libs/fusion/doc/html/fusion/view/transform_view.html

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  25 <div class="section">
  26 <div class="titlepage"><div><div><h3 class="title">
  27 <a name="fusion.view.transform_view"></a><a class="link" href="transform_view.html" title="transform_view">transform_view</a>
  28 </h3></div></div></div>
  29 <p>
  30         The unary version of <code class="computeroutput"><span class="identifier">transform_view</span></code>
  31         presents a view of its underlying sequence given a unary function object
  32         or function pointer. The binary version of <code class="computeroutput"><span class="identifier">transform_view</span></code>
  33         presents a view of 2 underlying sequences, given a binary function object
  34         or function pointer. The <code class="computeroutput"><span class="identifier">transform_view</span></code>
  35         inherits the traversal characteristics (see <a class="link" href="../sequence/concepts.html#fusion.sequence.concepts.traversal">Sequence
  36         Traversal Concept</a>) of its underlying sequence or sequences.
  37       </p>
  38 <h5>
  39 <a name="fusion.view.transform_view.h0"></a>
  40         <span class="phrase"><a name="fusion.view.transform_view.header"></a></span><a class="link" href="transform_view.html#fusion.view.transform_view.header">Header</a>
  41       </h5>
  42 <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">fusion</span><span class="special">/</span><span class="identifier">view</span><span class="special">/</span><span class="identifier">transform_view</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
  43 <span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">fusion</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">transform_view</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
  44 </pre>
  45 <h5>
  46 <a name="fusion.view.transform_view.h1"></a>
  47         <span class="phrase"><a name="fusion.view.transform_view.synopsis"></a></span><a class="link" href="transform_view.html#fusion.view.transform_view.synopsis">Synopsis</a>
  48       </h5>
  49 <p>
  50         <span class="bold"><strong>Unary Version</strong></span>
  51       </p>
  52 <pre class="programlisting"><span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Sequence</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">F1</span><span class="special">&gt;</span>
  53 <span class="keyword">struct</span> <span class="identifier">transform_view</span><span class="special">;</span>
  54 </pre>
  55 <p>
  56         <span class="bold"><strong>Binary Version</strong></span>
  57       </p>
  58 <pre class="programlisting"><span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Sequence1</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Sequence2</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">F2</span><span class="special">&gt;</span>
  59 <span class="keyword">struct</span> <span class="identifier">transform_view</span><span class="special">;</span>
  60 </pre>
  61 <h5>
  62 <a name="fusion.view.transform_view.h2"></a>
  63         <span class="phrase"><a name="fusion.view.transform_view.template_parameters"></a></span><a class="link" href="transform_view.html#fusion.view.transform_view.template_parameters">Template
  64         parameters</a>
  65       </h5>
  66 <div class="informaltable"><table class="table">
  67 <colgroup>
  68 <col>
  69 <col>
  70 <col>
  71 </colgroup>
  72 <thead><tr>
  73 <th>
  74                 <p>
  75                   Parameter
  76                 </p>
  77               </th>
  78 <th>
  79                 <p>
  80                   Description
  81                 </p>
  82               </th>
  83 <th>
  84                 <p>
  85                   Default
  86                 </p>
  87               </th>
  88 </tr></thead>
  89 <tbody>
  90 <tr>
  91 <td>
  92                 <p>
  93                   <code class="computeroutput"><span class="identifier">Sequence</span></code>
  94                 </p>
  95               </td>
  96 <td>
  97                 <p>
  98                   A <a class="link" href="../sequence/concepts/forward_sequence.html" title="Forward Sequence">Forward
  99                   Sequence</a>
 100                 </p>
 101               </td>
 102 <td>
 103               </td>
 104 </tr>
 105 <tr>
 106 <td>
 107                 <p>
 108                   <code class="computeroutput"><span class="identifier">Sequence1</span></code>
 109                 </p>
 110               </td>
 111 <td>
 112                 <p>
 113                   A <a class="link" href="../sequence/concepts/forward_sequence.html" title="Forward Sequence">Forward
 114                   Sequence</a>
 115                 </p>
 116               </td>
 117 <td>
 118               </td>
 119 </tr>
 120 <tr>
 121 <td>
 122                 <p>
 123                   <code class="computeroutput"><span class="identifier">Sequence2</span></code>
 124                 </p>
 125               </td>
 126 <td>
 127                 <p>
 128                   A <a class="link" href="../sequence/concepts/forward_sequence.html" title="Forward Sequence">Forward
 129                   Sequence</a>
 130                 </p>
 131               </td>
 132 <td>
 133               </td>
 134 </tr>
 135 <tr>
 136 <td>
 137                 <p>
 138                   <code class="computeroutput"><span class="identifier">F1</span></code>
 139                 </p>
 140               </td>
 141 <td>
 142                 <p>
 143                   A unary function object or function pointer. <code class="computeroutput"><a href="http://www.boost.org/libs/utility/utility.htm#result_of" target="_top"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">result_of</span></code></a><span class="special">&lt;</span><span class="identifier">F1</span><span class="special">(</span><span class="identifier">E</span><span class="special">)&gt;::</span><span class="identifier">type</span></code> is the return type of an
 144                   instance of <code class="computeroutput"><span class="identifier">F1</span></code>
 145                   when called with a value of each element type <code class="computeroutput"><span class="identifier">E</span></code>
 146                   in the input sequence.
