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  26 <div class="titlepage"><div><div><h4 class="title">
  27 <a name="boost_regex.ref.concepts.traits_concept"></a><a class="link" href="traits_concept.html" title="Traits Class Requirements">Traits Class
  28         Requirements</a>
  29 </h4></div></div></div>
  30 <p>
  31           There are two sets of requirements for the <code class="computeroutput"><span class="identifier">traits</span></code>
  32           template argument to <a class="link" href="../basic_regex.html" title="basic_regex"><code class="computeroutput"><span class="identifier">basic_regex</span></code></a>: a minimal interface
  33           (which is part of the regex standardization proposal), and an optional
  34           Boost-specific enhanced interface.
  35         </p>
  36 <h5>
  37 <a name="boost_regex.ref.concepts.traits_concept.h0"></a>
  38           <span class="phrase"><a name="boost_regex.ref.concepts.traits_concept.minimal_requirements"></a></span><a class="link" href="traits_concept.html#boost_regex.ref.concepts.traits_concept.minimal_requirements">Minimal
  39           requirements.</a>
  40         </h5>
  41 <p>
  42           In the following table <code class="computeroutput"><span class="identifier">X</span></code>
  43           denotes a traits class defining types and functions for the character container
  44           type <code class="computeroutput"><span class="identifier">charT</span></code>; <span class="emphasis"><em>u</em></span>
  45           is an object of type <code class="computeroutput"><span class="identifier">X</span></code>;
  46           <span class="emphasis"><em>v</em></span> is an object of type <code class="computeroutput"><span class="keyword">const</span>
  47           <span class="identifier">X</span></code>; <span class="emphasis"><em>p</em></span> is
  48           a value of type <code class="computeroutput"><span class="keyword">const</span> <span class="identifier">charT</span><span class="special">*</span></code>; <span class="emphasis"><em>I1</em></span> and <span class="emphasis"><em>I2</em></span>
  49           are Input Iterators; <span class="emphasis"><em>c</em></span> is a value of type <code class="computeroutput"><span class="keyword">const</span> <span class="identifier">charT</span></code>;
  50           <span class="emphasis"><em>s</em></span> is an object of type <code class="computeroutput"><span class="identifier">X</span><span class="special">::</span><span class="identifier">string_type</span></code>;
  51           <span class="emphasis"><em>cs</em></span> is an object of type <code class="computeroutput"><span class="keyword">const</span>
  52           <span class="identifier">X</span><span class="special">::</span><span class="identifier">string_type</span></code>; <span class="emphasis"><em>b</em></span> is
  53           a value of type <code class="computeroutput"><span class="keyword">bool</span></code>; <span class="emphasis"><em>I</em></span>
  54           is a value of type <code class="computeroutput"><span class="keyword">int</span></code>; <span class="emphasis"><em>F1</em></span>
  55           and <span class="emphasis"><em>F2</em></span> are values of type <code class="computeroutput"><span class="keyword">const</span>
  56           <span class="identifier">charT</span><span class="special">*</span></code>;
  57           and <span class="emphasis"><em>loc</em></span> is an object of type <code class="computeroutput"><span class="identifier">X</span><span class="special">::</span><span class="identifier">locale_type</span></code>.
  58         </p>
  59 <div class="informaltable"><table class="table">
  60 <colgroup>
  61 <col>
  62 <col>
  63 <col>
  64 </colgroup>
  65 <thead><tr>
  66 <th>
  67                   <p>
  68                     Expression
  69                   </p>
  70                 </th>
  71 <th>
  72                   <p>
  73                     Return type
  74                   </p>
  75                 </th>
  76 <th>
  77                   <p>
  78                     Assertion / Note Pre / Post condition
  79                   </p>
  80                 </th>
  81 </tr></thead>
  82 <tbody>
  83 <tr>
  84 <td>
  85                   <p>
  86                     X::char_type
  87                   </p>
  88                 </td>
  89 <td>
  90                   <p>
  91                     charT
  92                   </p>
  93                 </td>
  94 <td>
  95                   <p>
  96                     The character container type used in the implementation of class
  97                     template basic_regex.
  98                   </p>
  99                 </td>
 100 </tr>
 101 <tr>
 102 <td>
 103                   <p>
 104                     X::size_type
 105                   </p>
 106                 </td>
 107 <td>
 108                 </td>
 109 <td>
 110                   <p>
 111                     An unsigned integer type, capable of holding the length of a
 112                     null-terminated string of charT's.
