1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html> 3<head> 4<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 5<title>Macro BOOST_PROTO_LOCAL_ITERATE</title> 6<link rel="stylesheet" href="../../doc/src/boostbook.css" type="text/css"> 7<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 8<link rel="home" href="index.html" title="The Boost C++ Libraries BoostBook Documentation Subset"> 9<link rel="up" href="proto/reference.html#header.boost.proto.repeat_hpp" title="Header <boost/proto/repeat.hpp>"> 10<link rel="prev" href="BOOST_PROTO__1_3_33_5_37_5.html" title="Macro BOOST_PROTO_REPEAT_FROM_TO_EX"> 11<link rel="next" href="BOOST_PROTO_typename_A.html" title="Macro BOOST_PROTO_typename_A"> 12</head> 13<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 14<table cellpadding="2" width="100%"><tr> 15<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../boost.png"></td> 16<td align="center"><a href="../../index.html">Home</a></td> 17<td align="center"><a href="../../libs/libraries.htm">Libraries</a></td> 18<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 19<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 20<td align="center"><a href="../../more/index.htm">More</a></td> 21</tr></table> 22<hr> 23<div class="spirit-nav"> 24<a accesskey="p" href="BOOST_PROTO__1_3_33_5_37_5.html"><img src="../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="proto/reference.html#header.boost.proto.repeat_hpp"><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="BOOST_PROTO_typename_A.html"><img src="../../doc/src/images/next.png" alt="Next"></a> 25</div> 26<div class="refentry"> 27<a name="BOOST_PROTO_LOCAL_ITERATE"></a><div class="titlepage"></div> 28<div class="refnamediv"> 29<h2><span class="refentrytitle">Macro BOOST_PROTO_LOCAL_ITERATE</span></h2> 30<p>BOOST_PROTO_LOCAL_ITERATE — Vertical repetition of a user-supplied macro.</p> 31</div> 32<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2> 33<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: <<a class="link" href="proto/reference.html#header.boost.proto.repeat_hpp" title="Header <boost/proto/repeat.hpp>">boost/proto/repeat.hpp</a>> 34 35</span>BOOST_PROTO_LOCAL_ITERATE()</pre></div> 36<div class="refsect1"> 37<a name="id-1.3.33.5.39.8.4"></a><h2>Description</h2> 38<p> 39 <code class="computeroutput">BOOST_PROTO_LOCAL_ITERATE()</code> is used generate the kind of repetitive code that is typical 40 of EDSLs built with Proto. This macro causes the user-defined macro <code class="computeroutput">BOOST_PROTO_LOCAL_MACRO()</code> to 41 be expanded with values in the range specified by <code class="computeroutput">BOOST_PROTO_LOCAL_LIMITS</code>. 42 </p> 43<p> 44 <span class="bold"><strong>Usage:</strong></span> 45 </p> 46<p> 47 </p> 48<pre class="programlisting"><span class="preprocessor">#include</span> <span class="identifier">BOOST_PROTO_LOCAL_ITERATE</span><span class="special">(</span><span class="special">)</span></pre> 49<p> 50 </p> 51<p> 52 <span class="bold"><strong>Example:</strong></span> 53 </p> 54<p> 55 </p> 56<pre class="programlisting"><span class="comment">// Generate BOOST_PROTO_MAX_ARITY-1 overloads of the</span> 57<span class="comment">// following construct() function template.</span> 58<span class="preprocessor">#define</span> <span class="identifier">BOOST_PROTO_LOCAL_MACRO</span><span class="special">(</span><span class="identifier">N</span><span class="special">,</span> <span class="identifier">typename_A</span><span class="special">,</span> <span class="identifier">A_const_ref</span><span class="special">,</span> <span class="identifier">A_const_ref_a</span><span class="special">,</span> <span class="identifier">ref_a</span><span class="special">)</span>\ 59<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">,</span> <span class="identifier">typename_A</span><span class="special">(</span><span class="identifier">N</span><span class="special">)</span><span class="special">></span> \ 60<span class="keyword">typename</span> <a class="link" href="boost/proto/result_of/make_expr.html" title="Struct template make_expr">proto::result_of::make_expr</a><span class="special"><</span> \ 61 <a class="link" href="boost/proto/tag/function.html" title="Struct function">proto::tag::function</a> \ 62 <span class="special">,</span> <span class="identifier">construct_helper</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> \ 63 <span class="special">,</span> <span class="identifier">A_const_ref</span><span class="special">(</span><span class="identifier">N</span><span class="special">)</span> \ 64<span class="special">></span><span class="special">::</span><span class="identifier">type</span> <span