 147                 </p>
 148               </td>
 149 <td>
 150               </td>
 151 </tr>
 152 <tr>
 153 <td>
 154                 <p>
 155                   <code class="computeroutput"><span class="identifier">F2</span></code>
 156                 </p>
 157               </td>
 158 <td>
 159                 <p>
 160                   A binary function object or function pointer. <code class="computeroutput"><a href="http://www.boost.org/libs/utility/utility.htm#result_of" target="_top"><code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">result_of</span></code></a><span class="special">&lt;</span><span class="identifier">F2</span><span class="special">(</span><span class="identifier">E1</span><span class="special">,</span>
 161                   <span class="identifier">E2</span><span class="special">)&gt;::</span><span class="identifier">type</span></code> is the return type of an
 162                   instance of <code class="computeroutput"><span class="identifier">F2</span></code>
 163                   when called with a value of each corresponding pair of element
 164                   type <code class="computeroutput"><span class="identifier">E1</span></code> and <code class="computeroutput"><span class="identifier">E2</span></code> in the input sequences.
 165                 </p>
 166               </td>
 167 <td>
 168               </td>
 169 </tr>
 170 </tbody>
 171 </table></div>
 172 <h5>
 173 <a name="fusion.view.transform_view.h3"></a>
 174         <span class="phrase"><a name="fusion.view.transform_view.model_of"></a></span><a class="link" href="transform_view.html#fusion.view.transform_view.model_of">Model
 175         of</a>
 176       </h5>
 177 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem">
 178             <a class="link" href="../sequence/concepts/forward_sequence.html" title="Forward Sequence">Forward Sequence</a>,
 179             <a class="link" href="../sequence/concepts/bidirectional_sequence.html" title="Bidirectional Sequence">Bidirectional
 180             Sequence</a> or <a class="link" href="../sequence/concepts/random_access_sequence.html" title="Random Access Sequence">Random
 181             Access Sequence</a> depending on the traversal characteristics (see
 182             <a class="link" href="../sequence/concepts.html#fusion.sequence.concepts.traversal">Sequence Traversal
