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  25 <div class="section">
  26 <div class="titlepage"><div><div><h4 class="title">
  27 <a name="phoenix.inside.expression.boilerplate_macros"></a><a class="link" href="boilerplate_macros.html" title="Boilerplate Macros">Boilerplate
  28         Macros</a>
  29 </h4></div></div></div>
  30 <div class="toc"><dl class="toc">
  31 <dt><span class="section"><a href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression">BOOST_PHOENIX_DEFINE_EXPRESSION</a></span></dt>
  32 <dt><span class="section"><a href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_vararg">BOOST_PHOENIX_DEFINE_EXPRESSION_VARARG</a></span></dt>
  33 <dt><span class="section"><a href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext">BOOST_PHOENIX_DEFINE_EXPRESSION_EXT</a></span></dt>
  34 <dt><span class="section"><a href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext_vararg">BOOST_PHOENIX_DEFINE_EXPRESSION_EXT_VARARG</a></span></dt>
  35 </dl></div>
  36 <p>
  37           When having more and more expressions, you start to realize that this is
  38           a very repetetive task. Phoenix provides boilerplate macros that make defining
  39           Phoenix Expressions as you have seen in the <a class="link" href="../expression.html" title="Phoenix Expressions">previous
  40           section</a> look like a piece of cake.
  41         </p>
  42 <div class="section">
  43 <div class="titlepage"><div><div><h5 class="title">
  44 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression"></a><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression" title="BOOST_PHOENIX_DEFINE_EXPRESSION">BOOST_PHOENIX_DEFINE_EXPRESSION</a>
  45 </h5></div></div></div>
  46 <h6>
  47 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression.h0"></a>
  48             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression.description"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression.description">Description</a>
  49           </h6>
  50 <p>
  51             <code class="computeroutput"><span class="identifier">BOOST_PHOENIX_DEFINE_EXPRESSION</span></code>
  52             is a macro that can be used to generate all the necessary boilerplate
  53             to create Phoenix Expressions
  54           </p>
  55 <h6>
  56 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression.h1"></a>
  57             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression.synopsis"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression.synopsis">Synopsis</a>
  58           </h6>
  59 <pre class="programlisting"><span class="identifier">BOOST_PHOENIX_DEFINE_EXPRESSION</span><span class="special">(</span>
  60     <span class="special">(</span><span class="identifier">namespace_seq</span><span class="special">)(</span><span class="identifier">name</span><span class="special">)</span>
  61   <span class="special">,</span> <span class="special">(</span><span class="identifier">child_grammar0</span><span class="special">)</span>
  62     <span class="special">(</span><span class="identifier">child_grammar1</span><span class="special">)</span>
  63     <span class="special">...</span>
  64 <span class="special">)</span>
  65 </pre>
  66 <h6>
  67 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression.h2"></a>
  68             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression.semantics"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression.semantics">Semantics</a>
  69           </h6>
  70 <p>
  71             The above macro generates the necessary code for an expression <code class="computeroutput"><span class="identifier">name</span></code> in namespace <code class="computeroutput"><span class="identifier">namespace_seq</span></code>.
  72             The sequence of <code class="computeroutput"><span class="special">(</span><span class="identifier">child_grammarN</span><span class="special">)</span></code> declares how many children the expression
  73             will have and what <code class="computeroutput"><span class="identifier">proto</span><span class="special">::</span><span class="identifier">grammar</span></code>
  74             they match.
