1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Symbols Generator (symbols)</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="Spirit 2.5.8"> 8<link rel="up" href="../string.html" title="String Generators"> 9<link rel="prev" href="string.html" title="String Generators (string, lit)"> 10<link rel="next" href="../../performance_measurements.html" title="Performance Measurements"> 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="string.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../string.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="../../performance_measurements.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h5 class="title"> 27<a name="spirit.karma.reference.string.symbols"></a><a class="link" href="symbols.html" title="Symbols Generator (symbols)">Symbols Generator 28 (<code class="computeroutput"><span class="identifier">symbols</span></code>)</a> 29</h5></div></div></div> 30<h6> 31<a name="spirit.karma.reference.string.symbols.h0"></a> 32 <span class="phrase"><a name="spirit.karma.reference.string.symbols.description"></a></span><a class="link" href="symbols.html#spirit.karma.reference.string.symbols.description">Description</a> 33 </h6> 34<p> 35 The class <code class="computeroutput"><span class="identifier">symbols</span></code> implements 36 an 'inverse' symbol table: an associative container (or map) of key-value 37 pairs where the values are (most of the time) strings. It maps the value 38 to be generated (the key) to any other value which will be emitted instead 39 of the original key. 40 </p> 41<p> 42 The Karma symbol table class <code class="computeroutput"><span class="identifier">symbols</span></code> 43 is-a generator, an instance of which may be used anywhere in the grammar 44 specification. It is an example of a dynamic generator. A dynamic generator 45 is characterized by its ability to modify its behavior at run time. Initially, 46 an empty symbols object will emit nothing. At any time, symbols may be 47 added, thus, dynamically altering its behavior. 48 </p> 49<h6> 50<a name="spirit.karma.reference.string.symbols.h1"></a> 51 <span class="phrase"><a name="spirit.karma.reference.string.symbols.header"></a></span><a class="link" href="symbols.html#spirit.karma.reference.string.symbols.header">Header</a> 52 </h6> 53<pre class="programlisting"><span class="comment">// forwards to <boost/spirit/home/karma/string/symbols.hpp></span> 54<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">spirit</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">karma_symbols</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 55</pre> 56<p> 57 Also, see <a class="link" href="../../../structure/include.html" title="Include">Include Structure</a>. 58 </p> 59<h6> 60<a name="spirit.karma.reference.string.symbols.h2"></a> 61 <span class="phrase"><a name="spirit.karma.reference.string.symbols.namespace"></a></span><a class="link" href="symbols.html#spirit.karma.reference.string.symbols.namespace">Namespace</a> 62 </h6> 63<div class="informaltable"><table class="table"> 64<colgroup><col></colgroup> 65<thead><tr><th> 66 <p> 67 Name 68 </p> 69 </th></tr></thead> 70<tbody><tr><td> 71 <p> 72 <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">karma</span><span class="special">::</span><span class="identifier">symbols</span></code> 73 </p> 74 </td></tr></tbody> 75</table></div> 76<h6> 77<a name="spirit.karma.reference.string.symbols.h3"></a> 78 <span class="phrase"><a name="spirit.karma.reference.string.symbols.synopsis"></a></span><a class="link" href="symbols.html#spirit.karma.reference.string.symbols.synopsis">Synopsis</a> 79 </h6> 80<pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Attrib</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">T</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Lookup</span> 81 <span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">CharEncoding</span><span class="special">,</span> <span class="keyword">typename</span> <span class="identifier">Tag</span><span class="special">></span> 82<span class="keyword">struct</span> <span class="identifier">symbols</span><span class="special">;</span> 83</pre> 84<h6> 85<a name="spirit.karma.reference.string.symbols.h4"></a> 86 <span class="phrase"><a name="spirit.karma.reference.string.symbols.template_parameters"></a></span><a class="link" href="symbols.html#spirit.karma.reference.string.symbols.template_parameters">Template 87 parameters</a> 88 </h6> 89<div class="informaltable"><table class="table"> 90<colgroup> 91<col> 92<col> 93<col> 94</colgroup> 95<thead><tr> 96<th> 97 <p> 98 Parameter 99 </p> 100 </th> 101<th> 102 <p> 103 Description 104 </p> 105 </th> 106<th> 107 <p> 108 Default 109 </p> 110 </th> 111</tr></thead> 112<tbody> 113<tr> 114<td> 115 <p> 116 <code class="computeroutput"><span class="identifier">Attrib</span></code> 117 </p> 118 </td> 119<td> 120 <p> 121 The type of the original attribute to be used as the key into 122 the symbol generator (the symbol). 