 183             Concept</a>) of its underlying sequence.
 184           </li></ul></div>
 185 <div class="variablelist">
 186 <p class="title"><b>Notation</b></p>
 187 <dl class="variablelist">
 188 <dt><span class="term"><code class="computeroutput"><span class="identifier">TV</span></code></span></dt>
 189 <dd><p>
 190               A <code class="computeroutput"><span class="identifier">transform_view</span></code> type
 191             </p></dd>
 192 <dt><span class="term"><code class="computeroutput"><span class="identifier">BTV</span></code></span></dt>
 193 <dd><p>
 194               A binary <code class="computeroutput"><span class="identifier">transform_view</span></code>
 195               type
 196             </p></dd>
 197 <dt><span class="term"><code class="computeroutput"><span class="identifier">UTV</span></code></span></dt>
 198 <dd><p>
 199               A unary <code class="computeroutput"><span class="identifier">transform_view</span></code>
 200               type
 201             </p></dd>
 202 <dt><span class="term"><code class="computeroutput"><span class="identifier">f1</span></code></span></dt>
 203 <dd><p>
 204               An instance of <code class="computeroutput"><span class="identifier">F1</span></code>
 205             </p></dd>
 206 <dt><span class="term"><code class="computeroutput"><span class="identifier">f2</span></code></span></dt>
 207 <dd><p>
 208               An instance of <code class="computeroutput"><span class="identifier">F2</span></code>
 209             </p></dd>
 210 <dt><span class="term"><code class="computeroutput"><span class="identifier">s</span></code></span></dt>
 211 <dd><p>
 212               An instance of <code class="computeroutput"><span class="identifier">Sequence</span></code>
 213             </p></dd>
 214 <dt><span class="term"><code class="computeroutput"><span class="identifier">s1</span></code></span></dt>
 215 <dd><p>
 216               An instance of <code class="computeroutput"><span class="identifier">Sequence1</span></code>
 217             </p></dd>
 218 <dt><span class="term"><code class="computeroutput"><span class="identifier">s2</span></code></span></dt>
 219 <dd><p>
 220               An instance of <code class="computeroutput"><span class="identifier">Sequence2</span></code>
 221             </p></dd>
 222 <dt><span class="term"><code class="computeroutput"><span class="identifier">tv</span></code>, <code class="computeroutput"><span class="identifier">tv2</span></code></span></dt>
 223 <dd><p>
 224               Instances of <code class="computeroutput"><span class="identifier">transform_view</span></code>
 225             </p></dd>
 226 </dl>
 227 </div>
 228 <h5>
 229 <a name="fusion.view.transform_view.h4"></a>
 230         <span class="phrase"><a name="fusion.view.transform_view.expression_semantics"></a></span><a class="link" href="transform_view.html#fusion.view.transform_view.expression_semantics">Expression
 231         Semantics</a>
 232       </h5>
 233 <p>
 234         Semantics of an expression is defined only where it differs from, or is not
 235         defined in <a class="link" href="../sequence/concepts/forward_sequence.html" title="Forward Sequence">Forward
 236         Sequence</a>, <a class="link" href="../sequence/concepts/bidirectional_sequence.html" title="Bidirectional Sequence">Bidirectional
 237         Sequence</a> or <a class="link" href="../sequence/concepts/random_access_sequence.html" title="Random Access Sequence">Random
 238         Access Sequence</a> depending on the traversal characteristics (see <a class="link" href="../sequence/concepts.html#fusion.sequence.concepts.traversal">Sequence Traversal Concept</a>)
 239         of its underlying sequence or sequences.
 240       </p>
 241 <div class="informaltable"><table class="table">
 242 <colgroup>
 243 <col>
 244 <col>
 245 </colgroup>
 246 <thead><tr>
 247 <th>
 248                 <p>
 249                   Expression
 250                 </p>
 251               </th>
 252 <th>
 253                 <p>
 254                   Semantics
 255                 </p>
 256               </th>
 257 </tr></thead>
 258 <tbody>
 259 <tr>
 260 <td>
 261                 <p>
 262                   <code class="computeroutput"><span class="identifier">UTV</span><span class="special">(</span><span class="identifier">s</span><span class="special">,</span>
 263                   <span class="identifier">f1</span><span class="special">)</span></code>
 264                 </p>
 265               </td>
 266 <td>
 267                 <p>
 268                   Creates a unary <code class="computeroutput"><span class="identifier">transform_view</span></code>
 269                   given sequence, <code class="computeroutput"><span class="identifier">s</span></code>
 270                   and unary function object or function pointer, <code class="computeroutput"><span class="identifier">f1</span></code>.
 271                 </p>
 272               </td>
 273 </tr>
 274 <tr>
 275 <td>
 276                 <p>
 277                   <code class="computeroutput"><span class="identifier">BTV</span><span class="special">(</span><span class="identifier">s1</span><span class="special">,</span>
 278                   <span class="identifier">s2</span><span class="special">,</span>
 279                   <span class="identifier">f2</span><span class="special">)</span></code>
 280                 </p>
 281               </td>
 282 <td>
 283                 <p>
 284                   Creates a binary <code class="computeroutput"><span class="identifier">transform_view</span></code>
 285                   given sequences, <code class="computeroutput"><span class="identifier">s1</span></code>
 286                   and <code class="computeroutput"><span class="identifier">s2</span></code> and binary
 287                   function object or function pointer, <code class="computeroutput"><span class="identifier">f2</span></code>.
