generator.h2"></a> 167 <span class="phrase"><a name="spirit.karma.reference.generator_concepts.generator.type_expressions"></a></span><a class="link" href="generator.html#spirit.karma.reference.generator_concepts.generator.type_expressions">Type 168 Expressions</a> 169 </h6> 170<div class="informaltable"><table class="table"> 171<colgroup> 172<col> 173<col> 174</colgroup> 175<thead><tr> 176<th> 177 <p> 178 Expression 179 </p> 180 </th> 181<th> 182 <p> 183 Description 184 </p> 185 </th> 186</tr></thead> 187<tbody> 188<tr> 189<td> 190 <p> 191 <code class="computeroutput"><span class="identifier">G</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">attribute</span><span class="special"><</span><span class="identifier">Context</span><span class="special">>::</span><span class="identifier">type</span></code> 192 </p> 193 </td> 194<td> 195 <p> 196 The Generator's attribute. 197 </p> 198 </td> 199</tr> 200<tr> 201<td> 202 <p> 203 <code class="computeroutput"><span class="identifier">traits</span><span class="special">::</span><span class="identifier">is_generator</span><span class="special"><</span><span class="identifier">G</span><span class="special">>::</span><span class="identifier">type</span></code> 204 </p> 205 </td> 206<td> 207 <p> 208 Metafunction that evaluates to <code class="computeroutput"><span class="identifier">mpl</span><span class="special">::</span><span class="identifier">true_</span></code> 209 if a certain type, <code class="computeroutput"><span class="identifier">G</span></code> 210 is a Generator, <code class="computeroutput"><span class="identifier">mpl</span><span class="special">::</span><span class="identifier">false_</span></code> 211 otherwise (See <a href="../../../../../../../../libs/mpl/doc/refmanual/integral-constant.html" target="_top">MPL 212 Boolean Constant</a>). 213 </p> 214 </td> 215</tr> 216<tr> 217<td> 218 <p> 219 <code class="computeroutput"><span class="identifier">G</span><span class="special">::</span><span class="identifier">properties</span></code> 220 </p> 221 </td> 222<td> 223 <p> 224 An <code class="computeroutput"><span class="identifier">mpl</span><span class="special">::</span><span class="identifier">int_</span></code> (See <a href="../../../../../../../../libs/mpl/doc/refmanual/integral-constant.html" target="_top">MPL 225 Integral Constant</a>) holding a value from the <code class="computeroutput"><span class="identifier">karma</span><span class="special">::</span><span class="identifier">generator_properties</span></code> enumeration. 226 The default value is <code class="computeroutput"><span class="identifier">generator_properties</span><span class="special">::</span><span class="identifier">no_properties</span></code> 227 </p> 228 </td> 229</tr> 230</tbody> 231</table></div> 232<h6> 233<a name="spirit.karma.reference.generator_concepts.generator.h3"></a> 234 <span class="phrase"><a name="spirit.karma.reference.generator_concepts.generator.postcondition"></a></span><a class="link" href="generator.html#spirit.karma.reference.generator_concepts.generator.postcondition">Postcondition</a> 235 </h6> 236<p> 237 Upon return from <code class="computeroutput"><span class="identifier">g</span><span class="special">.</span><span class="identifier">generate</span></code> the following post conditions 238 should hold: 239 </p> 240<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 241<li class="listitem"> 242 On successful generation, <code class="computeroutput"><span class="identifier">sink</span></code> 243 receives the generated characters/tokens sequence. 244 </li> 245<li class="listitem"> 246 No pre-delimits: <code class="computeroutput"><span class="identifier">delimit</span></code> 247 characters/tokens will not be emitted in front of any other output. 248 </li> 249<li class="listitem"> 250 The attribute <code class="computeroutput"><span class="identifier">attrib</span></code> 251 has not been modified. 252 </li> 253</ul></div> 254<h6> 255<a name="spirit.karma.reference.generator_concepts.generator.h4"></a> 256 <span class="phrase"><a name="spirit.karma.reference.generator_concepts.generator.models"></a></span><a class="link" href="generator.html#spirit.karma.reference.generator_concepts.generator.models">Models</a> 257 </h6> 258<p> 259 All generators in <span class="emphasis"><em>Spirit.Karma</em></span> are models of the 260 <span class="emphasis"><em>Generator</em></span> concept. 261 </p> 262</div> 263<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 264<td align="left"></td> 265<td align="right"><div class="copyright-footer">Copyright © 2001-2011 Joel de Guzman, Hartmut Kaiser<p> 266 Distributed under the Boost Software License, Version 1.0. (See accompanying 267 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>) 268 </p> 269</div></td> 270</tr></table> 271<hr> 272<div class="spirit-nav"> 273<a accesskey="p" href="../generator_concepts.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../generator_concepts.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="primitivegenerator.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 274</div> 275</body> 276</html> 277