  75           </p>
  76 <p>
  77             The macro should be used at global scope. <code class="computeroutput"><span class="identifier">namespace_seq</span></code>
  78             shall be the sequence of namespaces under which the following symbols
  79             will be defined:
  80           </p>
  81 <pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">tag</span>
  82 <span class="special">{</span>
  83     <span class="keyword">struct</span> <span class="identifier">name</span><span class="special">;</span>
  84 <span class="special">}</span>
  85
  86 <span class="keyword">namespace</span> <span class="identifier">expression</span>
  87 <span class="special">{</span>
  88     <span class="keyword">template</span> <span class="special">&lt;</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> <span class="keyword">typename</span> <span class="identifier">AN</span><span class="special">&gt;</span>
  89     <span class="keyword">struct</span> <span class="identifier">name</span>
  90         <span class="special">:</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">phoenix</span><span class="special">::</span><span class="identifier">expr</span><span class="special">&lt;</span>
  91             <span class="identifier">tag</span><span class="special">::</span><span class="identifier">name</span>
  92           <span class="special">,</span> <span class="identifier">A0</span>
  93           <span class="special">,</span> <span class="identifier">A1</span>
  94             <span class="special">...</span>
  95           <span class="special">,</span> <span class="identifier">AN</span>
  96         <span class="special">&gt;</span>
  97 <span class="special">}</span>
  98
  99 <span class="keyword">namespace</span> <span class="identifier">rule</span>
 100 <span class="special">{</span>
 101     <span class="keyword">struct</span> <span class="identifier">name</span>
 102         <span class="special">:</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">phoenix</span><span class="special">::</span><span class="identifier">expr</span><span class="special">&lt;</span>
 103             <span class="identifier">child_grammar0</span>
 104           <span class="special">,</span> <span class="identifier">child_grammar1</span>
 105             <span class="special">...</span>
 106           <span class="special">,</span> <span class="identifier">child_grammarN</span>
 107         <span class="special">&gt;</span>
 108     <span class="special">{};</span>
 109 <span class="special">}</span>
 110
 111 <span class="keyword">namespace</span> <span class="identifier">functional</span>
 112 <span class="special">{</span>
 113     <span class="keyword">struct</span> <span class="identifier">make_name</span><span class="special">;</span> <span class="comment">// A polymorphic function object that can be called to create the expression node</span>
 114 <span class="special">}</span>
 115
 116 <span class="keyword">namespace</span> <span class="identifier">result_of</span>
 117 <span class="special">{</span>
 118     <span class="keyword">template</span> <span class="special">&lt;</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> <span class="keyword">typename</span> <span class="identifier">AN</span><span class="special">&gt;</span>
 119     <span class="keyword">struct</span> <span class="identifier">make_name</span><span class="special">;</span> <span class="comment">// The result type of the expression node</span>
 120 <span class="special">}</span>
 121
 122 <span class="comment">// convenience polymorphic function to create an expression node</span>
 123 <span class="keyword">template</span> <span class="special">&lt;</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> <span class="keyword">typename</span> <span class="identifier">AN</span><span class="special">&gt;</span>
 124 <span class="identifier">result_of</span><span class="special">::</span><span class="identifier">make_name</span><span class="special">&lt;</span><span class="identifier">A0</span><span class="special">,</span> <span class="identifier">A1</span> <span class="special">...</span> <span class="identifier">AN</span><span class="special">&gt;</span>
 125 <span class="identifier">make_name</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> <span class="identifier">AN</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">an</span><span class="special">);</span>
 126 </pre>
 127 <p>
 128             This macros also adds a specialization for <code class="computeroutput"><span class="identifier">meta_grammar</span><span class="special">::</span><span class="identifier">case_</span><span class="special">&lt;</span><span class="identifier">tag</span><span class="special">::</span><span class="identifier">name</span><span class="special">&gt;</span></code> to enable the rule for further use
 129             in actions.
