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  26 <a name="BOOST_PROTO_LOCAL_ITERATE"></a><div class="titlepage"></div>
  27 <div class="refnamediv">
  28 <h2><span class="refentrytitle">Macro BOOST_PROTO_LOCAL_ITERATE</span></h2>
  29 <p>BOOST_PROTO_LOCAL_ITERATE &#8212; Vertical repetition of a user-supplied macro.</p>
  30 </div>
  31 <h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
  32 <div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: &lt;<a class="link" href="proto/reference.html#header.boost.proto.repeat_hpp" title="Header &lt;boost/proto/repeat.hpp&gt;">boost/proto/repeat.hpp</a>&gt;
  33
  34 </span>BOOST_PROTO_LOCAL_ITERATE()</pre></div>
  35 <div class="refsect1">
  36 <a name="id2842501"></a><h2>Description</h2>
  37 <p>
  38         <code class="computeroutput">BOOST_PROTO_LOCAL_ITERATE()</code> is used generate the kind of repetitive code that is typical
  39         of EDSLs built with Proto. This macro causes the user-defined macro <code class="computeroutput">BOOST_PROTO_LOCAL_MACRO()</code> to
  40         be expanded with values in the range specified by <code class="computeroutput">BOOST_PROTO_LOCAL_LIMITS</code>.
  41       </p>
  42 <p>
  43         <span class="bold"><strong>Usage:</strong></span>
  44       </p>
  45 <p>
  46         </p>
  47 <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>
  48 <p>
  49       </p>
  50 <p>
  51         <span class="bold"><strong>Example:</strong></span>
  52       </p>
  53 <p>
  54         </p>
  55 <pre class="programlisting"><span class="comment">// Generate BOOST_PROTO_MAX_ARITY-1 overloads of the</span>
  56 <span class="comment">// following construct() function template.</span>
  57 <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>\
  58 <span class="keyword">template</span><span class="special">&lt;</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">&gt;</span>                               \
  59 <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">&lt;</span>                             \
  60     <a class="link" href="boost/proto/tag/function.html" title="Struct function">proto::tag::function</a>                                          \
  61   <span class="special">,</span> <span class="identifier">construct_helper</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span>                                           \
  62   <span class="special">,</span> <span class="identifier">A_const_ref</span><span class="special">(</span><span class="identifier">N</span><span class="special">)</span>                                                \
  63 <span class="special">&gt;</span><span class="special">::</span><span class="identifier">type</span> <span class="keyword">const</span>                                                     \
  64 <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>                                       \
  65 <span class="special">{</span>                                                                 \
  66     <span class="keyword">return</span> <a class="link" href="boost/proto/make_expr_id1527104.html" title="Function make_expr">proto::make_expr</a><span class="special">&lt;</span>                                      \
  67         <a class="link" href="boost/proto/tag/function.html" title="Struct function">proto::tag::function</a>                                      \
  68     <span class="special">&gt;</span><span class="special">(</span>                                                            \
  69         <span class="identifier">construct_helper</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span><span class="special">(</span><span class="special">)</span>                                     \
  70       <span class="special">,</span> <span class="identifier">ref_a</span><span class="special">(</span><span class="identifier">N</span><span class="special">)</span>                                                  \
  71     <span class="special">)</span><span class="special">;</span>                                                            \
  72 <span class="special">}</span>
  73 <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>
  74 <span class="preprocessor">#include</span> <span class="identifier">BOOST_PROTO_LOCAL_ITERATE</span><span class="special">(</span><span class="special">)</span></pre>
  75 <p>
  76       </p>
  77 <p>
  78         The above inclusion of <code class="computeroutput">BOOST_PROTO_LOCAL_ITERATE()</code>
  79         will generate the following code:
  80       </p>
  81 <p>
  82         </p>
  83 <pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</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">&gt;</span>
  84 <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">&lt;</span>
  85     <a class="link" href="boost/proto/tag/function.html" title="Struct function">proto::tag::function</a>
  86   <span class="special">,</span> <span class="identifier">construct_helper</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span>
  87   <span class="special">,</span> <span class="identifier">A0</span> <span class="keyword">const</span> <span class="special">&amp;</span>
  88 <span class="special">&gt;</span><span class="special">::</span><span class="identifier">type</span> <span class="keyword">const</span>
  89 <span class="identifier">construct</span><span class="special">(</span><span class="identifier">A0</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">a0</span><span class="special">)</span>
