1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Boilerplate Macros</title> 5<link rel="stylesheet" href="../../../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../../index.html" title="Chapter 1. Phoenix 3.2.0"> 8<link rel="up" href="../expression.html" title="Phoenix Expressions"> 9<link rel="prev" href="../expression.html" title="Phoenix Expressions"> 10<link rel="next" href="../actions.html" title="More on Actions"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="../expression.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../expression.html"><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="../actions.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 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"><</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">></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"><</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">></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"><</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">></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"><</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">></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"><</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">></span> 124<span class="identifier">result_of</span><span class="special">::</span><span class="identifier">make_name</span><span class="special"><</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">></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">&</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> <span class="identifier">AN</span> <span class="keyword">const</span> <span class="special">&</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"><</span><span class="identifier">tag</span><span class="special">::</span><span class="identifier">name</span><span class="special">></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"><</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">></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"><</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">></span> 151<span class="keyword">typename</span> <span class="identifier">plus</span><span class="special"><</span><span class="identifier">Lhs</span><span class="special">,</span> <span class="identifier">Rhs</span><span class="special">>::</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">&</span> <span class="identifier">lhs</span><span class="special">,</span> <span class="identifier">Rhs</span> <span class="keyword">const</span> <span class="special">&</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"><</span><span class="identifier">Lhs</span><span class="special">,</span> <span class="identifier">Rhs</span><span class="special">>::</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"><</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">></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"><</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">></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"><</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"><</span><span class="identifier">child_grammarN</span><span class="special">></span> 229 <span class="special">></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"><</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">></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"><</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">></span> 246<span class="identifier">result_of</span><span class="special">::</span><span class="identifier">make_name</span><span class="special"><</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">></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">&</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> <span class="identifier">AN</span> <span class="keyword">const</span> <span class="special">&</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"><</span><span class="identifier">tag</span><span class="special">::</span><span class="identifier">name</span><span class="special">></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"><</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">></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"><</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">></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"><</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">></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"><</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">></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"><</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">></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"><</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">></span> 362<span class="identifier">result_of</span><span class="special">::</span><span class="identifier">make_name</span><span class="special"><</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">></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">&</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> <span class="identifier">AN</span> <span class="keyword">const</span> <span class="special">&</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"><</span><span class="identifier">tag</span><span class="special">::</span><span class="identifier">name</span><span class="special">></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"><</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">></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"><</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">></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"><</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">></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"><</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"><</span><span class="identifier">child_grammarN</span><span class="special">></span> 463 <span class="special">></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"><</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">></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"><</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">></span> 480<span class="identifier">result_of</span><span class="special">::</span><span class="identifier">make_name</span><span class="special"><</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">></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">&</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> <span class="identifier">AN</span> <span class="keyword">const</span> <span class="special">&</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"><</span><span class="identifier">tag</span><span class="special">::</span><span class="identifier">name</span><span class="special">></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"><</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">></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 © 2002-2005, 2010, 2014, 2015 Joel de Guzman, Dan Marsden, Thomas 505 Heller, John 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> 512<div class="spirit-nav"> 513<a accesskey="p" href="../expression.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../expression.html"><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="../actions.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 514</div> 515</body> 516</html> 517