123 </p> 124 </td> 125<td> 126 <p> 127 <code class="computeroutput"><span class="keyword">char</span></code> 128 </p> 129 </td> 130</tr> 131<tr> 132<td> 133 <p> 134 <code class="computeroutput"><span class="identifier">T</span></code> 135 </p> 136 </td> 137<td> 138 <p> 139 The data type associated with each key. 140 </p> 141 </td> 142<td> 143 <p> 144 <code class="computeroutput"><span class="identifier">unused_type</span></code> 145 </p> 146 </td> 147</tr> 148<tr> 149<td> 150 <p> 151 <code class="computeroutput"><span class="identifier">Lookup</span></code> 152 </p> 153 </td> 154<td> 155 <p> 156 The symbol search implementation 157 </p> 158 </td> 159<td> 160 <p> 161 if T is <code class="computeroutput"><span class="identifier">unused_type</span></code>, 162 <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">set</span><span class="special"><</span><span class="identifier">Attrib</span><span class="special">></span></code>, 163 and <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><</span><span class="identifier">Attrib</span><span class="special">,</span> 164 <span class="identifier">T</span><span class="special">></span></code> 165 otherwise 166 </p> 167 </td> 168</tr> 169<tr> 170<td> 171 <p> 172 <code class="computeroutput"><span class="identifier">CharEncoding</span></code> 173 </p> 174 </td> 175<td> 176 <p> 177 Used for character set selection, normally not used by end 178 user. 179 </p> 180 </td> 181<td> 182 <p> 183 <code class="computeroutput"><span class="identifier">unused_type</span></code> 184 </p> 185 </td> 186</tr> 187<tr> 188<td> 189 <p> 190 <code class="computeroutput"><span class="identifier">Tag</span></code> 191 </p> 192 </td> 193<td> 194 <p> 195 Used for character set selection, normally not used by end 196 user. 197 </p> 198 </td> 199<td> 200 <p> 201 <code class="computeroutput"><span class="identifier">unused_type</span></code> 202 </p> 203 </td> 204</tr> 205</tbody> 206</table></div> 207<h6> 208<a name="spirit.karma.reference.string.symbols.h5"></a> 209 <span class="phrase"><a name="spirit.karma.reference.string.symbols.model_of"></a></span><a class="link" href="symbols.html#spirit.karma.reference.string.symbols.model_of">Model 210 of</a> 211 </h6> 212<div class="blockquote"><blockquote class="blockquote"><p> 213 <a class="link" href="../generator_concepts/primitivegenerator.html" title="PrimitiveGenerator"><code class="computeroutput"><span class="identifier">PrimitiveGenerator</span></code></a> 214 </p></blockquote></div> 215<div class="variablelist"> 216<p class="title"><b>Notation</b></p> 217<dl class="variablelist"> 218<dt><span class="term"><code class="computeroutput"><span class="identifier">Sym</span></code></span></dt> 219<dd><p> 220 A <code class="computeroutput"><span class="identifier">symbols</span></code> type. 221 </p></dd> 222<dt><span class="term"><code class="computeroutput"><span class="identifier">Attrib</span></code></span></dt> 223<dd><p> 224 An attribute type. 225 </p></dd> 226<dt><span class="term"><code class="computeroutput"><span class="identifier">T</span></code></span></dt> 227<dd><p> 228 A data type. 229 </p></dd> 230<dt><span class="term"><code class="computeroutput"><span class="identifier">sym</span></code>, <code class="computeroutput"><span class="identifier">sym2</span></code></span></dt> 231<dd><p> 232 <code class="computeroutput"><span class="identifier">symbols</span></code> objects. 233 </p></dd> 234<dt><span class="term"><code class="computeroutput"><span class="identifier">sseq</span></code></span></dt> 235<dd><p> 236 An <a href="https://en.wikipedia.org/wiki/Standard_Template_Library" target="_top">STL</a> 237 container of strings. 238 </p></dd> 239<dt><span class="term"><code class="computeroutput"><span class="identifier">dseq</span></code></span></dt> 240<dd><p> 241 An <a href="https://en.wikipedia.org/wiki/Standard_Template_Library" target="_top">STL</a> 242 container of data with <code class="computeroutput"><span class="identifier">value_type</span></code> 243 <code class="computeroutput"><span class="identifier">T</span></code>. 244 </p></dd> 245<dt><span class="term"><code class="computeroutput"><span class="identifier">s1</span></code>...