  90 <span class="special">{</span>
  91     <span class="keyword">return</span> <a class="link" href="boost/proto/make_expr_id1527104.html" title="Function make_expr">proto::make_expr</a><span class="special">&lt;</span>
  92         <a class="link" href="boost/proto/tag/function.html" title="Struct function">proto::tag::function</a>
  93     <span class="special">&gt;</span><span class="special">(</span>
  94         <span class="identifier">construct_helper</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span><span class="special">(</span><span class="special">)</span>
  95       <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>
  96     <span class="special">)</span><span class="special">;</span>
  97 <span class="special">}</span>
  98
  99 <span class="keyword">template</span><span class="special">&lt;</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">&gt;</span>
 100 <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">&lt;</span>
 101     <a class="link" href="boost/proto/tag/function.html" title="Struct function">proto::tag::function</a>
 102   <span class="special">,</span> <span class="identifier">construct_helper</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span>
 103   <span class="special">,</span> <span class="identifier">A0</span> <span class="keyword">const</span> <span class="special">&amp;</span>
 104   <span class="special">,</span> <span class="identifier">A1</span> <span class="keyword">const</span> <span class="special">&amp;</span>
 105 <span class="special">&gt;</span><span class="special">::</span><span class="identifier">type</span> <span class="keyword">const</span>
 106 <span class="identifier">construct</span><span class="special">(</span><span class="identifier">A0</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">a0</span><span class="special">,</span> <span class="identifier">A1</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">a1</span><span class="special">)</span>
 107 <span class="special">{</span>
 108     <span class="keyword">return</span> <a class="link" href="boost/proto/make_expr_id1527104.html" title="Function make_expr">proto::make_expr</a><span class="special">&lt;</span>
 109         <a class="link" href="boost/proto/tag/function.html" title="Struct function">proto::tag::function</a>
 110     <span class="special">&gt;</span><span class="special">(</span>
 111         <span class="identifier">construct_helper</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span><span class="special">(</span><span class="special">)</span>
 112       <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>
 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">a1</span><span class="special">)</span>
 114     <span class="special">)</span><span class="special">;</span>
 115 <span class="special">}</span>
 116
 117 <span class="comment">// ... and so on, up to BOOST_PROTO_MAX_ARITY-1 arguments ...</span></pre>
 118 <p>
 119       </p>
 120 <p>
 121         If <code class="computeroutput">BOOST_PROTO_LOCAL_LIMITS</code> is not defined by the user, it defaults
 122         to <code class="computeroutput">(1, BOOST_PROTO_MAX_ARITY)</code>.
 123       </p>
 124 <p>
 125         At each iteration, <code class="computeroutput">BOOST_PROTO_LOCAL_MACRO()</code> is invoked with the current
 126         iteration number and the following 4 macro parameters:
 127         </p>
 128 <div class="itemizedlist"><ul class="itemizedlist" type="disc">
 129 <li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_typename_A</code></li>
 130 <li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_A</code></li>
 131 <li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_A_a</code></li>
 132 <li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_a</code></li>
 133 </ul></div>
 134 <p>
 135         If these macros are not defined by the user, they default respectively to:
 136         </p>
 137 <div class="itemizedlist"><ul class="itemizedlist" type="disc">
 138 <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>
 139 <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>
 140 <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>
 141 <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>
 142 </ul></div>
 143 <p>
 144       </p>
 145 <p>
 146         After including <code class="computeroutput">BOOST_PROTO_LOCAL_ITERATE()</code>, the
 147         following macros are automatically undefined:
 148         </p>
 149 <div class="itemizedlist"><ul class="itemizedlist" type="disc">
 150 <li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_MACRO</code></li>
 151 <li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_LIMITS</code></li>
 152 <li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_typename_A</code></li>
 153 <li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_A</code></li>
 154 <li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_A_a</code></li>
 155 <li class="listitem"><code class="computeroutput">BOOST_PROTO_LOCAL_a</code></li>
 156 </ul></div>
 157 <p>
 158       </p>
 159 </div>
 160 </div>
 161 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 162 <td align="left"></td>
 163 <td align="right"><div class="copyright-footer">Copyright &#169; 2008 Eric Niebler<p>
 164         Distributed under the Boost Software License, Version 1.0. (See accompanying
 165         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>)
 166       </p>
 167 </div></td>
 168 </tr></table>
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