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24 | </div> | |
25 | <div class="section"> | |
26 | <div class="titlepage"><div><div><h3 class="title"> | |
27 | <a name="boost_regex.format.boost_format_syntax"></a><a class="link" href="boost_format_syntax.html" title="Boost-Extended Format String Syntax">Boost-Extended | |
28 | Format String Syntax</a> | |
29 | </h3></div></div></div> | |
30 | <p> | |
31 | Boost-Extended format strings treat all characters as literals except for | |
32 | '$', '\', '(', ')', '?', and ':'. | |
33 | </p> | |
34 | <h5> | |
35 | <a name="boost_regex.format.boost_format_syntax.h0"></a> | |
36 | <span class="phrase"><a name="boost_regex.format.boost_format_syntax.grouping"></a></span><a class="link" href="boost_format_syntax.html#boost_regex.format.boost_format_syntax.grouping">Grouping</a> | |
37 | </h5> | |
38 | <p> | |
39 | The characters '(' and ')' perform lexical grouping, so use \( and \) if | |
40 | you want a to output literal parenthesis. | |
41 | </p> | |
42 | <h5> | |
43 | <a name="boost_regex.format.boost_format_syntax.h1"></a> | |
44 | <span class="phrase"><a name="boost_regex.format.boost_format_syntax.conditionals"></a></span><a class="link" href="boost_format_syntax.html#boost_regex.format.boost_format_syntax.conditionals">Conditionals</a> | |
45 | </h5> | |
46 | <p> | |
47 | The character '?' begins a conditional expression, the general form is: | |
48 | </p> | |
49 | <p> | |
50 | ?Ntrue-expression:false-expression | |
51 | </p> | |
52 | <p> | |
53 | where N is decimal digit. | |
54 | </p> | |
55 | <p> | |
56 | If sub-expression N was matched, then true-expression is evaluated and sent | |
57 | to output, otherwise false-expression is evaluated and sent to output. | |
58 | </p> | |
59 | <p> | |
60 | You will normally need to surround a conditional-expression with parenthesis | |
61 | in order to prevent ambiguities. | |
62 | </p> | |
63 | <p> | |
64 | For example, the format string "(?1foo:bar)" will replace each | |
65 | match found with "foo" if the sub-expression $1 was matched, and | |
66 | with "bar" otherwise. | |
67 | </p> | |
68 | <p> | |
69 | For sub-expressions with an index greater than 9, or for access to named | |
70 | sub-expressions use: | |
71 | </p> | |
72 | <p> | |
73 | ?{INDEX}true-expression:false-expression | |
74 | </p> | |
75 | <p> | |
76 | or | |
77 | </p> | |
78 | <p> | |
79 | ?{NAME}true-expression:false-expression | |
80 | </p> | |
81 | <h5> | |
82 | <a name="boost_regex.format.boost_format_syntax.h2"></a> | |
83 | <span class="phrase"><a name="boost_regex.format.boost_format_syntax.placeholder_sequences"></a></span><a class="link" href="boost_format_syntax.html#boost_regex.format.boost_format_syntax.placeholder_sequences">Placeholder | |
84 | Sequences</a> | |
85 | </h5> | |
86 | <p> | |
87 | Placeholder sequences specify that some part of what matched the regular | |
88 | expression should be sent to output as follows: | |
89 | </p> | |
90 | <div class="informaltable"><table class="table"> | |
91 | <colgroup> | |
92 | <col> | |
93 | <col> | |
