1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Sequence Facade</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="Chapter 1. Fusion 2.2"> 8<link rel="up" href="../extension.html" title="Extension"> 9<link rel="prev" href="ext_full.html" title="The Full Extension Mechanism"> 10<link rel="next" href="iterator_facade.html" title="Iterator Facade"> 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="ext_full.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../extension.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="iterator_facade.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h3 class="title"> 27<a name="fusion.extension.sequence_facade"></a><a class="link" href="sequence_facade.html" title="Sequence Facade">Sequence Facade</a> 28</h3></div></div></div> 29<h5> 30<a name="fusion.extension.sequence_facade.h0"></a> 31 <span class="phrase"><a name="fusion.extension.sequence_facade.description"></a></span><a class="link" href="sequence_facade.html#fusion.extension.sequence_facade.description">Description</a> 32 </h5> 33<p> 34 The <a class="link" href="sequence_facade.html" title="Sequence Facade"><code class="computeroutput"><span class="identifier">sequence_facade</span></code></a> 35 template provides an intrusive mechanism for producing a conforming Fusion 36 sequence. 37 </p> 38<h5> 39<a name="fusion.extension.sequence_facade.h1"></a> 40 <span class="phrase"><a name="fusion.extension.sequence_facade.synopsis"></a></span><a class="link" href="sequence_facade.html#fusion.extension.sequence_facade.synopsis">Synopsis</a> 41 </h5> 42<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Derived</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">TravesalTag</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">IsView</span> <span class="special">=</span> <span class="identifier">mpl</span><span class="special">::</span><span class="identifier">false_</span><span class="special">></span> 43<span class="keyword">struct</span> <span class="identifier">sequence_facade</span><span class="special">;</span> 44</pre> 45<h5> 46<a name="fusion.extension.sequence_facade.h2"></a> 47 <span class="phrase"><a name="fusion.extension.sequence_facade.usage"></a></span><a class="link" href="sequence_facade.html#fusion.extension.sequence_facade.usage">Usage</a> 48 </h5> 49<p> 50 The user of <a class="link" href="sequence_facade.html" title="Sequence Facade"><code class="computeroutput"><span class="identifier">sequence_facade</span></code></a> derives his sequence 51 type from a specialization of <a class="link" href="sequence_facade.html" title="Sequence Facade"><code class="computeroutput"><span class="identifier">sequence_facade</span></code></a> and passes the derived 52 sequence type as the first template parameter. The second template parameter 53 should be the traversal category of the sequence being implemented. The 3rd 54 parameter should be set to <code class="computeroutput"><span class="identifier">mpl</span><span class="special">::</span><span class="identifier">true_</span></code> 55 if the sequence is a view. 56 </p> 57<p> 58 The user must implement the key expressions required by their sequence type. 59 </p> 60<div class="table"> 61<a name="fusion.extension.sequence_facade.t0"></a><p class="title"><b>Table 1.106. Parameters</b></p> 62<div class="table-contents"><table class="table" summary="Parameters"> 63<colgroup> 64<col> 65<col> 66</colgroup> 67<thead><tr> 68<th> 69 <p> 70 Name 71 </p> 72 </th> 73<th> 74 <p> 75 Description 76 </p> 77 </th> 78</tr></thead> 79<tbody> 80<tr> 81<td> 82 <p> 83 <code class="computeroutput"><span class="identifier">sequence</span></code>, <code class="computeroutput"><span class="identifier">Seq</span></code> 84 </p> 85 </td> 86<td> 87 <p> 88 A type derived from <a class="link" href="sequence_facade.html" title="Sequence Facade"><code class="computeroutput"><span class="identifier">sequence_facade</span></code></a> 89 </p> 90 </td> 91</tr> 92<tr> 93<td> 94 <p> 95 <code class="computeroutput"><span class="identifier">N</span></code> 96 </p> 97 </td> 98<td> 99 <p> 100 An <a href="http://www.boost.org/libs/mpl/doc/refmanual/integral-constant.html" target="_top">MPL 101 Integral Constant</a> 102 </p> 103 </td> 104</tr> 105</tbody> 106</table></div> 107</div> 108<br class="table-break"><div class="table"> 109<a name="fusion.extension.sequence_facade.t1"></a><p