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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"> | |
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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: apply_wrap</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="./apply.html" class="navigation-link">Prev</a> <a href="./unpack-args.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./apply.html" class="navigation-link">Back</a> <a href="./unpack-args.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./invocation.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="./metafunctions.html" class="navigation-link">Metafunctions</a> / <a href="./invocation.html" class="navigation-link">Invocation</a> / <a href="./apply-wrap.html" class="navigation-link">apply_wrap</a></td> | |
13 | </tr></table><div class="header-separator"></div> | |
14 | <div class="section" id="apply-wrap"> | |
15 | <h1><a class="toc-backref" href="./invocation.html#id1526">apply_wrap</a></h1> | |
16 | <div class="section" id="id894"> | |
17 | <h3><a class="subsection-title" href="#synopsis" name="synopsis">Synopsis</a></h3> | |
18 | <pre class="literal-block"> | |
19 | template< | |
20 | typename F | |
21 | > | |
22 | struct apply_wrap0 | |
23 | { | |
24 | typedef <em>unspecified</em> type; | |
25 | }; | |
26 | ||
27 | template< | |
28 | typename F, typename A1 | |
29 | > | |
30 | struct apply_wrap1 | |
31 | { | |
32 | typedef <em>unspecified</em> type; | |
33 | }; | |
34 | ||
35 | <em>...</em> | |
36 | ||
37 | template< | |
38 | typename F, typename A1,<em>...</em> typename An | |
39 | > | |
40 | struct <a href="./apply-wrap.html" class="identifier">apply_wrap</a><em>n</em> | |
41 | { | |
42 | typedef <em>unspecified</em> type; | |
43 | }; | |
44 | </pre> | |
45 | </div> | |
46 | <div class="section" id="id895"> | |
47 | <h3><a class="subsection-title" href="#description" name="description">Description</a></h3> | |
48 | <p>Invokes a <a class="reference internal" href="./metafunction-class.html">Metafunction Class</a> <tt class="literal"><span class="pre">F</span></tt> with arguments <tt class="literal"><span class="pre">A1</span></tt>,... <tt class="literal"><span class="pre">An</span></tt>.</p> | |
49 | <p>In essence, <tt class="literal"><span class="pre"><a href="./apply-wrap.html" class="identifier">apply_wrap</a></span></tt> forms are nothing more than syntactic wrappers around | |
50 | <tt class="literal"><span class="pre">F::<a href="./apply.html" class="identifier">apply</a><A1,...</span> <span class="pre">An>::type</span></tt> / <tt class="literal"><span class="pre">F::<a href="./apply.html" class="identifier">apply</a>::type</span></tt> expressions (hence the name). | |
51 | They provide a more concise notation and higher portability than their | |
52 | underlaying constructs at the cost of an extra template instantiation.</p> | |
53 | </div> | |
54 | <div class="section" id="id896"> | |
55 | <h3><a class="subsection-title" href="#header" name="header">Header</a></h3> | |
56 | <pre class="literal-block"> | |
57 | #include <<a href="../../../../boost/mpl/apply_wrap.hpp" class="header">boost/mpl/apply_wrap.hpp</a>> | |
58 | </pre> | |
59 | </div> | |
60 | <div class="section" id="id897"> | |
61 | <h3><a class="subsection-title" href="#parameters" name="parameters">Parameters</a></h3> | |
62 | <table border="1" class="docutils table"> | |
63 | <colgroup> | |
64 | <col width="15%" /> | |
65 | <col width="36%" /> | |
66 | <col width="48%" /> | |
67 | </colgroup> | |
68 | <thead valign="bottom"> | |
69 | <tr><th class="head">Parameter</th> | |
70 | <th class="head">Requirement</th> | |
71 | <th class="head">Description</th> | |
72 | </tr> | |
73 | </thead> | |
74 | <tbody valign="top"> | |
75 | <tr><td><tt class="literal"><span class="pre">F</span></tt></td> | |
76 | <td><a class="reference internal" href="./metafunction-class.html">Metafunction Class</a></td> | |
77 | <td>A metafunction class to invoke.</td> | |
78 | </tr> | |
79 | <tr><td><tt class="literal"><span class="pre">A1</span></tt>,... <tt class="literal"><span class="pre">An</span></tt></td> | |
80 | <td>Any type</td> | |
81 | <td>Invocation arguments.</td> | |
82 | </tr> | |
83 | </tbody> | |
84 | </table> | |
85 | </div> | |
86 | <div class="section" id="id898"> | |
87 | <h3><a class="subsection-title" href="#expression-semantics" name="expression-semantics">Expression semantics</a></h3> | |
88 | <p>For any <a class="reference internal" href="./metafunction-class.html">Metafunction Class</a> <tt class="literal"><span class="pre">f</span></tt> and arbitrary types <tt class="literal"><span class="pre">a1</span></tt>,... <tt class="literal"><span class="pre">an</span></tt>:</p> | |