94 | </colgroup> | |
95 | <thead><tr> | |
96 | <th> | |
97 | <p> | |
98 | Placeholder | |
99 | </p> | |
100 | </th> | |
101 | <th> | |
102 | <p> | |
103 | Meaning | |
104 | </p> | |
105 | </th> | |
106 | </tr></thead> | |
107 | <tbody> | |
108 | <tr> | |
109 | <td> | |
110 | <p> | |
111 | $& | |
112 | </p> | |
113 | </td> | |
114 | <td> | |
115 | <p> | |
116 | Outputs what matched the whole expression. | |
117 | </p> | |
118 | </td> | |
119 | </tr> | |
120 | <tr> | |
121 | <td> | |
122 | <p> | |
123 | $MATCH | |
124 | </p> | |
125 | </td> | |
126 | <td> | |
127 | <p> | |
128 | As $& | |
129 | </p> | |
130 | </td> | |
131 | </tr> | |
132 | <tr> | |
133 | <td> | |
134 | <p> | |
135 | ${^MATCH} | |
136 | </p> | |
137 | </td> | |
138 | <td> | |
139 | <p> | |
140 | As $& | |
141 | </p> | |
142 | </td> | |
143 | </tr> | |
144 | <tr> | |
145 | <td> | |
146 | <p> | |
147 | $` | |
148 | </p> | |
149 | </td> | |
150 | <td> | |
151 | <p> | |
152 | Outputs the text between the end of the last match found (or the | |
153 | start of the text if no previous match was found), and the start | |
154 | of the current match. | |
155 | </p> | |
156 | </td> | |
157 | </tr> | |
158 | <tr> | |
159 | <td> | |
160 | <p> | |
161 | $PREMATCH | |
162 | </p> | |
163 | </td> | |
164 | <td> | |
165 | <p> | |
166 | As $` | |
167 | </p> | |
168 | </td> | |
169 | </tr> | |
170 | <tr> | |
171 | <td> | |
172 | <p> | |
173 | ${^PREMATCH} | |
174 | </p> | |
175 | </td> | |
176 | <td> | |
177 | <p> | |
178 | As $` | |
179 | </p> | |
180 | </td> | |
181 | </tr> | |
182 | <tr> | |
183 | <td> | |
184 | <p> | |
185 | $' | |
186 | </p> | |
187 | </td> | |
188 | <td> | |
189 | <p> | |
190 | Outputs all the text following the end of the current match. | |
191 | </p> | |
192 | </td> | |
193 | </tr> | |
194 | <tr> | |
195 | <td> | |
196 | <p> | |
197 | $POSTMATCH | |
198 | </p> | |
199 | </td> | |
200 | <td> | |
201 | <p> | |
202 | As $' | |
203 | </p> | |
204 | </td> | |
205 | </tr> | |
206 | <tr> | |
207 | <td> | |
208 | <p> | |
209 | ${^POSTMATCH} | |
210 | </p> | |
211 | </td> | |
212 | <td> | |
213 | <p> | |
214 | As $' | |
215 | </p> | |
216 | </td> | |
217 | </tr> | |
218 | <tr> | |
219 | <td> | |
220 | <p> | |
221 | $+ | |
222 | </p> | |
223 | </td> | |
224 | <td> | |
225 | <p> | |
226 | Outputs what matched the last marked sub-expression in the regular | |
227 | expression. | |
228 | </p> | |
229 | </td> | |
230 | </tr> | |
231 | <tr> | |
232 | <td> | |
233 | <p> | |
234 | $LAST_PAREN_MATCH | |
235 | </p> | |
236 | </td> | |
237 | <td> | |
238 | <p> | |
239 | As $+ | |
240 | </p> | |
241 | </td> | |
242 | </tr> | |
243 | <tr> | |
244 | <td> | |
245 | <p> | |
246 | $LAST_SUBMATCH_RESULT | |
247 | </p> | |
248 | </td> | |
249 | <td> | |
250 | <p> | |
251 | Outputs what matched the last sub-expression to be actually matched. | |
252 | </p> | |
253 | </td> | |
254 | </tr> | |
255 | <tr> | |
256 | <td> | |
257 | <p> | |
258 | $^N | |
259 | </p> | |
260 | </td> | |
261 | <td> | |
262 | <p> | |
263 | As $LAST_SUBMATCH_RESULT | |
264 | </p> | |
265 | </td> | |