<code class="computeroutput"><span class="identifier">sN</span></code></span></dt> 246<dd><p> 247 A <a class="link" href="../../../qi/reference/basics.html#spirit.qi.reference.basics.string">String</a>. 248 </p></dd> 249<dt><span class="term"><code class="computeroutput"><span class="identifier">d1</span></code>...<code class="computeroutput"><span class="identifier">dN</span></code></span></dt> 250<dd><p> 251 Objects of type <code class="computeroutput"><span class="identifier">T</span></code>. 252 </p></dd> 253<dt><span class="term"><code class="computeroutput"><span class="identifier">f</span></code></span></dt> 254<dd><p> 255 A callable function or function object. 256 </p></dd> 257<dt><span class="term"><code class="computeroutput"><span class="identifier">f</span></code>, <code class="computeroutput"><span class="identifier">l</span></code></span></dt> 258<dd><p> 259 <code class="computeroutput"><span class="identifier">ForwardIterator</span></code> 260 first/last pair. 261 </p></dd> 262</dl> 263</div> 264<h6> 265<a name="spirit.karma.reference.string.symbols.h6"></a> 266 <span class="phrase"><a name="spirit.karma.reference.string.symbols.expression_semantics"></a></span><a class="link" href="symbols.html#spirit.karma.reference.string.symbols.expression_semantics">Expression 267 Semantics</a> 268 </h6> 269<p> 270 Semantics of an expression is defined only where it differs from, or 271 is not defined in <a class="link" href="../generator_concepts/primitivegenerator.html" title="PrimitiveGenerator"><code class="computeroutput"><span class="identifier">PrimitiveGenerator</span></code></a>. 272 </p> 273<div class="informaltable"><table class="table"> 274<colgroup> 275<col> 276<col> 277</colgroup> 278<thead><tr> 279<th> 280 <p> 281 Expression 282 </p> 283 </th> 284<th> 285 <p> 286 Semantics 287 </p> 288 </th> 289</tr></thead> 290<tbody> 291<tr> 292<td> 293 <p> 294 <code class="computeroutput"><span class="identifier">Sym</span><span class="special">()</span></code> 295 </p> 296 </td> 297<td> 298 <p> 299 Construct an empty symbols object instance named <code class="computeroutput"><span class="string">"symbols"</span></code>. 300 </p> 301 </td> 302</tr> 303<tr> 304<td> 305 <p> 306 <code class="computeroutput"><span class="identifier">Sym</span><span class="special">(</span><span class="identifier">name</span><span class="special">)</span></code> 307 </p> 308 </td> 309<td> 310 <p> 311 Construct an empty symbols object instance named <code class="computeroutput"><span class="identifier">name</span></code>. 312 </p> 313 </td> 314</tr> 315<tr> 316<td> 317 <p> 318 <code class="computeroutput"><span class="identifier">Sym</span><span class="special">(</span><span class="identifier">sym2</span><span class="special">)</span></code> 319 </p> 320 </td> 321<td> 322 <p> 323 Copy construct a symbols from <code class="computeroutput"><span class="identifier">sym2</span></code> 324 (Another <code class="computeroutput"><span class="identifier">symbols</span></code> 325 object). 326 </p> 327 </td> 328</tr> 329<tr> 330<td> 331 <p> 332 <code class="computeroutput"><span class="identifier">Sym</span><span class="special">(</span><span class="identifier">sseq</span><span class="special">)</span></code> 333 </p> 334 </td> 335<td> 336 <p> 337 Construct symbols from <code class="computeroutput"><span class="identifier">sseq</span></code> 338 (An <a href="https://en.wikipedia.org/wiki/Standard_Template_Library" target="_top">STL</a> 339 container of symbols of type <code class="computeroutput"><span class="identifier">Attrib</span></code>) 340 named <code class="computeroutput"><span class="string">"symbols"</span></code>. 341 </p> 342 </td> 343</tr> 344<tr> 345<td> 346 <p> 347 <code class="computeroutput"><span class="identifier">Sym</span><span class="special">(</span><span class="identifier">sseq</span><span class="special">,</span> 348 <span class="identifier">name</span><span class="special">)</span></code> 349 </p> 350 </td> 351<td> 352 <p> 353 Construct symbols from <code class="computeroutput"><span class="identifier">sseq</span></code> 354 (an <a href="https://en.wikipedia.org/wiki/Standard_Template_Library" target="_top">STL</a> 355 container of symbols of type <code class="computeroutput"><span class="identifier">Attrib</span></code>) 356 named <code class="computeroutput"><span class="identifier">name</span></code>. 