1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>is_sequence</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="../support.html" title="Support"> 9<link rel="prev" href="../support.html" title="Support"> 10<link rel="next" href="is_view.html" title="is_view"> 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="../support.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../support.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="is_view.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.support.is_sequence"></a><a class="link" href="is_sequence.html" title="is_sequence">is_sequence</a> 28</h3></div></div></div> 29<h5> 30<a name="fusion.support.is_sequence.h0"></a> 31 <span class="phrase"><a name="fusion.support.is_sequence.description"></a></span><a class="link" href="is_sequence.html#fusion.support.is_sequence.description">Description</a> 32 </h5> 33<p> 34 Metafunction that evaluates to <code class="computeroutput"><span class="identifier">mpl</span><span class="special">::</span><span class="identifier">true_</span></code> 35 if a certain type <code class="computeroutput"><span class="identifier">T</span></code> is a 36 conforming Fusion <a class="link" href="../sequence.html" title="Sequence">Sequence</a>, <code class="computeroutput"><span class="identifier">mpl</span><span class="special">::</span><span class="identifier">false_</span></code> 37 otherwise. This may be specialized to accommodate clients which provide Fusion 38 conforming sequences. 39 </p> 40<h5> 41<a name="fusion.support.is_sequence.h1"></a> 42 <span class="phrase"><a name="fusion.support.is_sequence.synopsis"></a></span><a class="link" href="is_sequence.html#fusion.support.is_sequence.synopsis">Synopsis</a> 43 </h5> 44<pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">traits</span> 45<span class="special">{</span> 46 <span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">></span> 47 <span class="keyword">struct</span> <span class="identifier">is_sequence</span> 48 <span class="special">{</span> 49 <span class="keyword">typedef</span> <span class="emphasis"><em>unspecified</em></span> <span class="identifier">type</span><span class="special">;</span> 50 <span class="special">};</span> 51<span class="special">}</span> 52</pre> 53<h5> 54<a name="fusion.support.is_sequence.h2"></a> 55 <span class="phrase"><a name="fusion.support.is_sequence.parameters"></a></span><a class="link" href="is_sequence.html#fusion.support.is_sequence.parameters">Parameters</a> 56 </h5> 57<div class="informaltable"><table class="table"> 58<colgroup> 59<col> 60<col> 61<col> 62</colgroup> 63<thead><tr> 64<th> 65 <p> 66 Parameter 67 </p> 68 </th> 69<th> 70 <p> 71 Requirement 72 </p> 73 </th> 74<th> 75 <p> 76 Description 77 </p> 78 </th> 79</tr></thead> 80<tbody><tr> 81<td> 82 <p> 83 <code class="computeroutput"><span class="identifier">T</span></code> 84 </p> 85 </td> 86<td> 87 <p> 88 Any type 89 </p> 90 </td> 91<td> 92 <p> 93 The type to query. 94 </p> 95 </td> 96</tr></tbody> 97</table></div> 98<h5> 99<a name="fusion.support.is_sequence.h3"></a> 100 <span class="phrase"><a name="fusion.support.is_sequence.expression_semantics"></a></span><a class="link" href="is_sequence.html#fusion.support.is_sequence.expression_semantics">Expression 101 Semantics</a> 102 </h5> 103<pre class="programlisting"><span class="keyword">typedef</span> <span class="identifier">traits</span><span class="special">::</span><span class="identifier">is_sequence</span><span class="special"><</span><span class="identifier">T</span><span class="special">>::</span><span class="identifier">type</span> <span class="identifier">c</span><span class="special">;</span> 104</pre> 105<p> 106 <span class="bold"><strong>Return type</strong></span>: An <a href="http://www.boost.org/libs/mpl/doc/refmanual/integral-constant.html" target="_top">MPL 107 Boolean Constant</a>. 108 </p> 109<p> 110 <span class="bold"><strong>Semantics</strong></span>: Metafunction that evaluates to 111 <code class="computeroutput"><span class="identifier">mpl</span><span class="special">::</span><span class="identifier">true_</span></code> if a certain type <code class="computeroutput"><span class="identifier">T</span></code> 112 is a conforming Fusion sequence, <code class="computeroutput"><span class="identifier">mpl</span><span class="special">::</span><span class="identifier">false_</span></code> 113 otherwise. 114 </p> 115<h5> 116<a name="fusion.support.is_sequence.h4"></a> 117 <span class="phrase"><a name="fusion.support.is_sequence.header"></a></span><a class="link" href="is_sequence.html#fusion.support.is_sequence.header">Header</a> 118 </h5> 119<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">support</span><span class="special">/</span><span class="identifier">is_sequence</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 120<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">is_sequence</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 121</pre> 122<h5> 123<a name="fusion.support.is_sequence.h5"></a> 124 <span class="phrase"><a name="fusion.support.is_sequence.example"></a></span><a class="link" href="is_sequence.html#fusion.support.is_sequence.example">Example</a> 125 </h5> 126<pre class="programlisting"><span class="identifier">BOOST_MPL_ASSERT_NOT</span><span class="special">((</span> <span class="identifier">traits</span><span class="special">::</span><span class="identifier">is_sequence</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="special">));</span> 127<span class="identifier">BOOST_MPL_ASSERT_NOT</span><span class="special">((</span> <span class="identifier">is_sequence</span><span class="special"><</span> <span class="keyword">int</span> <span class="special">></span> <span class="special">));</span> 128<span class="identifier">BOOST_MPL_ASSERT</span><span class="special">((</span> <span class="identifier">traits</span><span class="special">::</span><span class="identifier">is_sequence</span><span class="special"><</span><a class="link" href="../container/list.html" title="list"><code class="computeroutput"><span class="identifier">list</span></code></a><span class="special"><></span> <span class="special">></span> <span class="special">));</span> 129<span class="identifier">BOOST_MPL_ASSERT</span><span class="special">((</span> <span class="identifier">traits</span><span class="special">::</span><span class="identifier">is_sequence</span><span class="special"><</span><a class="link" href="../container/list.html" title="list"><code class="computeroutput"><span class="identifier">list</span></code></a><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="special">></span> <span class="special">));</span> 130<span class="identifier">BOOST_MPL_ASSERT</span><span class="special">((</span> <span class="identifier">traits</span><span class="special">::</span><span class="identifier">is_sequence</span><span class="special"><</span><a class="link" href="../container/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a><span class="special"><></span> <span class="special">></span> <span class="special">));</span> 131<span class="identifier">BOOST_MPL_ASSERT</span><span class="special">((</span> <span class="identifier">traits</span><span class="special">::</span><span class="identifier">is_sequence</span><span class="special"><</span><a class="link" href="../container/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a><span class="special"><</span><span class="keyword">int</span><span class="special">></span> <span class="special">></span> <span class="special">));</span> 132</pre> 133</div> 134<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 135<td align="left"></td> 136<td align="right"><div class="copyright-footer">Copyright © 2001-2006, 2011, 2012 Joel de Guzman, 137 Dan Marsden, Tobias Schwinger<p> 138 Distributed under the Boost Software License, Version 1.0. (See accompanying 139 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>) 140 </p> 141</div></td> 142</tr></table> 143<hr> 144<div class="spirit-nav"> 145<a accesskey="p" href="../support.html"><img src="../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../support.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="is_view.html"><img src="../../../../../../doc/src/images/next.png" alt="Next"></a> 146</div> 147</body> 148</html> 149