 130           </p>
 131 <h6>
 132 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression.h3"></a>
 133             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression.header"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression.header">Header</a>
 134           </h6>
 135 <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">phoenix</span><span class="special">/</span><span class="identifier">core</span><span class="special">/</span><span class="identifier">expression</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
 136 </pre>
 137 <h6>
 138 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression.h4"></a>
 139             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression.example"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression.example">Example</a>
 140           </h6>
 141 <p>
 142             The example from the previous section can be rewritten as:
 143           </p>
 144 <pre class="programlisting"><span class="identifier">BOOST_PHOENIX_DEFINE_EXPRESSION</span><span class="special">(</span>
 145     <span class="special">(</span><span class="identifier">plus</span><span class="special">)</span>
 146   <span class="special">,</span> <span class="special">(</span><span class="identifier">meta_grammar</span><span class="special">)</span>               <span class="comment">// Lhs</span>
 147     <span class="special">(</span><span class="identifier">meta_grammar</span><span class="special">)</span>               <span class="comment">// Rhs</span>
 148 <span class="special">)</span>
 149
 150 <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Lhs</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Rhs</span><span class="special">&gt;</span>
 151 <span class="keyword">typename</span> <span class="identifier">plus</span><span class="special">&lt;</span><span class="identifier">Lhs</span><span class="special">,</span> <span class="identifier">Rhs</span><span class="special">&gt;::</span><span class="identifier">type</span>
 152 <span class="identifier">plus</span><span class="special">(</span><span class="identifier">Lhs</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">lhs</span><span class="special">,</span> <span class="identifier">Rhs</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">rhs</span><span class="special">)</span>
 153 <span class="special">{</span>
 154     <span class="keyword">return</span> <span class="identifier">expression</span><span class="special">::</span><span class="identifier">plus</span><span class="special">&lt;</span><span class="identifier">Lhs</span><span class="special">,</span> <span class="identifier">Rhs</span><span class="special">&gt;::</span><span class="identifier">make</span><span class="special">(</span><span class="identifier">lhs</span><span class="special">,</span> <span class="identifier">rhs</span><span class="special">);</span>
 155 <span class="special">}</span>
 156 </pre>
 157 </div>
 158 <div class="section">
 159 <div class="titlepage"><div><div><h5 class="title">
 160 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_vararg"></a><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_vararg" title="BOOST_PHOENIX_DEFINE_EXPRESSION_VARARG">BOOST_PHOENIX_DEFINE_EXPRESSION_VARARG</a>
 161 </h5></div></div></div>
 162 <h6>
 163 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_vararg.h0"></a>
 164             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_vararg.description"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_vararg.description">Description</a>
 165           </h6>
 166 <p>
 167             <code class="computeroutput"><span class="identifier">BOOST_PHOENIX_DEFINE_EXPRESSION_VARARG</span></code>
 168             is a macro that can be used to generate all the necessary boilerplate
 169             to create Phoenix Expressions
 170           </p>
 171 <h6>
 172 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_vararg.h1"></a>
 173             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_vararg.synopsis"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_vararg.synopsis">Synopsis</a>
 174           </h6>
 175 <pre class="programlisting"><span class="identifier">BOOST_PHOENIX_DEFINE_EXPRESSION_VARARG</span><span class="special">(</span>
 176     <span class="special">(</span><span class="identifier">namespace_seq</span><span class="special">)(</span><span class="identifier">name</span><span class="special">)</span>
 177   <span class="special">,</span> <span class="special">(</span><span class="identifier">child_grammar0</span><span class="special">)</span>
 178     <span class="special">(</span><span class="identifier">child_grammar1</span><span class="special">)</span>
 179     <span class="special">...</span>
 180     <span class="special">(</span><span class="identifier">child_grammarN</span><span class="special">)</span>
 181   <span class="special">,</span> <span class="identifier">N</span>
 182 <span class="special">)</span>
 183 </pre>
 184 <h6>
 185 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_vararg.h2"></a>
 186             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_vararg.semantics"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_vararg.semantics">Semantics</a>
 187           </h6>
 188 <p>
 189             The above macro generates the necessary code for an expression <code class="computeroutput"><span class="identifier">name</span></code> in namespace <code class="computeroutput"><span class="identifier">namespace_seq</span></code>.