357 </p> 358 </td> 359</tr> 360<tr> 361<td> 362 <p> 363 <code class="computeroutput"><span class="identifier">Sym</span><span class="special">(</span><span class="identifier">sseq</span><span class="special">,</span> 364 <span class="identifier">dseq</span><span class="special">)</span></code> 365 </p> 366 </td> 367<td> 368 <p> 369 Construct symbols from <code class="computeroutput"><span class="identifier">sseq</span></code> 370 and <code class="computeroutput"><span class="identifier">dseq</span></code> (An 371 <a href="https://en.wikipedia.org/wiki/Standard_Template_Library" target="_top">STL</a> 372 container of symbols of type <code class="computeroutput"><span class="identifier">Attrib</span></code> 373 and an <a href="https://en.wikipedia.org/wiki/Standard_Template_Library" target="_top">STL</a> 374 container of data with <code class="computeroutput"><span class="identifier">value_type</span></code> 375 <code class="computeroutput"><span class="identifier">T</span></code>) which is 376 named <code class="computeroutput"><span class="string">"symbols"</span></code>. 377 </p> 378 </td> 379</tr> 380<tr> 381<td> 382 <p> 383 <code class="computeroutput"><span class="identifier">Sym</span><span class="special">(</span><span class="identifier">sseq</span><span class="special">,</span> 384 <span class="identifier">dseq</span><span class="special">,</span> 385 <span class="identifier">name</span><span class="special">)</span></code> 386 </p> 387 </td> 388<td> 389 <p> 390 Construct symbols from <code class="computeroutput"><span class="identifier">sseq</span></code> 391 and <code class="computeroutput"><span class="identifier">dseq</span></code> (An 392 <a href="https://en.wikipedia.org/wiki/Standard_Template_Library" target="_top">STL</a> 393 container of symbols of type <code class="computeroutput"><span class="identifier">Attrib</span></code> 394 and an <a href="https://en.wikipedia.org/wiki/Standard_Template_Library" target="_top">STL</a> 395 container of data with <code class="computeroutput"><span class="identifier">value_type</span></code> 396 <code class="computeroutput"><span class="identifier">T</span></code>) which is 397 named <code class="computeroutput"><span class="identifier">name</span></code>. 398 </p> 399 </td> 400</tr> 401<tr> 402<td> 403 <p> 404 <code class="computeroutput"><span class="identifier">sym</span> <span class="special">=</span> 405 <span class="identifier">sym2</span></code> 406 </p> 407 </td> 408<td> 409 <p> 410 Assign <code class="computeroutput"><span class="identifier">sym2</span></code> 411 to <code class="computeroutput"><span class="identifier">sym</span></code>. 412 </p> 413 </td> 414</tr> 415<tr> 416<td> 417 <p> 418 <code class="computeroutput"><span class="identifier">sym</span> <span class="special">=</span> 419 <span class="identifier">s1</span><span class="special">,</span> 420 <span class="identifier">s2</span><span class="special">,</span> 421 <span class="special">...,</span> <span class="identifier">sN</span></code> 422 </p> 423 </td> 424<td> 425 <p> 426 Assign one or more symbols (<code class="computeroutput"><span class="identifier">s1</span></code>...<code class="computeroutput"><span class="identifier">sN</span></code>) to <code class="computeroutput"><span class="identifier">sym</span></code>. 427 The associated data values of type <code class="computeroutput"><span class="identifier">T</span></code> 428 are default constructed. 429 </p> 430 </td> 431</tr> 432<tr> 433<td> 434 <p> 435 <code class="computeroutput"><span class="identifier">sym</span> <span class="special">+=</span> 436 <span class="identifier">s1</span><span class="special">,</span> 437 <span class="identifier">s2</span><span class="special">,</span> 438 <span class="special">...,</span> <span class="identifier">sN</span></code> 439 </p> 440 </td> 441<td> 442 <p> 443 Add one or more symbols (<code class="computeroutput"><span class="identifier">s1</span></code>...<code class="computeroutput"><span class="identifier">sN</span></code>) to <code class="computeroutput"><span class="identifier">sym</span></code>. 444 The associated data values of type <code class="computeroutput"><span class="identifier">T</span></code> 445 are default constructed. 446 </p> 447 </td> 448</tr> 449<tr> 450<td> 451 <p> 452 <code class="computeroutput"><span class="identifier">sym</span><span class="special">.</span><span class="identifier">add</span><span class="special">(</span><span class="identifier">s1</span><span class="special">)(</span><span class="identifier">s2</span><span class="special">)...(</span><span class="identifier">sN</span><span class="special">)</span></code> 453 </p> 454 </td> 455<td> 456 <p> 457 Add one or more symbols (<code class="computeroutput"><span class="identifier">s1</span></code>...