class="title"><b>Table 1.107. Key Expressions</b></p> 110<div class="table-contents"><table class="table" summary="Key Expressions"> 111<colgroup> 112<col> 113<col> 114</colgroup> 115<thead><tr> 116<th> 117 <p> 118 Expression 119 </p> 120 </th> 121<th> 122 <p> 123 Result 124 </p> 125 </th> 126</tr></thead> 127<tbody> 128<tr> 129<td> 130 <p> 131 <code class="computeroutput"><span class="identifier">sequence</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">begin</span><span class="special"><</span><span class="identifier">Seq</span><span class="special">>::</span><span class="identifier">type</span></code> 132 </p> 133 </td> 134<td> 135 <p> 136 The type of an iterator to the beginning of a sequence of type 137 <code class="computeroutput"><span class="identifier">Seq</span></code> 138 </p> 139 </td> 140</tr> 141<tr> 142<td> 143 <p> 144 <code class="computeroutput"><span class="identifier">sequence</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">begin</span><span class="special"><</span><span class="identifier">Seq</span><span class="special">>::</span><span class="identifier">call</span><span class="special">(</span><span class="identifier">seq</span><span class="special">)</span></code> 145 </p> 146 </td> 147<td> 148 <p> 149 An iterator to the beginning of sequence <code class="computeroutput"><span class="identifier">seq</span></code> 150 </p> 151 </td> 152</tr> 153<tr> 154<td> 155 <p> 156 <code class="computeroutput"><span class="identifier">sequence</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">end</span><span class="special"><</span><span class="identifier">Seq</span><span class="special">>::</span><span class="identifier">type</span></code> 157 </p> 158 </td> 159<td> 160 <p> 161 The type of an iterator to the end of a sequence of type <code class="computeroutput"><span class="identifier">Seq</span></code> 162 </p> 163 </td> 164</tr> 165<tr> 166<td> 167 <p> 168 <code class="computeroutput"><span class="identifier">sequence</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">end</span><span class="special"><</span><span class="identifier">Seq</span><span class="special">>::</span><span class="identifier">call</span><span class="special">(</span><span class="identifier">seq</span><span class="special">)</span></code> 169 </p> 170 </td> 171<td> 172 <p> 173 An iterator to the end of sequence <code class="computeroutput"><span class="identifier">seq</span></code> 174 </p> 175 </td> 176</tr> 177<tr> 178<td> 179 <p> 180 <code class="computeroutput"><span class="identifier">sequence</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">size</span><span class="special"><</span><span class="identifier">Seq</span><span class="special">>::</span><span class="identifier">type</span></code> 181 </p> 182 </td> 183<td> 184 <p> 185 The size of a sequence of type <code class="computeroutput"><span class="identifier">Seq</span></code> 186 as an <a href="http://www.boost.org/libs/mpl/doc/refmanual/integral-constant.html" target="_top">MPL 187 Integral Constant</a> 188 </p> 189 </td> 190</tr> 191<tr> 192<td> 193 <p> 194 <code class="computeroutput"><span class="identifier">sequence</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">size</span><span class="special"><</span><span class="identifier">Seq</span><span class="special">>::</span><span class="identifier">call</span><span class="special">(</span><span class="identifier">seq</span><span class="special">)</span></code> 195 </p> 196 </td> 197<td> 198 <p> 199 The size of sequence <code class="computeroutput"><span class="identifier">seq</span></code> 200 </p> 201 </td> 202</tr> 203<tr> 204<td> 205 <p> 206 <code class="computeroutput"><span class="identifier">sequence</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">empty</span><span class="special"><</span><span class="identifier">Seq</span><span class="special">>::</span><span class="identifier">type</span></code> 207 </p> 208 </td> 209<td> 210 <p> 211 Returns <code class="computeroutput"><span class="identifier">mpl</span><span class="special">::</span><span class="identifier">true_</span></code> if <code class="computeroutput"><span class="identifier">Seq</span></code> 212 has zero elements, <code class="computeroutput"><span class="identifier">mpl</span><span class="special">::</span><span class="identifier">false_</span></code> 213 otherwise. 