 190             <code class="computeroutput"><span class="identifier">N</span></code> is the maximum number
 191             of variable children. All but the last elements in the grammar sequence
 192             are required children of the expression, and the last denotes a variable
 193             number of children. The number of children an expression of this kind
 194             can hold is therefor <code class="computeroutput"><span class="identifier">N</span><span class="special">-</span><span class="number">1</span></code> plus
 195             the size of the sequence
 196           </p>
 197 <p>
 198             The macro should be used at global scope. <code class="computeroutput"><span class="identifier">namespace_seq</span></code>
 199             shall be the sequence of namespaces under which the following symbols
 200             will be defined:
 201           </p>
 202 <pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">tag</span>
 203 <span class="special">{</span>
 204     <span class="keyword">struct</span> <span class="identifier">name</span><span class="special">;</span>
 205 <span class="special">}</span>
 206
 207 <span class="keyword">namespace</span> <span class="identifier">expression</span>
 208 <span class="special">{</span>
 209     <span class="keyword">template</span> <span class="special">&lt;</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> <span class="keyword">typename</span> <span class="identifier">AN</span><span class="special">&gt;</span>
 210     <span class="keyword">struct</span> <span class="identifier">name</span>
 211         <span class="special">:</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">phoenix</span><span class="special">::</span><span class="identifier">expr</span><span class="special">&lt;</span>
 212             <span class="identifier">tag</span><span class="special">::</span><span class="identifier">name</span>
 213           <span class="special">,</span> <span class="identifier">A0</span>
 214           <span class="special">,</span> <span class="identifier">A1</span>
 215             <span class="special">...</span>
 216           <span class="special">,</span> <span class="identifier">AN</span>
 217         <span class="special">&gt;</span>
 218     <span class="special">{};</span>
 219 <span class="special">}</span>
 220
 221 <span class="keyword">namespace</span> <span class="identifier">rule</span>
 222 <span class="special">{</span>
 223     <span class="keyword">struct</span> <span class="identifier">name</span>
 224         <span class="special">:</span> <span class="identifier">expression</span><span class="special">::</span><span class="identifier">name</span><span class="special">&lt;</span>
 225             <span class="identifier">child_grammar0</span>
 226           <span class="special">,</span> <span class="identifier">child_grammar1</span>
 227             <span class="special">...</span>
 228           <span class="special">,</span> <span class="identifier">proto</span><span class="special">::</span><span class="identifier">vararg</span><span class="special">&lt;</span><span class="identifier">child_grammarN</span><span class="special">&gt;</span>
 229         <span class="special">&gt;</span>
 230     <span class="special">{};</span>
 231 <span class="special">}</span>
 232
 233 <span class="keyword">namespace</span> <span class="identifier">functional</span>
 234 <span class="special">{</span>
 235     <span class="keyword">struct</span> <span class="identifier">make_name</span><span class="special">;</span> <span class="comment">// A polymorphic function object that can be called to create the expression node</span>
 236 <span class="special">}</span>
 237
 238 <span class="keyword">namespace</span> <span class="identifier">result_of</span>
 239 <span class="special">{</span>
 240     <span class="keyword">template</span> <span class="special">&lt;</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> <span class="keyword">typename</span> <span class="identifier">AN</span><span class="special">&gt;</span>
 241     <span class="keyword">struct</span> <span class="identifier">make_name</span><span class="special">;</span> <span class="comment">// The result type of the expression node</span>
 242 <span class="special">}</span>
 243
 244 <span class="comment">// convenience polymorphic function to create an expression node</span>
 245 <span class="keyword">template</span> <span class="special">&lt;</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> <span class="keyword">typename</span> <span class="identifier">AN</span><span class="special">&gt;</span>
 246 <span class="identifier">result_of</span><span class="special">::</span><span class="identifier">make_name</span><span class="special">&lt;</span><span class="identifier">A0</span><span class="special">,</span> <span class="identifier">A1</span> <span class="special">...</span> <span class="identifier">AN</span><span class="special">&gt;</span>
 247 <span class="identifier">make_name</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> <span class="identifier">AN</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">an</span><span class="special">);</span>
 248 </pre>
 249 <p>
 250             This macros also adds a specialization for <code class="computeroutput"><span class="identifier">meta_grammar</span><span class="special">::</span><span class="identifier">case_</span><span class="special">&lt;</span><span class="identifier">tag</span><span class="special">::</span><span class="identifier">name</span><span class="special">&gt;</span></code> to enable the rule for further use
 251             in actions.