<code class="computeroutput"><span class="identifier">sN</span></code>) to <code class="computeroutput"><span class="identifier">sym</span></code>. 458 The associated data values of type <code class="computeroutput"><span class="identifier">T</span></code> 459 are default constructed. 460 </p> 461 </td> 462</tr> 463<tr> 464<td> 465 <p> 466 <code class="computeroutput"><span class="identifier">sym</span><span class="special">.</span><span class="identifier">add</span><span class="special">(</span><span class="identifier">s1</span><span class="special">,</span> 467 <span class="identifier">d1</span><span class="special">)(</span><span class="identifier">s2</span><span class="special">,</span> 468 <span class="identifier">d2</span><span class="special">)...(</span><span class="identifier">sN</span><span class="special">,</span> 469 <span class="identifier">dN</span><span class="special">)</span></code> 470 </p> 471 </td> 472<td> 473 <p> 474 Add one or more symbols (<code class="computeroutput"><span class="identifier">s1</span></code>...<code class="computeroutput"><span class="identifier">sN</span></code>) with associated data 475 (<code class="computeroutput"><span class="identifier">d1</span></code>...<code class="computeroutput"><span class="identifier">dN</span></code>) to <code class="computeroutput"><span class="identifier">sym</span></code>. 476 </p> 477 </td> 478</tr> 479<tr> 480<td> 481 <p> 482 <code class="computeroutput"><span class="identifier">sym</span> <span class="special">-=</span> 483 <span class="identifier">s1</span><span class="special">,</span> 484 <span class="identifier">s2</span><span class="special">,</span> 485 <span class="special">...,</span> <span class="identifier">sN</span></code> 486 </p> 487 </td> 488<td> 489 <p> 490 Remove one or more symbols (<code class="computeroutput"><span class="identifier">s1</span></code>...<code class="computeroutput"><span class="identifier">sN</span></code>) from <code class="computeroutput"><span class="identifier">sym</span></code>. 491 </p> 492 </td> 493</tr> 494<tr> 495<td> 496 <p> 497 <code class="computeroutput"><span class="identifier">sym</span><span class="special">.</span><span class="identifier">remove</span><span class="special">(</span><span class="identifier">s1</span><span class="special">)(</span><span class="identifier">s2</span><span class="special">)...(</span><span class="identifier">sN</span><span class="special">)</span></code> 498 </p> 499 </td> 500<td> 501 <p> 502 Remove one or more symbols (<code class="computeroutput"><span class="identifier">s1</span></code>...<code class="computeroutput"><span class="identifier">sN</span></code>) from <code class="computeroutput"><span class="identifier">sym</span></code>. 503 </p> 504 </td> 505</tr> 506<tr> 507<td> 508 <p> 509 <code class="computeroutput"><span class="identifier">sym</span><span class="special">.</span><span class="identifier">clear</span><span class="special">()</span></code> 510 </p> 511 </td> 512<td> 513 <p> 514 Erase all of the symbols in <code class="computeroutput"><span class="identifier">sym</span></code>. 515 </p> 516 </td> 517</tr> 518<tr> 519<td> 520 <p> 521 <code class="computeroutput"><span class="identifier">sym</span><span class="special">.</span><span class="identifier">at</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code> 522 </p> 523 </td> 524<td> 525 <p> 526 Return a reference to the object associated with symbol, <code class="computeroutput"><span class="identifier">s</span></code>. If <code class="computeroutput"><span class="identifier">sym</span></code> 527 does not already contain such an object, <code class="computeroutput"><span class="identifier">at</span></code> 528 inserts the default object <code class="computeroutput"><span class="identifier">T</span><span class="special">()</span></code>. 529 </p> 530 </td> 531</tr> 532<tr> 533<td> 534 <p> 535 <code class="computeroutput"><span class="identifier">sym</span><span class="special">.</span><span class="identifier">find</span><span class="special">(</span><span class="identifier">s</span><span class="special">)</span></code> 536 </p> 537 </td> 538<td> 539 <p> 540 Return a pointer to the object associated with symbol, <code class="computeroutput"><span class="identifier">s</span></code>. If <code class="computeroutput"><span class="identifier">sym</span></code> 541 does not already contain such an object, <code class="computeroutput"><span class="identifier">find</span></code> 542 returns a null pointer. 543 </p> 544 </td> 545</tr> 546<tr> 547<td> 548 <p> 549 <code class="computeroutput"><span class="identifier">sym</span><span class="special">.