1<?xml version="1.0" encoding="utf-8" ?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> 4<head> 5<meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> 6<meta name="generator" content="Docutils 0.7: http://docutils.sourceforge.net/" /> 7<title>The MPL Reference Manual: single_view</title> 8<link rel="stylesheet" href="../style.css" type="text/css" /> 9</head> 10<body class="docframe refmanual"> 11<table class="header"><tr class="header"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./joint-view.html" class="navigation-link">Prev</a> <a href="./transform-view.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./joint-view.html" class="navigation-link">Back</a> <a href="./transform-view.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./views.html" class="navigation-link">Up</a> <a href="../refmanual.html" class="navigation-link">Home</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./refmanual_toc.html" class="navigation-link">Full TOC</a></span></td> 12<td class="header-group page-location"><a href="../refmanual.html" class="navigation-link">Front Page</a> / <a href="./sequences.html" class="navigation-link">Sequences</a> / <a href="./views.html" class="navigation-link">Views</a> / <a href="./single-view.html" class="navigation-link">single_view</a></td> 13</tr></table><div class="header-separator"></div> 14<div class="section" id="single-view"> 15<h1><a class="toc-backref" href="./views.html#id1421">single_view</a></h1> 16<div class="section" id="id151"> 17<h3><a class="subsection-title" href="#synopsis" name="synopsis">Synopsis</a></h3> 18<pre class="literal-block"> 19template< 20 typename T 21 > 22struct <a href="./single-view.html" class="identifier">single_view</a> 23{ 24 // <em>unspecified</em> 25 // <em>...</em> 26}; 27</pre> 28</div> 29<div class="section" id="id152"> 30<h3><a class="subsection-title" href="#description" name="description">Description</a></h3> 31<p>A view onto an arbitrary type <tt class="literal"><span class="pre">T</span></tt> as on a single-element sequence.</p> 32</div> 33<div class="section" id="id153"> 34<h3><a class="subsection-title" href="#header" name="header">Header</a></h3> 35<pre class="literal-block"> 36#include <<a href="../../../../boost/mpl/single_view.hpp" class="header">boost/mpl/single_view.hpp</a>> 37</pre> 38</div> 39<div class="section" id="id154"> 40<h3><a class="subsection-title" href="#model-of" name="model-of">Model of</a></h3> 41<ul class="simple"> 42<li><a class="reference internal" href="./random-access-sequence.html">Random Access Sequence</a></li> 43</ul> 44</div> 45<div class="section" id="id155"> 46<h3><a class="subsection-title" href="#parameters" name="parameters">Parameters</a></h3> 47<table border="1" class="docutils table"> 48<colgroup> 49<col width="19%" /> 50<col width="23%" /> 51<col width="58%" /> 52</colgroup> 53<thead valign="bottom"> 54<tr><th class="head">Parameter</th> 55<th class="head">Requirement</th> 56<th class="head">Description</th> 57</tr> 58</thead> 59<tbody valign="top"> 60<tr><td><tt class="literal"><span class="pre">T</span></tt></td> 61<td>Any type</td> 62<td>The type to be wrapped in a sequence.</td> 63</tr> 64</tbody> 65</table> 66</div> 67<div class="section" id="id156"> 68<h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3> 69<p>The semantics of an expression are defined only 70where they differ from, or are not defined in <a class="reference internal" href="./random-access-sequence.html">Random Access Sequence</a>.</p> 71<p>In the following table, <tt class="literal"><span class="pre">v</span></tt> is an instance of <tt class="literal"><span class="pre"><a href="./single-view.html" class="identifier">single_view</a></span></tt>, <tt class="literal"><span class="pre">x</span></tt> is an arbitrary type.</p> 72<table border="1" class="docutils table"> 73<colgroup> 74<col width="34%" /> 75<col width="66%" /> 76</colgroup> 77<thead valign="bottom"> 78<tr><th class="head">Expression</th> 79<th class="head">Semantics</th> 80</tr> 81</thead> 82<tbody valign="top"> 83<tr><td><pre class="first last literal-block"> 84<a href="./single-view.html" class="identifier">single_view</a><x> 85<a href="./single-view.html" class="identifier">single_view</a><x>::type 86</pre> 87</td> 88<td>A single-element <a class="reference internal" href="./random-access-sequence.html">Random Access Sequence</a> <tt class="literal"><span class="pre">v</span></tt> such that 89<tt class="literal"><span class="pre"><a href="./front.html" class="identifier">front</a><v>::type</span></tt> is identical to <tt class="literal"><span class="pre">x</span></tt>.</td> 90</tr> 91<tr><td><tt class="literal"><span class="pre"><a href="./size.html" class="identifier">size</a><v>::type</span></tt></td> 92<td>The size of <tt class="literal"><span class="pre">v</span></tt>; <tt class="literal"><span class="pre"><a href="./size.html" class="identifier">size</a><v>::value</span> <span class="pre">==</span> <span class="pre">1</span></tt>; 93see <a class="reference internal" href="./random-access-sequence.html">Random Access Sequence</a>.</td> 94</tr> 95</tbody> 96</table> 97</div> 98<div class="section" id="id157"> 99<h3><a class="subsection-title" href="#example" name="example">Example</a></h3> 100<pre class="literal-block"> 101typedef <a href="./single-view.html" class="identifier">single_view</a><int> view; 102typedef <a href="./begin.html" class="identifier">begin</a><view>::type first; 103typedef <a href="./end.html" class="identifier">end</a><view>::type last; 104 105<a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( is_same< <a href="./deref.html" class="identifier">deref</a><first>::type,int > )); 106<a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( is_same< <a href="./next.html" class="identifier">next</a><first>::type,last > )); 107<a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( is_same< <a href="./prior.html" class="identifier">prior</a><last>::type,first > )); 108 109<a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( <a href="./size.html" class="identifier">size</a><view>::value, ==, 1 ); 110</pre> 111</div> 112<div class="section" id="id158"> 113<h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3> 114<p><a class="reference internal" href="./sequences.html">Sequences</a>, <a class="reference internal" href="./views.html">Views</a>, <a class="reference internal" href="./iterator-range.html">iterator_range</a>, <a class="reference internal" href="./filter-view.html">filter_view</a>, <a class="reference internal" href="./transform-view.html">transform_view</a>, <a class="reference internal" href="./joint-view.html">joint_view</a>, <a class="reference internal" href="./zip-view.html">zip_view</a></p> 115<!-- Sequences/Views//transform_view --> 116</div> 117</div> 118 119<div class="footer-separator"></div> 120<table class="footer"><tr class="footer"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./joint-view.html" class="navigation-link">Prev</a> <a href="./transform-view.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./joint-view.html" class="navigation-link">Back</a> <a href="./transform-view.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./views.html" class="navigation-link">Up</a> <a href="../refmanual.html" class="navigation-link">Home</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./refmanual_toc.html" class="navigation-link">Full TOC</a></span></td> 121<td><div class="copyright-footer"><div class="copyright">Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams</div> 122Distributed under the Boost Software License, Version 1.0. (See accompanying 123file LICENSE_1_0.txt or copy at <a class="reference external" href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)</div></td></tr></table></body> 124</html> 125