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: push_front</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="./push-back.html" class="navigation-link">Prev</a> <a href="./sequence-tag.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./push-back.html" class="navigation-link">Back</a> <a href="./sequence-tag.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./intrinsic-metafunctions.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="./intrinsic-metafunctions.html" class="navigation-link">Intrinsic Metafunctions</a> / <a href="./push-front.html" class="navigation-link">push_front</a></td> 13</tr></table><div class="header-separator"></div> 14<div class="section" id="push-front"> 15<h1><a class="toc-backref" href="./intrinsic-metafunctions.html#id1444">push_front</a></h1> 16<div class="section" id="id345"> 17<h3><a class="subsection-title" href="#synopsis" name="synopsis">Synopsis</a></h3> 18<pre class="literal-block"> 19template< 20 typename Sequence 21 , typename T 22 > 23struct <a href="./push-front.html" class="identifier">push_front</a> 24{ 25 typedef <em>unspecified</em> type; 26}; 27</pre> 28</div> 29<div class="section" id="id346"> 30<h3><a class="subsection-title" href="#description" name="description">Description</a></h3> 31<p><tt class="literal"><span class="pre"><a href="./push-front.html" class="identifier">push_front</a></span></tt> performs an insertion at the beginning of the sequence with guaranteed <em>O(1)</em> 32complexity.</p> 33</div> 34<div class="section" id="id347"> 35<h3><a class="subsection-title" href="#header" name="header">Header</a></h3> 36<pre class="literal-block"> 37#include <<a href="../../../../boost/mpl/push_front.hpp" class="header">boost/mpl/push_front.hpp</a>> 38</pre> 39</div> 40<div class="section" id="id348"> 41<h3><a class="subsection-title" href="#model-of" name="model-of">Model of</a></h3> 42<p><a class="reference internal" href="./tag-dispatched-metafunction.html">Tag Dispatched Metafunction</a></p> 43</div> 44<div class="section" id="id349"> 45<h3><a class="subsection-title" href="#parameters" name="parameters">Parameters</a></h3> 46<table border="1" class="docutils table"> 47<colgroup> 48<col width="16%" /> 49<col width="33%" /> 50<col width="51%" /> 51</colgroup> 52<thead valign="bottom"> 53<tr><th class="head">Parameter</th> 54<th class="head">Requirement</th> 55<th class="head">Description</th> 56</tr> 57</thead> 58<tbody valign="top"> 59<tr><td><tt class="literal"><span class="pre">Sequence</span></tt></td> 60<td><a class="reference internal" href="./front-extensible-sequence.html">Front Extensible Sequence</a></td> 61<td>A sequence to insert into.</td> 62</tr> 63<tr><td><tt class="literal"><span class="pre">T</span></tt></td> 64<td>Any type</td> 65<td>The element to be inserted.</td> 66</tr> 67</tbody> 68</table> 69</div> 70<div class="section" id="id350"> 71<h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3> 72<p>For any <a class="reference internal" href="./front-extensible-sequence.html">Front Extensible Sequence</a> <tt class="literal"><span class="pre">s</span></tt> and arbitrary type <tt class="literal"><span class="pre">x</span></tt>:</p> 73<pre class="literal-block"> 74typedef <a href="./push-front.html" class="identifier">push_front</a><s,x>::type r; 75</pre> 76<table class="docutils field-list" frame="void" rules="none"> 77<col class="field-name" /> 78<col class="field-body" /> 79<tbody valign="top"> 80<tr class="field"><th class="field-name">Return type:</th><td class="field-body"><p class="first"><a class="reference internal" href="./front-extensible-sequence.html">Front Extensible Sequence</a>.</p> 81</td> 82</tr> 83<tr class="field"><th class="field-name">Semantics:</th><td class="field-body"><p class="first">Equivalent to</p> 84<pre class="literal-block"> 85typedef <a href="./insert.html" class="identifier">insert</a>< s,<a href="./begin.html" class="identifier">begin</a><s>::type,x >::type r; 86</pre> 87</td> 88</tr> 89<tr class="field"><th class="field-name">Postcondition:</th><td class="field-body"><p class="first last"><tt class="literal"><span class="pre"><a href="./size.html" class="identifier">size</a><r>::value</span> <span class="pre">==</span> <span class="pre"><a href="./size.html" class="identifier">size</a><s>::value</span> <span class="pre">+</span> <span class="pre">1</span></tt>; 90<tt class="literal"><span class="pre"><a href="./front.html" class="identifier">front</a><r>::type</span></tt> is identical to <tt class="literal"><span class="pre">x</span></tt>.</p> 91</td> 92</tr> 93</tbody> 94</table> 95</div> 96<div class="section" id="id351"> 97<h3><a class="subsection-title" href="#complexity" name="complexity">Complexity</a></h3> 98<p>Amortized constant time.</p> 99</div> 100<div class="section" id="id352"> 101<h3><a class="subsection-title" href="#example" name="example">Example</a></h3> 102<pre class="literal-block"> 103typedef <a href="./vector-c.html" class="identifier">vector_c</a><int,1,2,3,5,8,13,21> v; 104<a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( <a href="./size.html" class="identifier">size</a><v>::value, ==, 7 ); 105 106typedef <a href="./push-front.html" class="identifier">push_front</a>< v,<a href="./integral-c.html" class="identifier">integral_c</a><int,1> >::type fibonacci; 107<a href="./assert-relation.html" class="identifier">BOOST_MPL_ASSERT_RELATION</a>( <a href="./size.html" class="identifier">size</a><fibonacci>::value, ==, 8 ); 108 109<a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( <a href="./equal.html" class="identifier">equal</a>< 110 fibonacci 111 , <a href="./vector-c.html" class="identifier">vector_c</a><int,1,1,2,3,5,8,13,21> 112 , <a href="./equal-to.html" class="identifier">equal_to</a><_,_> 113 > )); 114</pre> 115</div> 116<div class="section" id="id353"> 117<h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3> 118<p><a class="reference internal" href="./front-extensible-sequence.html">Front Extensible Sequence</a>, <a class="reference internal" href="./insert.html">insert</a>, <a class="reference internal" href="./pop-front.html">pop_front</a>, <a class="reference internal" href="./front.html">front</a>, <a class="reference internal" href="./push-back.html">push_back</a></p> 119<!-- Sequences/Intrinsic Metafunctions//sequence_tag --> 120</div> 121</div> 122 123<div class="footer-separator"></div> 124<table class="footer"><tr class="footer"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./push-back.html" class="navigation-link">Prev</a> <a href="./sequence-tag.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./push-back.html" class="navigation-link">Back</a> <a href="./sequence-tag.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./intrinsic-metafunctions.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> 125<td><div class="copyright-footer"><div class="copyright">Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams</div> 126Distributed under the Boost Software License, Version 1.0. (See accompanying 127file 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> 128</html> 129