</span><span class="identifier">for_each</span><span class="special">(</span><span class="identifier">f</span><span class="special">)</span></code> 550 </p> 551 </td> 552<td> 553 <p> 554 For each symbol in <code class="computeroutput"><span class="identifier">sym</span></code> 555 <code class="computeroutput"><span class="identifier">s</span></code> invoke <code class="computeroutput"><span class="identifier">f</span><span class="special">(</span><span class="keyword">typename</span> <span class="identifier">Lookup</span><span class="special">::</span><span class="identifier">value_type</span><span class="special">)</span></code>. 556 </p> 557 </td> 558</tr> 559<tr> 560<td> 561 <p> 562 <code class="computeroutput"><span class="identifier">sym</span><span class="special">.</span><span class="identifier">name</span><span class="special">()</span></code> 563 </p> 564 </td> 565<td> 566 <p> 567 Retrieve the current name of the symbols object. 568 </p> 569 </td> 570</tr> 571<tr> 572<td> 573 <p> 574 <code class="computeroutput"><span class="identifier">sym</span><span class="special">.</span><span class="identifier">name</span><span class="special">(</span><span class="identifier">name</span><span class="special">)</span></code> 575 </p> 576 </td> 577<td> 578 <p> 579 Set the current name of the symbols object to be <code class="computeroutput"><span class="identifier">name</span></code>. 580 </p> 581 </td> 582</tr> 583</tbody> 584</table></div> 585<p> 586 The symbols generator uses the supplied attribute as the key to be looked 587 up in the internal associative container. If the key exists the generator 588 emits the associated value and succeeds (unless the underlying output 589 stream reports an error). If the value type stored in the symbol generator 590 is <code class="computeroutput"><span class="identifier">unused_type</span></code> it will 591 emit the key instead. If the key does not exist the generator fails while 592 not emitting anything. 593 </p> 594<h6> 595<a name="spirit.karma.reference.string.symbols.h7"></a> 596 <span class="phrase"><a name="spirit.karma.reference.string.symbols.attributes"></a></span><a class="link" href="symbols.html#spirit.karma.reference.string.symbols.attributes">Attributes</a> 597 </h6> 598<p> 599 The attribute of <code class="computeroutput"><span class="identifier">symbol</span><span class="special"><</span><span class="identifier">Attrib</span><span class="special">,</span> <span class="identifier">T</span><span class="special">></span></code> is <code class="computeroutput"><span class="identifier">Attrib</span></code>. 600 </p> 601<p> 602 If the supplied attribute is a <a href="../../../../../../../../libs/fusion/doc/html/index.html" target="_top">Boost.Fusion</a> 603 sequence, then the symbol table generator will use the first element 604 of that <a href="../../../../../../../../libs/fusion/doc/html/index.html" target="_top">Boost.Fusion</a> 605 sequence as the key to be used for lookup. The type of that first element 606 needs to be convertible to <code class="computeroutput"><span class="identifier">Attrib</span></code>. 607 In this case the second element of the <a href="../../../../../../../../libs/fusion/doc/html/index.html" target="_top">Boost.Fusion</a> 608 sequence is used as the attribute while calling a generator derived from 609 the value stored in the symbol table for the found entry. 610 </p> 611<p> 612 If the supplied attribute is a container type (<a class="link" href="../../../advanced/customize/is_container.html" title="Determine if a Type Should be Treated as a Container (Qi and Karma)"><code class="computeroutput"><span class="identifier">traits</span><span class="special">::</span><span class="identifier">is_container</span></code></a> resolves to <code class="computeroutput"><span class="identifier">mpl</span><span class="special">::</span><span class="identifier">true_</span></code>), then the symbol table generator 613 will use the first element stored in that container as the key to be 614 used for lookup. The <code class="computeroutput"><span class="identifier">value_type</span></code> 615 (returned by <a class="link" href="../../../advanced/customize/store_value/container_value.html" title="Determine the Type to be Stored in a Container (Qi)"><code class="computeroutput"><span class="identifier">traits</span><span class="special">::</span><span class="identifier">container_value</span></code></a>) has to be convertible 616 to <code class="computeroutput"><span class="identifier">Attrib</span></code>. In this case 617 the second element stored in that container is used as the attribute 618 while calling a generator derived from the value stored in the symbol 619 table for the found entry. 