 252           </p>
 253 <h6>
 254 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_vararg.h3"></a>
 255             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_vararg.header"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_vararg.header">Header</a>
 256           </h6>
 257 <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">phoenix</span><span class="special">/</span><span class="identifier">core</span><span class="special">/</span><span class="identifier">expression</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
 258 </pre>
 259 <h6>
 260 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_vararg.h4"></a>
 261             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_vararg.example"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_vararg.example">Example</a>
 262           </h6>
 263 <pre class="programlisting"><span class="identifier">BOOST_PHOENIX_DEFINE_EXPRESSION_VARARG</span><span class="special">(</span>
 264     <span class="special">(</span><span class="identifier">boost</span><span class="special">)(</span><span class="identifier">phoenix</span><span class="special">)(</span><span class="identifier">mem_fun_ptr</span><span class="special">)</span>
 265   <span class="special">,</span> <span class="special">(</span><span class="identifier">meta_grammar</span><span class="special">)</span>                <span class="comment">// Pointer to Object</span>
 266     <span class="special">(</span><span class="identifier">meta_grammar</span><span class="special">)</span>                <span class="comment">// Member pointer</span>
 267     <span class="special">(</span><span class="identifier">meta_grammar</span><span class="special">)</span>                <span class="comment">// Variable number of arguments</span>
 268   <span class="special">,</span> <span class="identifier">BOOST_PHOENIX_LIMIT</span>
 269 <span class="special">)</span>
 270 </pre>
 271 <p>
 272             This defines the member function pointer operator expression as described
 273             in <a class="link" href="../../modules/operator.html" title="Operator">operators</a>.
 274           </p>
 275 </div>
 276 <div class="section">
 277 <div class="titlepage"><div><div><h5 class="title">
 278 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext"></a><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext" title="BOOST_PHOENIX_DEFINE_EXPRESSION_EXT">BOOST_PHOENIX_DEFINE_EXPRESSION_EXT</a>
 279 </h5></div></div></div>
 280 <h6>
 281 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext.h0"></a>
 282             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext.description"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext.description">Description</a>
 283           </h6>
 284 <p>
 285             <code class="computeroutput"><span class="identifier">BOOST_PHOENIX_DEFINE_EXPRESSION_EXT</span></code>
 286             is a macro that can be used to generate all the necessary boilerplate
 287             to create Phoenix Expressions
 288           </p>
 289 <h6>
 290 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext.h1"></a>
 291             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext.synopsis"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext.synopsis">Synopsis</a>
 292           </h6>
 293 <pre class="programlisting"><span class="identifier">BOOST_PHOENIX_DEFINE_EXPRESSION_EXT</span><span class="special">(</span>
 294     <span class="identifier">actor</span>
 295   <span class="special">,</span> <span class="special">(</span><span class="identifier">namespace_seq</span><span class="special">)(</span><span class="identifier">name</span><span class="special">)</span>
 296   <span class="special">,</span> <span class="special">(</span><span class="identifier">child_grammar0</span><span class="special">)</span>
 297     <span class="special">(</span><span class="identifier">child_grammar1</span><span class="special">)</span>
 298     <span class="special">...</span>
 299     <span class="special">(</span><span class="identifier">child_grammarN</span><span class="special">)</span>
 300   <span class="special">,</span> <span class="identifier">N</span>
 301 <span class="special">)</span>
 302 </pre>
 303 <h6>
 304 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext.h2"></a>
 305             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext.semantics"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext.semantics">Semantics</a>
 306           </h6>
 307 <p>
 308             The above macro generates the necessary code for an expression <code class="computeroutput"><span class="identifier">name</span></code> in namespace <code class="computeroutput"><span class="identifier">namespace_seq</span></code>.
 309             The sequence of <code class="computeroutput"><span class="special">(</span><span class="identifier">child_grammarN</span><span class="special">)</span></code> declares how many children the expression
 310             will have and what <code class="computeroutput"><span class="identifier">proto</span><span class="special">::</span><span class="identifier">grammar</span></code>
 311             they match.