 288                 </p>
 289               </td>
 290 </tr>
 291 <tr>
 292 <td>
 293                 <p>
 294                   <code class="computeroutput"><span class="identifier">TV</span><span class="special">(</span><span class="identifier">tv</span><span class="special">)</span></code>
 295                 </p>
 296               </td>
 297 <td>
 298                 <p>
 299                   Copy constructs a <code class="computeroutput"><span class="identifier">transform_view</span></code>
 300                   from another <code class="computeroutput"><span class="identifier">transform_view</span></code>,
 301                   <code class="computeroutput"><span class="identifier">tv</span></code>.
 302                 </p>
 303               </td>
 304 </tr>
 305 <tr>
 306 <td>
 307                 <p>
 308                   <code class="computeroutput"><span class="identifier">tv</span> <span class="special">=</span>
 309                   <span class="identifier">tv2</span></code>
 310                 </p>
 311               </td>
 312 <td>
 313                 <p>
 314                   Assigns to a <code class="computeroutput"><span class="identifier">transform_view</span></code>,
 315                   <code class="computeroutput"><span class="identifier">tv</span></code>, from another
 316                   <code class="computeroutput"><span class="identifier">transform_view</span></code>,
 317                   <code class="computeroutput"><span class="identifier">tv2</span></code>.
 318                 </p>
 319               </td>
 320 </tr>
 321 </tbody>
 322 </table></div>
 323 <h5>
 324 <a name="fusion.view.transform_view.h5"></a>
 325         <span class="phrase"><a name="fusion.view.transform_view.example"></a></span><a class="link" href="transform_view.html#fusion.view.transform_view.example">Example</a>
 326       </h5>
 327 <pre class="programlisting"><span class="keyword">struct</span> <span class="identifier">square</span>
 328 <span class="special">{</span>
 329     <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Sig</span><span class="special">&gt;</span>
 330     <span class="keyword">struct</span> <span class="identifier">result</span><span class="special">;</span>
 331
 332     <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">U</span><span class="special">&gt;</span>
 333     <span class="keyword">struct</span> <span class="identifier">result</span><span class="special">&lt;</span><span class="identifier">square</span><span class="special">(</span><span class="identifier">U</span><span class="special">)&gt;</span>
 334     <span class="special">:</span> <span class="identifier">remove_reference</span><span class="special">&lt;</span><span class="identifier">U</span><span class="special">&gt;</span>
 335     <span class="special">{};</span>
 336
 337     <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">T</span><span class="special">&gt;</span>
 338     <span class="identifier">T</span> <span class="keyword">operator</span><span class="special">()(</span><span class="identifier">T</span> <span class="identifier">x</span><span class="special">)</span> <span class="keyword">const</span>
 339     <span class="special">{</span>
 340         <span class="keyword">return</span> <span class="identifier">x</span> <span class="special">*</span> <span class="identifier">x</span><span class="special">;</span>
 341     <span class="special">}</span>
 342 <span class="special">};</span>
 343
 344 <span class="keyword">typedef</span> <a class="link" href="../container/vector.html" title="vector"><code class="computeroutput"><span class="identifier">vector</span></code></a><span class="special">&lt;</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">short</span><span class="special">,</span> <span class="keyword">double</span><span class="special">&gt;</span> <span class="identifier">vector_type</span><span class="special">;</span>
 345 <span class="identifier">vector_type</span> <span class="identifier">vec</span><span class="special">(</span><span class="number">2</span><span class="special">,</span> <span class="number">5</span><span class="special">,</span> <span class="number">3.3</span><span class="special">);</span>
 346
 347 <span class="identifier">transform_view</span><span class="special">&lt;</span><span class="identifier">vector_type</span><span class="special">,</span> <span class="identifier">square</span><span class="special">&gt;</span> <span class="identifier">transform</span><span class="special">(</span><span class="identifier">vec</span><span class="special">,</span> <span class="identifier">square</span><span class="special">());</span>
 348 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="identifier">transform</span> <span class="special">&lt;&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span>
 349 </pre>
 350 </div>
 351 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 352 <td align="left"></td>
 353 <td align="right"><div class="copyright-footer">Copyright &#169; 2001-2006, 2011, 2012 Joel de Guzman,
 354       Dan Marsden, Tobias Schwinger<p>
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