214 </p> 215 </td> 216</tr> 217<tr> 218<td> 219 <p> 220 <code class="computeroutput"><span class="identifier">sequence</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">empty</span><span class="special"><</span><span class="identifier">Seq</span><span class="special">>::</span><span class="identifier">call</span></code> 221 </p> 222 </td> 223<td> 224 <p> 225 Returns a type convertible to <code class="computeroutput"><span class="keyword">bool</span></code> 226 that evaluates to true if the sequence is empty, else, evaluates 227 to false. 228 </p> 229 </td> 230</tr> 231<tr> 232<td> 233 <p> 234 <code class="computeroutput"><span class="identifier">sequence</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">at</span><span class="special"><</span><span class="identifier">Seq</span><span class="special">,</span> <span class="identifier">N</span><span class="special">>::</span><span class="identifier">type</span></code> 235 </p> 236 </td> 237<td> 238 <p> 239 The type of element <code class="computeroutput"><span class="identifier">N</span></code> 240 in a sequence of type <code class="computeroutput"><span class="identifier">Seq</span></code> 241 </p> 242 </td> 243</tr> 244<tr> 245<td> 246 <p> 247 <code class="computeroutput"><span class="identifier">sequence</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">at</span><span class="special"><</span><span class="identifier">Seq</span><span class="special">,</span> <span class="identifier">N</span><span class="special">>::</span><span class="identifier">call</span><span class="special">(</span><span class="identifier">seq</span><span class="special">)</span></code> 248 </p> 249 </td> 250<td> 251 <p> 252 Element <code class="computeroutput"><span class="identifier">N</span></code> in sequence 253 <code class="computeroutput"><span class="identifier">seq</span></code> 254 </p> 255 </td> 256</tr> 257<tr> 258<td> 259 <p> 260 <code class="computeroutput"><span class="identifier">sequence</span><span class="special">::</span><span class="keyword">template</span> <span class="identifier">value_at</span><span class="special"><</span><span class="identifier">Sequence</span><span class="special">,</span> <span class="identifier">N</span><span class="special">>::</span><span class="identifier">type</span></code> 261 </p> 262 </td> 263<td> 264 <p> 265 The type of the <code class="computeroutput"><span class="identifier">N</span></code>th 266 element in a sequence of type <code class="computeroutput"><span class="identifier">Seq</span></code> 267 </p> 268 </td> 269</tr> 270</tbody> 271</table></div> 272</div> 273<br class="table-break"><h5> 274<a name="fusion.extension.sequence_facade.h3"></a> 275 <span class="phrase"><a name="fusion.extension.sequence_facade.include"></a></span><a class="link" href="sequence_facade.html#fusion.extension.sequence_facade.include">Include</a> 276 </h5> 277<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">sequence</span><span class="special">/</span><span class="identifier">sequence_facade</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 278<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">sequence_facade</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 279</pre> 280<h5> 281<a name="fusion.extension.sequence_facade.h4"></a> 282 <span class="phrase"><a name="fusion.extension.sequence_facade.example"></a></span><a class="link" href="sequence_facade.html#fusion.extension.sequence_facade.example">Example</a> 283 </h5> 284<p> 285 A full working example using <a class="link" href="sequence_facade.html" title="Sequence Facade"><code class="computeroutput"><span class="identifier">sequence_facade</span></code></a> is provided in triple.cpp 286 in the extension examples. 287 </p> 288</div> 289<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 290<td align="left"></td> 291<td align="right"><div class="copyright-footer">Copyright © 2001-2006, 2011, 2012 Joel de Guzman, 292 Dan Marsden, Tobias Schwinger<p> 293 Distributed under the Boost Software License, Version 1.0. (See accompanying 294 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>) 295 </p> 296</div></td> 297</tr></table> 298<hr> 299<div class="spirit-nav"> 300<a accesskey="p" href="ext_full.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../extension.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="iterator_facade.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 301</div> 302</body> 303</html> 304