 113                   </p>
 114                 </td>
 115 </tr>
 116 <tr>
 117 <td>
 118                   <p>
 119                     X::string_type
 120                   </p>
 121                 </td>
 122 <td>
 123                   <p>
 124                     std::basic_string&lt;charT&gt; or std::vector&lt;charT&gt;
 125                   </p>
 126                 </td>
 127 <td>
 128                 </td>
 129 </tr>
 130 <tr>
 131 <td>
 132                   <p>
 133                     X::locale_type
 134                   </p>
 135                 </td>
 136 <td>
 137                   <p>
 138                     Implementation defined
 139                   </p>
 140                 </td>
 141 <td>
 142                   <p>
 143                     A copy constructible type that represents the locale used by
 144                     the traits class.
 145                   </p>
 146                 </td>
 147 </tr>
 148 <tr>
 149 <td>
 150                   <p>
 151                     X::char_class_type
 152                   </p>
 153                 </td>
 154 <td>
 155                   <p>
 156                     Implementation defined
 157                   </p>
 158                 </td>
 159 <td>
 160                   <p>
 161                     A bitmask type representing a particular character classification.
 162                     Multiple values of this type can be bitwise-or'ed together to
 163                     obtain a new valid value.
 164                   </p>
 165                 </td>
 166 </tr>
 167 <tr>
 168 <td>
 169                   <p>
 170                     X::length(p)
 171                   </p>
 172                 </td>
 173 <td>
 174                   <p>
 175                     X::size_type
 176                   </p>
 177                 </td>
 178 <td>
 179                   <p>
 180                     Yields the smallest i such that p[i] == 0. Complexity is linear
 181                     in i.
 182                   </p>
 183                 </td>
 184 </tr>
 185 <tr>
 186 <td>
 187                   <p>
 188                     v.translate(c)
 189                   </p>
 190                 </td>
 191 <td>
 192                   <p>
 193                     X::char_type
 194                   </p>
 195                 </td>
 196 <td>
 197                   <p>
 198                     Returns a character such that for any character d that is to
 199                     be considered equivalent to c then v.translate(c) == v.translate(d).
 200                   </p>
 201                 </td>
 202 </tr>
 203 <tr>
 204 <td>
 205                   <p>
 206                     v.translate_nocase(c)
 207                   </p>
 208                 </td>
 209 <td>
 210                   <p>
 211                     X::char_type
 212                   </p>
 213                 </td>
 214 <td>
 215                   <p>
 216                     For all characters C that are to be considered equivalent to
 217                     c when comparisons are to be performed without regard to case,
 218                     then v.translate_nocase(c) == v.translate_nocase(C).
 219                   </p>
 220                 </td>
 221 </tr>
 222 <tr>
 223 <td>
 224                   <p>
 225                     v.transform(F1, F2)
 226                   </p>
 227                 </td>
 228 <td>
 229                   <p>
 230                     X::string_type
 231                   </p>
 232                 </td>
 233 <td>
 234                   <p>
 235                     Returns a sort key for the character sequence designated by the
 236                     iterator range [F1, F2) such that if the character sequence [G1,
 237                     G2) sorts before the character sequence [H1, H2) then v.transform(G1,
 238                     G2) &lt; v.transform(H1, H2).
 239                   </p>
 240                 </td>
 241 </tr>
 242 <tr>
 243 <td>
 244                   <p>
 245                     v.transform_primary(F1, F2)
 246                   </p>
 247                 </td>
 248 <td>
 249                   <p>
 250                     X::string_type
 251                   </p>
 252                 </td>
 253 <td>
 254                   <p>
 255                     Returns a sort key for the character sequence designated by the
 256                     iterator range [F1, F2) such that if the character sequence [G1,
 257                     G2) sorts before the character sequence [H1, H2) when character
 258                     case is not considered then v.transform_primary(G1, G2) &lt;
 259                     v.transform_primary(H1, H2).
 260                   </p>
 261                 </td>
 262 </tr>
 263 <tr>
 264 <td>
 265                   <p>
 266                     v.lookup_classname(F1, F2)
 267                   </p>
 268                 </td>
 269 <td>
 270                   <p>
 271                     X::char_class_type
 272                   </p>
 273                 </td>
 274 <td>
 275                   <p>
 276                     Converts the character sequence designated by the iterator range
 277                     [F1,F2) into a bitmask type that can subsequently be passed to
 278                     isctype. Values returned from lookup_classname can be safely
 279                     bitwise or'ed together. Returns 0 if the character sequence is
 280                     not the name of a character class recognized by X. The value
 281                     returned shall be independent of the case of the characters in
 282                     the sequence.
 283                   </p>
 284                 </td>
 285 </tr>
 286 <tr>
 287 <td>
 288                   <p>
 289                     v.lookup_collatename(F1, F2)
 290                   </p>
 291                 </td>
 292 <td>
 293                   <p>
 294                     X::string_type
 295                   </p>
 296                 </td>
 297 <td>
 298                   <p>
 299                     Returns a sequence of characters that represents the collating
 300                     element consisting of the character sequence designated by the
 301                     iterator range [F1, F2). Returns an empty string if the character
 302                     sequence is not a valid collating element.