266 | </tr> | |
267 | <tr> | |
268 | <td> | |
269 | <p> | |
270 | $$ | |
271 | </p> | |
272 | </td> | |
273 | <td> | |
274 | <p> | |
275 | Outputs a literal '$' | |
276 | </p> | |
277 | </td> | |
278 | </tr> | |
279 | <tr> | |
280 | <td> | |
281 | <p> | |
282 | $n | |
283 | </p> | |
284 | </td> | |
285 | <td> | |
286 | <p> | |
287 | Outputs what matched the n'th sub-expression. | |
288 | </p> | |
289 | </td> | |
290 | </tr> | |
291 | <tr> | |
292 | <td> | |
293 | <p> | |
294 | ${n} | |
295 | </p> | |
296 | </td> | |
297 | <td> | |
298 | <p> | |
299 | Outputs what matched the n'th sub-expression. | |
300 | </p> | |
301 | </td> | |
302 | </tr> | |
303 | <tr> | |
304 | <td> | |
305 | <p> | |
306 | $+{NAME} | |
307 | </p> | |
308 | </td> | |
309 | <td> | |
310 | <p> | |
311 | Outputs whatever matched the sub-expression named "NAME". | |
312 | </p> | |
313 | </td> | |
314 | </tr> | |
315 | </tbody> | |
316 | </table></div> | |
317 | <p> | |
318 | Any $-placeholder sequence not listed above, results in '$' being treated | |
319 | as a literal. | |
320 | </p> | |
321 | <h5> | |
322 | <a name="boost_regex.format.boost_format_syntax.h3"></a> | |
323 | <span class="phrase"><a name="boost_regex.format.boost_format_syntax.escape_sequences"></a></span><a class="link" href="boost_format_syntax.html#boost_regex.format.boost_format_syntax.escape_sequences">Escape | |
324 | Sequences</a> | |
325 | </h5> | |
326 | <p> | |
327 | An escape character followed by any character x, outputs that character unless | |
328 | x is one of the escape sequences shown below. | |
329 | </p> | |
330 | <div class="informaltable"><table class="table"> | |
331 | <colgroup> | |
332 | <col> | |
333 | <col> | |
334 | </colgroup> | |
335 | <thead><tr> | |
336 | <th> | |
337 | <p> | |
338 | Escape | |
339 | </p> | |
340 | </th> | |
341 | <th> | |
342 | <p> | |
343 | Meaning | |
344 | </p> | |
345 | </th> | |
346 | </tr></thead> | |
347 | <tbody> | |
348 | <tr> | |
349 | <td> | |
350 | <p> | |
351 | \a | |
352 | </p> | |
353 | </td> | |
354 | <td> | |
355 | <p> | |
356 | Outputs the bell character: '\a'. | |
357 | </p> | |
358 | </td> | |
359 | </tr> | |
360 | <tr> | |
361 | <td> | |
362 | <p> | |
363 | \e | |
364 | </p> | |
365 | </td> | |
366 | <td> | |
367 | <p> | |
368 | Outputs the ANSI escape character (code point 27). | |
369 | </p> | |
370 | </td> | |
371 | </tr> | |
372 | <tr> | |
373 | <td> | |
374 | <p> | |
375 | \f | |
376 | </p> | |
377 | </td> | |
378 | <td> | |
379 | <p> | |
380 | Outputs a form feed character: '\f' | |
381 | </p> | |
382 | </td> | |
383 | </tr> | |
384 | <tr> | |
385 | <td> | |
386 | <p> | |
387 | \n | |
388 | </p> | |
389 | </td> | |
390 | <td> | |
391 | <p> | |
392 | Outputs a newline character: '\n'. | |
393 | </p> | |
394 | </td> | |
395 | </tr> | |
396 | <tr> | |
397 | <td> | |
398 | <p> | |
399 | \r | |
400 | </p> | |
401 | </td> | |
402 | <td> | |
403 | <p> | |
404 | Outputs a carriage return character: '\r'. | |
405 | </p> | |
406 | </td> | |
407 | </tr> | |
408 | <tr> | |
409 | <td> | |
410 | <p> | |
411 | \t | |