89 | <pre class="literal-block"> | |
90 | typedef <a href="./apply-wrap.html" class="identifier">apply_wrap</a><em>n</em><f,a1,<em>...</em>an>::type t; | |
91 | </pre> | |
92 | <table class="docutils field-list" frame="void" rules="none"> | |
93 | <col class="field-name" /> | |
94 | <col class="field-body" /> | |
95 | <tbody valign="top"> | |
96 | <tr class="field"><th class="field-name">Return type:</th><td class="field-body">Any type.</td> | |
97 | </tr> | |
98 | <tr class="field"><th class="field-name">Semantics:</th><td class="field-body">If <tt class="literal"><span class="pre">n</span> <span class="pre">></span> <span class="pre">0</span></tt>, equivalent to <tt class="literal"><span class="pre">typedef</span> <span class="pre">f::<a href="./apply.html" class="identifier">apply</a><a1,...</span> <span class="pre">an>::type</span> <span class="pre">t;</span></tt>, | |
99 | otherwise equivalent to either <tt class="literal"><span class="pre">typedef</span> <span class="pre">f::<a href="./apply.html" class="identifier">apply</a>::type</span> <span class="pre">t;</span></tt> or | |
100 | <tt class="literal"><span class="pre">typedef</span> <span class="pre">f::<a href="./apply.html" class="identifier">apply</a><>::type</span> <span class="pre">t;</span></tt> depending on whether <tt class="literal"><span class="pre">f::<a href="./apply.html" class="identifier">apply</a></span></tt> is | |
101 | a class or a class template.</td> | |
102 | </tr> | |
103 | </tbody> | |
104 | </table> | |
105 | </div> | |
106 | <div class="section" id="id899"> | |
107 | <h3><a class="subsection-title" href="#example" name="example">Example</a></h3> | |
108 | <pre class="literal-block"> | |
109 | struct f0 | |
110 | { | |
111 | template< typename T = int > struct <a href="./apply.html" class="identifier">apply</a> | |
112 | { | |
113 | typedef char type; | |
114 | }; | |
115 | }; | |
116 | ||
117 | struct g0 | |
118 | { | |
119 | struct <a href="./apply.html" class="identifier">apply</a> { typedef char type; }; | |
120 | }; | |
121 | ||
122 | struct f2 | |
123 | { | |
124 | template< typename T1, typename T2 > struct <a href="./apply.html" class="identifier">apply</a> | |
125 | { | |
126 | typedef T2 type; | |
127 | }; | |
128 | }; | |
129 | ||
130 | ||
131 | typedef <a href="./apply-wrap.html" class="identifier">apply_wrap</a><tt class="literal"><span class="pre">0</span></tt>< f0 >::type r1; | |
132 | typedef <a href="./apply-wrap.html" class="identifier">apply_wrap</a><tt class="literal"><span class="pre">0</span></tt>< g0 >::type r2; | |
133 | typedef <a href="./apply-wrap.html" class="identifier">apply_wrap</a><tt class="literal"><span class="pre">2</span></tt>< f2,int,char >::type r3; | |
134 | ||
135 | <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( is_same<r1,char> )); | |
136 | <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( is_same<r2,char> )); | |
137 | <a href="./assert.html" class="identifier">BOOST_MPL_ASSERT</a>(( is_same<r3,char> )); | |
138 | </pre> | |
139 | </div> | |
140 | <div class="section" id="id900"> | |
141 | <h3><a class="subsection-title" href="#see-also" name="see-also">See also</a></h3> | |
142 | <p><a class="reference internal" href="./metafunctions.html">Metafunctions</a>, <a class="reference internal" href="./invocation.html">invocation</a>, <a class="reference internal" href="./apply.html">apply</a>, <a class="reference internal" href="./lambda.html">lambda</a>, <a class="reference internal" href="./quote.html">quote</a>, <a class="reference internal" href="./bind.html">bind</a>, <a class="reference internal" href="./protect.html">protect</a></p> | |
143 | <!-- Metafunctions/Invocation//unpack_args |30 --> | |
144 | </div> | |
145 | </div> | |
146 | ||
147 | <div class="footer-separator"></div> | |
148 | <table class="footer"><tr class="footer"><td class="header-group navigation-bar"><span class="navigation-group"><a href="./apply.html" class="navigation-link">Prev</a> <a href="./unpack-args.html" class="navigation-link">Next</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./apply.html" class="navigation-link">Back</a> <a href="./unpack-args.html" class="navigation-link">Along</a></span><span class="navigation-group-separator"> | </span><span class="navigation-group"><a href="./invocation.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> | |
149 | <td><div class="copyright-footer"><div class="copyright">Copyright © 2001-2009 Aleksey Gurtovoy and David Abrahams</div> | |
150 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
151 | file 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> | |
152 | </html> |