 312           </p>
 313 <p>
 314             The macro should be used at global scope. <code class="computeroutput"><span class="identifier">namespace_seq</span></code>
 315             shall be the sequence of namespaces under which the following symbols
 316             will be defined:
 317           </p>
 318 <pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">tag</span>
 319 <span class="special">{</span>
 320     <span class="keyword">struct</span> <span class="identifier">name</span><span class="special">;</span>
 321 <span class="special">}</span>
 322
 323 <span class="keyword">namespace</span> <span class="identifier">expression</span>
 324 <span class="special">{</span>
 325     <span class="keyword">template</span> <span class="special">&lt;</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> <span class="keyword">typename</span> <span class="identifier">AN</span><span class="special">&gt;</span>
 326     <span class="keyword">struct</span> <span class="identifier">name</span>
 327         <span class="special">:</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">phoenix</span><span class="special">::</span><span class="identifier">expr_ext</span><span class="special">&lt;</span>
 328             <span class="identifier">actor</span>
 329           <span class="special">,</span> <span class="identifier">tag</span><span class="special">::</span><span class="identifier">name</span>
 330           <span class="special">,</span> <span class="identifier">A0</span>
 331           <span class="special">,</span> <span class="identifier">A1</span>
 332             <span class="special">...</span>
 333           <span class="special">,</span> <span class="identifier">AN</span>
 334         <span class="special">&gt;</span>
 335 <span class="special">}</span>
 336
 337 <span class="keyword">namespace</span> <span class="identifier">rule</span>
 338 <span class="special">{</span>
 339     <span class="keyword">struct</span> <span class="identifier">name</span>
 340         <span class="special">:</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">phoenix</span><span class="special">::</span><span class="identifier">expr</span><span class="special">&lt;</span>
 341             <span class="identifier">child_grammar0</span>
 342           <span class="special">,</span> <span class="identifier">child_grammar1</span>
 343             <span class="special">...</span>
 344           <span class="special">,</span> <span class="identifier">child_grammarN</span>
 345         <span class="special">&gt;</span>
 346     <span class="special">{};</span>
 347 <span class="special">}</span>
 348
 349 <span class="keyword">namespace</span> <span class="identifier">functional</span>
 350 <span class="special">{</span>
 351     <span class="keyword">struct</span> <span class="identifier">make_name</span><span class="special">;</span> <span class="comment">// A polymorphic function object that can be called to create the expression node</span>
 352 <span class="special">}</span>
 353
 354 <span class="keyword">namespace</span> <span class="identifier">result_of</span>
 355 <span class="special">{</span>
 356     <span class="keyword">template</span> <span class="special">&lt;</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> <span class="keyword">typename</span> <span class="identifier">AN</span><span class="special">&gt;</span>
 357     <span class="keyword">struct</span> <span class="identifier">make_name</span><span class="special">;</span> <span class="comment">// The result type of the expression node</span>
 358 <span class="special">}</span>
 359
 360 <span class="comment">// convenience polymorphic function to create an expression node</span>
 361 <span class="keyword">template</span> <span class="special">&lt;</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> <span class="keyword">typename</span> <span class="identifier">AN</span><span class="special">&gt;</span>
 362 <span class="identifier">result_of</span><span class="special">::</span><span class="identifier">make_name</span><span class="special">&lt;</span><span class="identifier">A0</span><span class="special">,</span> <span class="identifier">A1</span> <span class="special">...</span> <span class="identifier">AN</span><span class="special">&gt;</span>
 363 <span class="identifier">make_name</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> <span class="identifier">AN</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">an</span><span class="special">);</span>
 364 </pre>
 365 <p>
 366             This macros also adds a specialization for <code class="computeroutput"><span class="identifier">meta_grammar</span><span class="special">::</span><span class="identifier">case_</span><span class="special">&lt;</span><span class="identifier">tag</span><span class="special">::</span><span class="identifier">name</span><span class="special">&gt;</span></code> to enable the rule for further use
 367             in actions.
 368           </p>
 369 <h6>
 370 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext.h3"></a>
 371             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext.header"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext.header">Header</a>
 372           </h6>
 373 <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">phoenix</span><span class="special">/</span><span class="identifier">core</span><span class="special">/</span><span class="identifier">expression</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
 374 </pre>
 375 <h6>
 376 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext.h4"></a>
 377             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext.example"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext.example">Example</a>
 378           </h6>
 379 <pre class="programlisting"><span class="identifier">BOOST_PHOENIX_DEFINE_EXPRESSION_EXT</span><span class="special">(</span>
 380     <span class="identifier">if_actor</span>
 381   <span class="special">,</span> <span class="special">(</span><span class="identifier">boost</span><span class="special">)(</span><span class="identifier">phoenix</span><span class="special">)(</span><span class="identifier">if_</span><span class="special">)</span>
 382   <span class="special">,</span> <span class="special">(</span><span class="identifier">meta_grammar</span><span class="special">)</span> <span class="comment">// Cond</span>
 383     <span class="special">(</span><span class="identifier">meta_grammar</span><span class="special">)</span> <span class="comment">// Then</span>
 384 <span class="special">)</span>
 385 </pre>
 386 <p>
 387             This defines the if_ expression. The custom actor defines <code class="computeroutput"><span class="identifier">else_</span></code> as a member.