 303                   </p>
 304                 </td>
 305 </tr>
 306 <tr>
 307 <td>
 308                   <p>
 309                     v.isctype(c, v.lookup_classname (F1, F2))
 310                   </p>
 311                 </td>
 312 <td>
 313                   <p>
 314                     bool
 315                   </p>
 316                 </td>
 317 <td>
 318                   <p>
 319                     Returns true if character c is a member of the character class
 320                     designated by the iterator range [F1, F2), false otherwise.
 321                   </p>
 322                 </td>
 323 </tr>
 324 <tr>
 325 <td>
 326                   <p>
 327                     v.value(c, I)
 328                   </p>
 329                 </td>
 330 <td>
 331                   <p>
 332                     int
 333                   </p>
 334                 </td>
 335 <td>
 336                   <p>
 337                     Returns the value represented by the digit c in base I if the
 338                     character c is a valid digit in base I; otherwise returns -1.
 339                     [Note: the value of I will only be 8, 10, or 16. -end note]
 340                   </p>
 341                 </td>
 342 </tr>
 343 <tr>
 344 <td>
 345                   <p>
 346                     u.imbue(loc)
 347                   </p>
 348                 </td>
 349 <td>
 350                   <p>
 351                     X::locale_type
 352                   </p>
 353                 </td>
 354 <td>
 355                   <p>
 356                     Imbues u with the locale loc, returns the previous locale used
 357                     by u if any.
 358                   </p>
 359                 </td>
 360 </tr>
 361 <tr>
 362 <td>
 363                   <p>
 364                     v.getloc()
 365                   </p>
 366                 </td>
 367 <td>
 368                   <p>
 369                     X::locale_type
 370                   </p>
 371                 </td>
 372 <td>
 373                   <p>
 374                     Returns the current locale used by v if any.
 375                   </p>
 376                 </td>
 377 </tr>
 378 </tbody>
 379 </table></div>
 380 <h5>
 381 <a name="boost_regex.ref.concepts.traits_concept.h1"></a>
 382           <span class="phrase"><a name="boost_regex.ref.concepts.traits_concept.additional_optional_requirements"></a></span><a class="link" href="traits_concept.html#boost_regex.ref.concepts.traits_concept.additional_optional_requirements">Additional
 383           Optional Requirements</a>
 384         </h5>
 385 <p>
 386           The following additional requirements are strictly optional, however in
 387           order for <a class="link" href="../basic_regex.html" title="basic_regex"><code class="computeroutput"><span class="identifier">basic_regex</span></code></a>
 388           to take advantage of these additional interfaces, all of the following
 389           requirements must be met; <a class="link" href="../basic_regex.html" title="basic_regex"><code class="computeroutput"><span class="identifier">basic_regex</span></code></a> will detect the presence
 390           or absence of the member <code class="computeroutput"><span class="identifier">boost_extensions_tag</span></code>
 391           and configure itself appropriately.
 392         </p>
 393 <div class="informaltable"><table class="table">
 394 <colgroup>
 395 <col>
 396 <col>
 397 <col>
 398 </colgroup>
 399 <thead><tr>
 400 <th>
 401                   <p>
 402                     Expression
 403                   </p>
 404                 </th>
 405 <th>
 406                   <p>
 407                     Result
 408                   </p>
 409                 </th>
 410 <th>
 411                   <p>
 412                     Assertion / Note Pre / Post condition
 413                   </p>
 414                 </th>
 415 </tr></thead>
 416 <tbody>
 417 <tr>
 418 <td>
 419                   <p>
 420                     X::boost_extensions_tag
 421                   </p>
 422                 </td>
 423 <td>
 424                   <p>
 425                     An unspecified type.
 426                   </p>
 427                 </td>
 428 <td>
 429                   <p>
 430                     When present, all of the extensions listed in this table must
 431                     be present.
 432                   </p>
 433                 </td>
 434 </tr>
 435 <tr>
 436 <td>
 437                   <p>
 438                     v.syntax_type(c)
 439                   </p>
 440                 </td>
 441 <td>
 442                   <p>
 443                     regex_constants::syntax_type
 444                   </p>
 445                 </td>
 446 <td>
 447                   <p>
 448                     Returns a symbolic value of type regex_constants::syntax_type
 449                     that signifies the meaning of character c within the regular
 450                     expression grammar.
 451                   </p>
 452                 </td>
 453 </tr>
 454 <tr>
 455 <td>
 456                   <p>
 457                     v.escape_syntax_type(c)
 458                   </p>
 459                 </td>
 460 <td>
 461                   <p>
 462                     regex_constants::escape_syntax_type
 463                   </p>
 464                 </td>
 465 <td>
 466                   <p>
 467                     Returns a symbolic value of type regex_constants::escape_syntax_type,
 468                     that signifies the meaning of character c within the regular
 469                     expression grammar, when c has been preceded by an escape character.