412 | </p> | |
413 | </td> | |
414 | <td> | |
415 | <p> | |
416 | Outputs a tab character: '\t'. | |
417 | </p> | |
418 | </td> | |
419 | </tr> | |
420 | <tr> | |
421 | <td> | |
422 | <p> | |
423 | \v | |
424 | </p> | |
425 | </td> | |
426 | <td> | |
427 | <p> | |
428 | Outputs a vertical tab character: '\v'. | |
429 | </p> | |
430 | </td> | |
431 | </tr> | |
432 | <tr> | |
433 | <td> | |
434 | <p> | |
435 | \xDD | |
436 | </p> | |
437 | </td> | |
438 | <td> | |
439 | <p> | |
440 | Outputs the character whose hexadecimal code point is 0xDD | |
441 | </p> | |
442 | </td> | |
443 | </tr> | |
444 | <tr> | |
445 | <td> | |
446 | <p> | |
447 | \x{DDDD} | |
448 | </p> | |
449 | </td> | |
450 | <td> | |
451 | <p> | |
452 | Outputs the character whose hexadecimal code point is 0xDDDDD | |
453 | </p> | |
454 | </td> | |
455 | </tr> | |
456 | <tr> | |
457 | <td> | |
458 | <p> | |
459 | \cX | |
460 | </p> | |
461 | </td> | |
462 | <td> | |
463 | <p> | |
464 | Outputs the ANSI escape sequence "escape-X". | |
465 | </p> | |
466 | </td> | |
467 | </tr> | |
468 | <tr> | |
469 | <td> | |
470 | <p> | |
471 | \D | |
472 | </p> | |
473 | </td> | |
474 | <td> | |
475 | <p> | |
476 | If D is a decimal digit in the range 1-9, then outputs the text | |
477 | that matched sub-expression D. | |
478 | </p> | |
479 | </td> | |
480 | </tr> | |
481 | <tr> | |
482 | <td> | |
483 | <p> | |
484 | \l | |
485 | </p> | |
486 | </td> | |
487 | <td> | |
488 | <p> | |
489 | Causes the next character to be outputted, to be output in lower | |
490 | case. | |
491 | </p> | |
492 | </td> | |
493 | </tr> | |
494 | <tr> | |
495 | <td> | |
496 | <p> | |
497 | \u | |
498 | </p> | |
499 | </td> | |
500 | <td> | |
501 | <p> | |
502 | Causes the next character to be outputted, to be output in upper | |
503 | case. | |
504 | </p> | |
505 | </td> | |
506 | </tr> | |
507 | <tr> | |
508 | <td> | |
509 | <p> | |
510 | \L | |
511 | </p> | |
512 | </td> | |
513 | <td> | |
514 | <p> | |
515 | Causes all subsequent characters to be output in lower case, until | |
516 | a \E is found. | |
517 | </p> | |
518 | </td> | |
519 | </tr> | |
520 | <tr> | |
521 | <td> | |
522 | <p> | |
523 | \U | |
524 | </p> | |
525 | </td> | |
526 | <td> | |
527 | <p> | |
528 | Causes all subsequent characters to be output in upper case, until | |
529 | a \E is found. | |
530 | </p> | |
531 | </td> | |
532 | </tr> | |
533 | <tr> | |
534 | <td> | |
535 | <p> | |
536 | \E | |
537 | </p> | |
538 | </td> | |
539 | <td> | |
540 | <p> | |
541 | Terminates a \L or \U sequence. | |
542 | </p> | |
543 | </td> | |
544 | </tr> | |
545 | </tbody> | |
546 | </table></div> | |
547 | </div> | |
548 | <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> | |
549 | <td align="left"></td> | |
550 | <td align="right"><div class="copyright-footer">Copyright © 1998-2013 John Maddock<p> | |
551 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
552 | 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>) | |
553 | </p> | |
554 | </div></td> | |
555 | </tr></table> | |
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