 388           </p>
 389 </div>
 390 <div class="section">
 391 <div class="titlepage"><div><div><h5 class="title">
 392 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext_vararg"></a><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext_vararg" title="BOOST_PHOENIX_DEFINE_EXPRESSION_EXT_VARARG">BOOST_PHOENIX_DEFINE_EXPRESSION_EXT_VARARG</a>
 393 </h5></div></div></div>
 394 <h6>
 395 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext_vararg.h0"></a>
 396             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext_vararg.description"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext_vararg.description">Description</a>
 397           </h6>
 398 <p>
 399             <code class="computeroutput"><span class="identifier">BOOST_PHOENIX_DEFINE_EXPRESSION_EXT_VARARG</span></code>
 400             is a macro that can be used to generate all the necessary boilerplate
 401             to create Phoenix Expressions
 402           </p>
 403 <h6>
 404 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext_vararg.h1"></a>
 405             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext_vararg.synopsis"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext_vararg.synopsis">Synopsis</a>
 406           </h6>
 407 <pre class="programlisting"><span class="identifier">BOOST_PHOENIX_DEFINE_EXPRESSION_EXT_VARARG</span><span class="special">(</span>
 408     <span class="identifier">actor</span>
 409   <span class="special">,</span> <span class="special">(</span><span class="identifier">namespace_seq</span><span class="special">)(</span><span class="identifier">name</span><span class="special">)</span>
 410   <span class="special">,</span> <span class="special">(</span><span class="identifier">child_grammar0</span><span class="special">)</span>
 411     <span class="special">(</span><span class="identifier">child_grammar1</span><span class="special">)</span>
 412     <span class="special">...</span>
 413     <span class="special">(</span><span class="identifier">child_grammarN</span><span class="special">)</span>
 414   <span class="special">,</span> <span class="identifier">N</span>
 415 <span class="special">)</span>
 416 </pre>
 417 <h6>
 418 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext_vararg.h2"></a>
 419             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext_vararg.semantics"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext_vararg.semantics">Semantics</a>
 420           </h6>
 421 <p>
 422             The above macro generates the necessary code for an expression <code class="computeroutput"><span class="identifier">name</span></code> in namespace <code class="computeroutput"><span class="identifier">namespace_seq</span></code>.
 423             <code class="computeroutput"><span class="identifier">N</span></code> is the maximum number
 424             of variable children. All but the last elements in the grammar sequence
 425             are required children of the expression, and the last denotes a variable
 426             number of children. The number of children an expression of this kind
 427             can hold is therefor <code class="computeroutput"><span class="identifier">N</span><span class="special">-</span><span class="number">1</span></code> plus
 428             the size of the sequence
 429           </p>
 430 <p>
 431             The macro should be used at global scope. <code class="computeroutput"><span class="identifier">namespace_seq</span></code>
 432             shall be the sequence of namespaces under which the following symbols
 433             will be defined:
 434           </p>
 435 <pre class="programlisting"><span class="keyword">namespace</span> <span class="identifier">tag</span>
 436 <span class="special">{</span>
 437     <span class="keyword">struct</span> <span class="identifier">name</span><span class="special">;</span>
 438 <span class="special">}</span>
 439
 440 <span class="keyword">namespace</span> <span class="identifier">expression</span>
 441 <span class="special">{</span>
 442     <span class="keyword">template</span> <span class="special">&lt;</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> <span class="keyword">typename</span> <span class="identifier">AN</span><span class="special">&gt;</span>
 443     <span class="keyword">struct</span> <span class="identifier">name</span>
 444         <span class="special">:</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">phoenix</span><span class="special">::</span><span class="identifier">expr_ext</span><span class="special">&lt;</span>
 445             <span class="identifier">actor</span>
 446           <span class="special">,</span> <span class="identifier">tag</span><span class="special">::</span><span class="identifier">name</span>
 447           <span class="special">,</span> <span class="identifier">A0</span>
 448           <span class="special">,</span> <span class="identifier">A1</span>
 449             <span class="special">...</span>
 450           <span class="special">,</span> <span class="identifier">AN</span>
