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  28 <h2><span class="refentrytitle">Macro BOOST_PROTO_DEFINE_OPERATORS</span></h2>
  29 <p>BOOST_PROTO_DEFINE_OPERATORS &#8212; Defines a complete set of expression template-building operator overloads for use
  30       with non-Proto terminal types.</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: &lt;<a class="link" href="proto/reference.html#header.boost.proto.operators_hpp" title="Header &lt;boost/proto/operators.hpp&gt;">boost/proto/operators.hpp</a>&gt;
  34
  35 </span>BOOST_PROTO_DEFINE_OPERATORS(Trait, Domain)</pre></div>
  36 <div class="refsect1">
  37 <a name="idp378531216"></a><h2>Description</h2>
  38 <p>
  39         With <code class="computeroutput">BOOST_PROTO_DEFINE_OPERATORS()</code>, it is possible to
  40         non-intrusively adapt an existing (non-Proto) type to be a Proto terminal.
  41       </p>
  42 <p>
  43         <code class="computeroutput">Trait</code> is the name of a unary Boolean metafunction that returns
  44         true for any types you would like to treat as Proto terminals.
  45       </p>
  46 <p>
  47         <code class="computeroutput">Domain</code> is the name of the Proto domain associated with
  48         these new Proto terminals. You may use
  49         <code class="computeroutput"><a class="link" href="boost/proto/default_domain.html" title="Struct default_domain">proto::default_domain</a></code>
  50         for the <code class="computeroutput">Domain</code> if you do not wish to associate these terminals
  51         with any domain.
  52       </p>
  53 <p>
  54         <span class="bold"><strong>Example:</strong></span>
  55         </p>
  56 <pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">My</span> <span class="special">{</span>
  57   <span class="comment">// A non-Proto terminal type</span>
  58   <span class="keyword">struct</span> <span class="identifier">S</span> <span class="special">{</span><span class="special">}</span><span class="special">;</span>
  59
  60   <span class="comment">// A unary Boolean metafunction that returns true for type S</span>
  61   <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span> <span class="keyword">struct</span> <span class="identifier">IsS</span> <span class="special">:</span> <span class="identifier">mpl</span><span class="special">::</span><span class="identifier">false_</span> <span class="special">{</span><span class="special">}</span><span class="special">;</span>
  62   <span class="keyword">template</span><span class="special">&lt;</span><span class="special">&gt;</span> <span class="keyword">struct</span> <span class="identifier">IsS</span><span class="special">&lt;</span><span class="identifier">S</span><span class="special">&gt;</span> <span class="special">:</span> <span class="identifier">mpl</span><span class="special">::</span><span class="identifier">true_</span> <span class="special">{</span><span class="special">}</span><span class="special">;</span>
  63
  64   <span class="comment">// Make S a Proto terminal non-intrusively by defining the</span>
  65   <span class="comment">// appropriate operator overloads. This should be in the same</span>
  66   <span class="comment">// namespace as S so that these overloads can be found by</span>
  67   <span class="comment">// argument-dependent lookup</span>
  68   <a class="link" href="BOOST_PROTO_DEFINE_OPERATORS.html" title="Macro BOOST_PROTO_DEFINE_OPERATORS">BOOST_PROTO_DEFINE_OPERATORS</a><span class="special">(</span><span class="identifier">IsS</span><span class="special">,</span> <span class="identifier">proto</span><span class="special">::</span><span class="identifier">default_domain</span><span class="special">)</span>
  69 <span class="special">}</span>
  70
  71 <span class="keyword">int</span> <span class="identifier">main</span><span class="special">(</span><span class="special">)</span> <span class="special">{</span>
  72   <span class="identifier">My</span><span class="special">::</span><span class="identifier">S</span> <span class="identifier">s1</span><span class="special">,</span> <span class="identifier">s2</span><span class="special">;</span>
  73
  74   <span class="comment">// OK, this builds a Proto expression template:</span>
  75   <span class="identifier">s1</span> <span class="special">+</span> <span class="identifier">s2</span><span class="special">;</span>
  76 <span class="special">}</span></pre>
  77 <p>
  78       </p>
  79 </div>
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  82 <td align="left"></td>
  83 <td align="right"><div class="copyright-footer">Copyright &#169; 2008 Eric Niebler<p>
  84         Distributed under the Boost Software License, Version 1.0. (See accompanying
  85         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>)
  86       </p>
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