class="keyword">const</span> \ 65<span class="identifier">construct</span><span class="special">(</span><span class="identifier">A_const_ref_a</span><span class="special">(</span><span class="identifier">N</span><span class="special">)</span><span class="special">)</span> \ 66<span class="special">{</span> \ 67 <span class="keyword">return</span> <a class="link" href="boost/proto/make_expr.html" title="Function make_expr">proto::make_expr</a><span class="special"><</span> \ 68 <a class="link" href="boost/proto/tag/function.html" title="Struct function">proto::tag::function</a> \ 69 <span class="special">></span><span class="special">(</span> \ 70 <span class="identifier">construct_helper</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span><span class="special">(</span><span class="special">)</span> \ 71 <span class="special">,</span> <span class="identifier">ref_a</span><span class="special">(</span><span class="identifier">N</span><span class="special">)</span> \ 72 <span class="special">)</span><span class="special">;</span> \ 73<span class="special">}</span> 74<span class="preprocessor">#define</span> <span class="identifier">BOOST_PROTO_LOCAL_LIMITS</span> <span class="special">(</span><span class="number">1</span><span class="special">,</span> <span class="identifier">BOOST_PP_DEC</span><span class="special">(</span><span class="identifier">BOOST_PROTO_MAX_ARITY</span><span class="special">)</span><span class="special">)</span> 75<span class="preprocessor">#include</span> <span class="identifier">BOOST_PROTO_LOCAL_ITERATE</span><span class="special">(</span><span class="special">)</span></pre> 76<p> 77 </p> 78<p> 79 The above inclusion of <code class="computeroutput">BOOST_PROTO_LOCAL_ITERATE()</code> 80 will generate the following code: 81 </p> 82<p> 83 </p> 84<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">A0</span><span class="special">></span> 85<span class="keyword">typename</span> <a class="link" href="boost/proto/result_of/make_expr.html" title="Struct template make_expr">proto::result_of::make_expr</a><span class="special"><</span> 86 <a class="link" href="boost/proto/tag/function.html" title="Struct function">proto::tag::function</a> 87 <span class="special">,</span> <span class="identifier">construct_helper</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> 88 <span class="special">,</span> <span class="identifier">A0</span> <span class="keyword">const</span> <span class="special">&</span> 89<span class="special">></span><span class="special">::</span><span class="identifier">type</span> <span class="keyword">const</span> 90<span class="identifier">construct</span><span class="special">(</span><span class="identifier">A0</span> <span class="keyword">const</span> <span class="special">&</span> <span class="identifier">a0</span><span class="special">)</span> 91<span class="special">{</span> 92 <span class="keyword">return</span> <a class="link" href="boost/proto/make_expr.html" title="Function make_expr">proto::make_expr</a><span class="special"><</span> 93 <a class="link" href="boost/proto/tag/function.html" title="Struct function">proto::tag::function</a> 94 <span class="special">></span><span class="special">(</span> 95 <span class="identifier">construct_helper</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span><span class="special">(</span><span class="special">)</span> 96 <span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">ref</span><span class="special">(</span><span class="identifier">a0</span><span class="special">)</span> 97 <span class="special">)</span><span class="special">;</span> 98<span class="special">}</span> 99 100<span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">A0</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">A1</span><span class="special">></span> 101<span class="keyword">typename</span> <a class="link" href="boost/proto/result_of/make_expr.html" title="Struct template make_expr">proto::result_of::make_expr</a><span class="special"><</span> 102 <a class="link" href="boost/proto/tag/function.html" title="Struct function">proto::tag::function</a> 103 <span class="special">,</span> <span class="identifier">construct_helper</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span> 104 <span class="special">,</span> <span class="identifier">A0</span> <span class="keyword">const</span> <span class="special">&</span> 105 <span class="special">,</span> <span class="identifier">A1</span> <span class="keyword">const</span> <span class="special">&</span> 106<span class="special">></span><span class="special">::</span><span class="identifier">type</span> <span class="keyword">const</span> 107<span