620 </p> 621<p> 622 If the supplied attribute is not a <a href="../../../../../../../../libs/fusion/doc/html/index.html" target="_top">Boost.Fusion</a> 623 sequence and not a container type, the supplied attribute is directly 624 used as the key for item lookup. The attribute is used as the attribute 625 while calling a generator derived from the value stored in the symbol 626 table for the found entry. 627 </p> 628<p> 629 In any case, because the supplied key (i.e. either the first element 630 of the <a href="../../../../../../../../libs/fusion/doc/html/index.html" target="_top">Boost.Fusion</a> 631 sequence, the first container element, or the attribute otherwise) is 632 passed as the attribute to a generator derived from the value stored 633 in the symbol table for the found entry, the symbol table may store generators, 634 which will produce output based on that value. For instance: 635 </p> 636<pre class="programlisting"><span class="comment">// The symbol table maps a single character key to a rule<></span> 637<span class="comment">// The rule<> exposes an attribute of char as well</span> 638<span class="identifier">rule</span><span class="special"><</span><span class="identifier">output_iterator_type</span><span class="special">,</span> <span class="keyword">char</span><span class="special">()></span> <span class="identifier">r1</span> <span class="special">=</span> <span class="identifier">char_</span><span class="special">;</span> 639 640<span class="identifier">symbols</span><span class="special"><</span><span class="keyword">char</span><span class="special">,</span> <span class="identifier">rule</span><span class="special"><</span><span class="identifier">output_iterator_type</span><span class="special">,</span> <span class="keyword">char</span><span class="special">()></span> <span class="special">></span> <span class="identifier">sym</span><span class="special">;</span> 641<span class="identifier">sym</span><span class="special">.</span><span class="identifier">add</span> 642 <span class="special">(</span><span class="char">'j'</span><span class="special">,</span> <span class="identifier">r1</span><span class="special">.</span><span class="identifier">alias</span><span class="special">())</span> 643 <span class="special">(</span><span class="char">'h'</span><span class="special">,</span> <span class="identifier">r1</span><span class="special">.</span><span class="identifier">alias</span><span class="special">())</span> 644 <span class="special">(</span><span class="char">'t'</span><span class="special">,</span> <span class="identifier">r1</span><span class="special">.</span><span class="identifier">alias</span><span class="special">())</span> 645 <span class="special">(</span><span class="char">'k'</span><span class="special">,</span> <span class="identifier">r1</span><span class="special">.</span><span class="identifier">alias</span><span class="special">())</span> 646<span class="special">;</span> 647 648<span class="comment">// Supplying a fusion vector as the attribute will use the first element</span> 649<span class="comment">// (the 'j') as the key to be looked up, while the second element (the 'J') </span> 650<span class="comment">// is passed on as the attribute to the rule<> stored in the symbol table. </span> 651<span class="comment">// Consequently, the example generates a single 'J'.</span> 652<span class="identifier">BOOST_ASSERT</span><span class="special">(</span><span class="identifier">test</span><span class="special">(</span><span class="string">"J"</span><span class="special">,</span> <span class="identifier">sym</span><span class="special">,</span> <span class="identifier">make_vector</span><span class="special">(</span><span class="char">'j'</span><span class="special">,</span> <span class="char">'J'</span><span class="special">)));</span> 653</pre> 654<h6> 655<a name="spirit.karma.reference.string.symbols.h8"></a> 656 <span class="phrase"><a name="spirit.karma.reference.string.symbols.complexity"></a></span><a class="link" href="symbols.html#spirit.karma.reference.string.symbols.complexity">Complexity</a> 657 </h6> 658<p> 659 The default implementation uses a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">map</span><span class="special"><></span></code> or a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">set</span><span class="special"><></span></code> with a complexity of: 660 </p> 661<div class="blockquote"><blockquote class="blockquote"><p> 662 O(log n) 663 </p></blockquote></div> 664<p> 665 Where n is the number of stored symbols. 