 470                     Precondition: if b is the character preceding c in the expression
 471                     being parsed then: <code class="computeroutput"><span class="identifier">v</span><span class="special">.</span><span class="identifier">syntax_type</span><span class="special">(</span><span class="identifier">b</span><span class="special">)</span> <span class="special">==</span>
 472                     <span class="identifier">syntax_escape</span></code>
 473                   </p>
 474                 </td>
 475 </tr>
 476 <tr>
 477 <td>
 478                   <p>
 479                     v.translate(c, b)
 480                   </p>
 481                 </td>
 482 <td>
 483                   <p>
 484                     X::char_type
 485                   </p>
 486                 </td>
 487 <td>
 488                   <p>
 489                     Returns a character d such that: for any character d that is
 490                     to be considered equivalent to c then <code class="computeroutput"><span class="identifier">v</span><span class="special">.</span><span class="identifier">translate</span><span class="special">(</span><span class="identifier">c</span><span class="special">,</span><span class="keyword">false</span><span class="special">)==</span><span class="identifier">v</span><span class="special">.</span><span class="identifier">translate</span><span class="special">(</span><span class="identifier">d</span><span class="special">,</span><span class="keyword">false</span><span class="special">)</span></code>. Likewise for all characters
 491                     C that are to be considered equivalent to c when comparisons
 492                     are to be performed without regard to case, then <code class="computeroutput"><span class="identifier">v</span><span class="special">.</span><span class="identifier">translate</span><span class="special">(</span><span class="identifier">c</span><span class="special">,</span><span class="keyword">true</span><span class="special">)==</span><span class="identifier">v</span><span class="special">.</span><span class="identifier">translate</span><span class="special">(</span><span class="identifier">C</span><span class="special">,</span><span class="keyword">true</span><span class="special">)</span></code>.
 493                   </p>
 494                 </td>
 495 </tr>
 496 <tr>
 497 <td>
 498                   <p>
 499                     v.toi(I1, I2, i)
 500                   </p>
 501                 </td>
 502 <td>
 503                   <p>
 504                     An integer type capable of holding either a charT or an int.
 505                   </p>
 506                 </td>
 507 <td>
 508                   <p>
 509                     Behaves as follows: if <code class="computeroutput"><span class="identifier">p</span>
 510                     <span class="special">==</span> <span class="identifier">q</span></code>
 511                     or if <code class="computeroutput"><span class="special">*</span><span class="identifier">p</span></code>
 512                     is not a digit character then returns -1. Otherwise performs
 513                     formatted numeric input on the sequence [p,q) and returns the
 514                     result as an int. Postcondition: either p == q or *p is a non-digit
 515                     character.
 516                   </p>
 517                 </td>
 518 </tr>
 519 <tr>
 520 <td>
 521                   <p>
 522                     v.error_string(I)
 523                   </p>
 524                 </td>
 525 <td>
 526                   <p>
 527                     std::string
 528                   </p>
 529                 </td>
 530 <td>
 531                   <p>
 532                     Returns a human readable error string for the error condition
 533                     i, where i is one of the values enumerated by type regex_constants::error_type.
 534                     If the value <span class="emphasis"><em>I</em></span> is not recognized then returns
 535                     the string "Unknown error" or a localized equivalent.
 536                   </p>
 537                 </td>
 538 </tr>
 539 <tr>
 540 <td>
 541                   <p>
 542                     v.tolower(c)
 543                   </p>
 544                 </td>
 545 <td>
 546                   <p>
 547                     X::char_type
 548                   </p>
 549                 </td>
 550 <td>
 551                   <p>
 552                     Converts c to lower case, used for Perl-style \l and \L formatting
 553                     operations.
 554                   </p>
 555                 </td>
 556 </tr>
 557 <tr>
 558 <td>
 559                   <p>
 560                     v.toupper(c)
 561                   </p>
 562                 </td>
 563 <td>
 564                   <p>
 565                     X::char_type
 566                   </p>
 567                 </td>
 568 <td>
 569                   <p>
 570                     Converts c to upper case, used for Perl-style \u and \U formatting
 571                     operations.
 572                   </p>
 573                 </td>
 574 </tr>
 575 </tbody>
 576 </table></div>
 577 </div>
 578 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 579 <td align="left"></td>
 580 <td align="right"><div class="copyright-footer">Copyright &#169; 1998-2013 John Maddock<p>
 581         Distributed under the Boost Software License, Version 1.0. (See accompanying
 582         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>)
 583       </p>
 584 </div></td>
 585 </tr></table>
 586 <hr>
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