 451         <span class="special">&gt;</span>
 452     <span class="special">{};</span>
 453 <span class="special">}</span>
 454
 455 <span class="keyword">namespace</span> <span class="identifier">rule</span>
 456 <span class="special">{</span>
 457     <span class="keyword">struct</span> <span class="identifier">name</span>
 458         <span class="special">:</span> <span class="identifier">expression</span><span class="special">::</span><span class="identifier">name</span><span class="special">&lt;</span>
 459             <span class="identifier">child_grammar0</span>
 460           <span class="special">,</span> <span class="identifier">child_grammar1</span>
 461             <span class="special">...</span>
 462           <span class="special">,</span> <span class="identifier">proto</span><span class="special">::</span><span class="identifier">vararg</span><span class="special">&lt;</span><span class="identifier">child_grammarN</span><span class="special">&gt;</span>
 463         <span class="special">&gt;</span>
 464     <span class="special">{};</span>
 465 <span class="special">}</span>
 466
 467 <span class="keyword">namespace</span> <span class="identifier">functional</span>
 468 <span class="special">{</span>
 469     <span class="keyword">struct</span> <span class="identifier">make_name</span><span class="special">;</span> <span class="comment">// A polymorphic function object that can be called to create the expression node</span>
 470 <span class="special">}</span>
 471
 472 <span class="keyword">namespace</span> <span class="identifier">result_of</span>
 473 <span class="special">{</span>
 474     <span class="keyword">template</span> <span class="special">&lt;</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> <span class="keyword">typename</span> <span class="identifier">AN</span><span class="special">&gt;</span>
 475     <span class="keyword">struct</span> <span class="identifier">make_name</span><span class="special">;</span> <span class="comment">// The result type of the expression node</span>
 476 <span class="special">}</span>
 477
 478 <span class="comment">// convenience polymorphic function to create an expression node</span>
 479 <span class="keyword">template</span> <span class="special">&lt;</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> <span class="keyword">typename</span> <span class="identifier">AN</span><span class="special">&gt;</span>
 480 <span class="identifier">result_of</span><span class="special">::</span><span class="identifier">make_name</span><span class="special">&lt;</span><span class="identifier">A0</span><span class="special">,</span> <span class="identifier">A1</span> <span class="special">...</span> <span class="identifier">AN</span><span class="special">&gt;</span>
 481 <span class="identifier">make_name</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> <span class="identifier">AN</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">an</span><span class="special">);</span>
 482 </pre>
 483 <p>
 484             This macros also adds a specialization for <code class="computeroutput"><span class="identifier">meta_grammar</span><span class="special">::</span><span class="identifier">case_</span><span class="special">&lt;</span><span class="identifier">tag</span><span class="special">::</span><span class="identifier">name</span><span class="special">&gt;</span></code> to enable the rule for further use
 485             in actions.
 486           </p>
 487 <h6>
 488 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext_vararg.h3"></a>
 489             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext_vararg.header"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext_vararg.header">Header</a>
 490           </h6>
 491 <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">phoenix</span><span class="special">/</span><span class="identifier">core</span><span class="special">/</span><span class="identifier">expression</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
 492 </pre>
 493 <h6>
 494 <a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext_vararg.h4"></a>
 495             <span class="phrase"><a name="phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext_vararg.example"></a></span><a class="link" href="boilerplate_macros.html#phoenix.inside.expression.boilerplate_macros.boost_phoenix_define_expression_ext_vararg.example">Example</a>
 496           </h6>
 497 <p>
 498             TBD
 499           </p>
 500 </div>
 501 </div>
 502 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 503 <td align="left"></td>
 504 <td align="right"><div class="copyright-footer">Copyright &#169; 2002-2005, 2010, 2014 Joel de Guzman, Dan Marsden, Thomas Heller, John
 505       Fletcher<p>
 506         Distributed under the Boost Software License, Version 1.0. (See accompanying
 507         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>)
 508       </p>
 509 </div></td>
 510 </tr></table>
 511 <hr>
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