class="identifier">construct</span><span class="special">(</span><span class="identifier">A0</span> <span class="keyword">const</span> <span class="special">&</span> <span class="identifier">a0</span><span class="special">,</span> <span class="identifier">A1</span> <span class="keyword">const</span> <span class="special">&</span> <span class="identifier">a1</span><span class="special">)</span> 108<span class="special">{</span> 109 <span class="keyword">return</span> <a class="link" href="boost/proto/make_expr.html" title="Function make_expr">proto::make_expr</a><span class="special"><</span> 110 <a class="link" href="boost/proto/tag/function.html" title="Struct function">proto::tag::function</a> 111 <span class="special">></span><span class="special">(</span> 112 <span class="identifier">construct_helper</span><span class="special"><</span><span class="identifier">T</span><span class="special">></span><span class="special">(</span><span class="special">)</span> 113 <span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">ref</span><span class="special">(</span><span class="identifier">a0</span><span class="special">)</span> 114 <span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">ref</span><span class="special">(</span><span class="identifier">a1</span><span class="special">)</span> 115 <span class="special">)</span><span class="special">;</span> 116<span class="special">}</span> 117 118<span class="comment">// ... and so on, up to BOOST_PROTO_MAX_ARITY-1 arguments ...</span></pre> 119<p> 120 </p> 121<p> 122 If <code class="computeroutput">BOOST_PROTO_LOCAL_LIMITS</code> is not defined by the user, it defaults 123 to <code class="computeroutput">(1, BOOST_PROTO_MAX_ARITY)</code>. 124 </p> 125<p> 126 At each iteration, <code class="computeroutput">BOOST_PROTO_LOCAL_MACRO()</code> is invoked with the current 127 iteration number and the following 4 macro parameters: 128 </p> 129<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 130<li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_typename_A</code></li> 131<li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_A</code></li> 132<li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_A_a</code></li> 133<li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_a</code></li> 134</ul></div> 135<p> 136 If these macros are not defined by the user, they default respectively to: 137 </p> 138<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 139<li class="listitem"><code class="computeroutput"><a class="link" href="BOOST_PROTO_typename_A.html" title="Macro BOOST_PROTO_typename_A">BOOST_PROTO_typename_A</a></code></li> 140<li class="listitem"><code class="computeroutput"><a class="link" href="BOOST_PROTO_A_const_ref.html" title="Macro BOOST_PROTO_A_const_ref">BOOST_PROTO_A_const_ref</a></code></li> 141<li class="listitem"><code class="computeroutput"><a class="link" href="BOOST_PROTO_A_const_ref_a.html" title="Macro BOOST_PROTO_A_const_ref_a">BOOST_PROTO_A_const_ref_a</a></code></li> 142<li class="listitem"><code class="computeroutput"><a class="link" href="BOOST_PROTO_ref_a.html" title="Macro BOOST_PROTO_ref_a">BOOST_PROTO_ref_a</a></code></li> 143</ul></div> 144<p> 145 </p> 146<p> 147 After including <code class="computeroutput">BOOST_PROTO_LOCAL_ITERATE()</code>, the 148 following macros are automatically undefined: 149 </p> 150<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 151<li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_MACRO</code></li> 152<li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_LIMITS</code></li> 153<li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_typename_A</code></li> 154<li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_A</code></li> 155<li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_A_a</code></li> 156<li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_a</code></li> 157</ul></div> 158<p> 159 </p> 160</div> 161</div> 162<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 163<td align="left"></td> 164<td align="right"><div class="copyright-footer">Copyright © 2008 Eric Niebler<p> 165 Distributed under the Boost Software License, Version 1.0. (See accompanying 166 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>) 167 </p> 168</div></td> 169</tr></table> 170<hr> 171<div class="spirit-nav"> 172<a accesskey="p" href="BOOST_PROTO__1_3_33_5_37_5.html"><img src="../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="proto/reference.html#header.boost.proto.repeat_hpp"><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="BOOST_PROTO_typename_A.html"><img src="../../doc/src/images/next.png" alt="Next"></a> 173</div> 174</body> 175</html> 176