666 </p> 667<h6> 668<a name="spirit.karma.reference.string.symbols.h9"></a> 669 <span class="phrase"><a name="spirit.karma.reference.string.symbols.example"></a></span><a class="link" href="symbols.html#spirit.karma.reference.string.symbols.example">Example</a> 670 </h6> 671<div class="note"><table border="0" summary="Note"> 672<tr> 673<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../images/note.png"></td> 674<th align="left">Note</th> 675</tr> 676<tr><td align="left" valign="top"><p> 677 The test harness for the example(s) below is presented in the <a class="link" href="../basics.html#spirit.karma.reference.basics.examples">Basics Examples</a> 678 section. 679 </p></td></tr> 680</table></div> 681<p> 682 Some includes: 683 </p> 684<p> 685</p> 686<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">spirit</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">karma</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 687<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">spirit</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">support_utree</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 688<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">spirit</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">phoenix_core</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 689<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">spirit</span><span class="special">/</span><span class="identifier">include</span><span class="special">/</span><span class="identifier">phoenix_operator</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 690<span class="preprocessor">#include</span> <span class="special"><</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">std_pair</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 691<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span> 692<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">string</span><span class="special">></span> 693</pre> 694<p> 695 </p> 696<p> 697 Some using declarations: 698 </p> 699<p> 700</p> 701<pre class="programlisting"><span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">spirit</span><span class="special">::</span><span class="identifier">karma</span><span class="special">::</span><span class="identifier">symbols</span><span class="special">;</span> 702</pre> 703<p> 704 </p> 705<p> 706 Basic usage of <code class="computeroutput"><span class="identifier">symbol</span></code> 707 generators: 708 </p> 709<p> 710</p> 711<pre class="programlisting"><span class="identifier">symbols</span><span class="special"><</span><span class="keyword">char</span><span class="special">,</span> <span class="keyword">char</span> <span class="keyword">const</span><span class="special">*></span> <span class="identifier">sym</span><span class="special">;</span> 712 713<span class="identifier">sym</span><span class="special">.</span><span class="identifier">add</span> 714 <span class="special">(</span><span class="char">'a'</span><span class="special">,</span> <span class="string">"Apple"</span><span class="special">)</span> 715 <span class="special">(</span><span class="char">'b'</span><span class="special">,</span> <span class="string">"Banana"</span><span class="special">)</span> 716 <span class="special">(</span><span class="char">'o'</span><span class="special">,</span> <span class="string">"Orange"</span><span class="special">)</span> 717<span class="special">;</span> 718 719<span class="identifier">test_generator_attr</span><span class="special">(</span><span class="string">"Banana"</span><span class="special">,</span> <span class="identifier">sym</span><span class="special">,</span> <span class="char">'b'</span><span class="special">);</span> 720</pre> 721<p> 722 </p> 723</div> 724<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 725<td align="left"></td> 726<td align="right"><div class="copyright-footer">Copyright © 2001-2011 Joel de Guzman, Hartmut Kaiser<p> 727 Distributed under the Boost Software License, Version 1.0. (See accompanying 728 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>) 729 </p> 730</div></td> 731</tr></table> 732<hr> 733<div class="spirit-nav"> 734<a accesskey="p" href="string.html"><img src="../../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../string.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="../../performance_measurements.html"><img src="../../../../../../../../doc/src/images/next.png" alt="Next"></a> 735</div> 736</body> 737</html> 738
