/[pcre]/code/trunk/doc/html/pcresyntax.html
ViewVC logotype

Contents of /code/trunk/doc/html/pcresyntax.html

Parent Directory Parent Directory | Revision Log Revision Log


Revision 1502 - (show annotations)
Mon Sep 15 13:56:18 2014 UTC (10 months, 2 weeks ago) by ph10
File MIME type: text/html
File size: 16694 byte(s)
Error occurred while calculating annotation data.
Files tidied for 8.36-RC1.
1 <html>
2 <head>
3 <title>pcresyntax specification</title>
4 </head>
5 <body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
6 <h1>pcresyntax man page</h1>
7 <p>
8 Return to the <a href="index.html">PCRE index page</a>.
9 </p>
10 <p>
11 This page is part of the PCRE HTML documentation. It was generated automatically
12 from the original man page. If there is any nonsense in it, please consult the
13 man page, in case the conversion went wrong.
14 <br>
15 <ul>
16 <li><a name="TOC1" href="#SEC1">PCRE REGULAR EXPRESSION SYNTAX SUMMARY</a>
17 <li><a name="TOC2" href="#SEC2">QUOTING</a>
18 <li><a name="TOC3" href="#SEC3">CHARACTERS</a>
19 <li><a name="TOC4" href="#SEC4">CHARACTER TYPES</a>
20 <li><a name="TOC5" href="#SEC5">GENERAL CATEGORY PROPERTIES FOR \p and \P</a>
21 <li><a name="TOC6" href="#SEC6">PCRE SPECIAL CATEGORY PROPERTIES FOR \p and \P</a>
22 <li><a name="TOC7" href="#SEC7">SCRIPT NAMES FOR \p AND \P</a>
23 <li><a name="TOC8" href="#SEC8">CHARACTER CLASSES</a>
24 <li><a name="TOC9" href="#SEC9">QUANTIFIERS</a>
25 <li><a name="TOC10" href="#SEC10">ANCHORS AND SIMPLE ASSERTIONS</a>
26 <li><a name="TOC11" href="#SEC11">MATCH POINT RESET</a>
27 <li><a name="TOC12" href="#SEC12">ALTERNATION</a>
28 <li><a name="TOC13" href="#SEC13">CAPTURING</a>
29 <li><a name="TOC14" href="#SEC14">ATOMIC GROUPS</a>
30 <li><a name="TOC15" href="#SEC15">COMMENT</a>
31 <li><a name="TOC16" href="#SEC16">OPTION SETTING</a>
32 <li><a name="TOC17" href="#SEC17">NEWLINE CONVENTION</a>
33 <li><a name="TOC18" href="#SEC18">WHAT \R MATCHES</a>
34 <li><a name="TOC19" href="#SEC19">LOOKAHEAD AND LOOKBEHIND ASSERTIONS</a>
35 <li><a name="TOC20" href="#SEC20">BACKREFERENCES</a>
36 <li><a name="TOC21" href="#SEC21">SUBROUTINE REFERENCES (POSSIBLY RECURSIVE)</a>
37 <li><a name="TOC22" href="#SEC22">CONDITIONAL PATTERNS</a>
38 <li><a name="TOC23" href="#SEC23">BACKTRACKING CONTROL</a>
39 <li><a name="TOC24" href="#SEC24">CALLOUTS</a>
40 <li><a name="TOC25" href="#SEC25">SEE ALSO</a>
41 <li><a name="TOC26" href="#SEC26">AUTHOR</a>
42 <li><a name="TOC27" href="#SEC27">REVISION</a>
43 </ul>
44 <br><a name="SEC1" href="#TOC1">PCRE REGULAR EXPRESSION SYNTAX SUMMARY</a><br>
45 <P>
46 The full syntax and semantics of the regular expressions that are supported by
47 PCRE are described in the
48 <a href="pcrepattern.html"><b>pcrepattern</b></a>
49 documentation. This document contains a quick-reference summary of the syntax.
50 </P>
51 <br><a name="SEC2" href="#TOC1">QUOTING</a><br>
52 <P>
53 <pre>
54 \x where x is non-alphanumeric is a literal x
55 \Q...\E treat enclosed characters as literal
56 </PRE>
57 </P>
58 <br><a name="SEC3" href="#TOC1">CHARACTERS</a><br>
59 <P>
60 <pre>
61 \a alarm, that is, the BEL character (hex 07)
62 \cx "control-x", where x is any ASCII character
63 \e escape (hex 1B)
64 \f form feed (hex 0C)
65 \n newline (hex 0A)
66 \r carriage return (hex 0D)
67 \t tab (hex 09)
68 \0dd character with octal code 0dd
69 \ddd character with octal code ddd, or backreference
70 \o{ddd..} character with octal code ddd..
71 \xhh character with hex code hh
72 \x{hhh..} character with hex code hhh..
73 </pre>
74 Note that \0dd is always an octal code, and that \8 and \9 are the literal
75 characters "8" and "9".
76 </P>
77 <br><a name="SEC4" href="#TOC1">CHARACTER TYPES</a><br>
78 <P>
79 <pre>
80 . any character except newline;
81 in dotall mode, any character whatsoever
82 \C one data unit, even in UTF mode (best avoided)
83 \d a decimal digit
84 \D a character that is not a decimal digit
85 \h a horizontal white space character
86 \H a character that is not a horizontal white space character
87 \N a character that is not a newline
88 \p{<i>xx</i>} a character with the <i>xx</i> property
89 \P{<i>xx</i>} a character without the <i>xx</i> property
90 \R a newline sequence
91 \s a white space character
92 \S a character that is not a white space character
93 \v a vertical white space character
94 \V a character that is not a vertical white space character
95 \w a "word" character
96 \W a "non-word" character
97 \X a Unicode extended grapheme cluster
98 </pre>
99 By default, \d, \s, and \w match only ASCII characters, even in UTF-8 mode
100 or in the 16- bit and 32-bit libraries. However, if locale-specific matching is
101 happening, \s and \w may also match characters with code points in the range
102 128-255. If the PCRE_UCP option is set, the behaviour of these escape sequences
103 is changed to use Unicode properties and they match many more characters.
104 </P>
105 <br><a name="SEC5" href="#TOC1">GENERAL CATEGORY PROPERTIES FOR \p and \P</a><br>
106 <P>
107 <pre>
108 C Other
109 Cc Control
110 Cf Format
111 Cn Unassigned
112 Co Private use
113 Cs Surrogate
114
115 L Letter
116 Ll Lower case letter
117 Lm Modifier letter
118 Lo Other letter
119 Lt Title case letter
120 Lu Upper case letter
121 L& Ll, Lu, or Lt
122
123 M Mark
124 Mc Spacing mark
125 Me Enclosing mark
126 Mn Non-spacing mark
127
128 N Number
129 Nd Decimal number
130 Nl Letter number
131 No Other number
132
133 P Punctuation
134 Pc Connector punctuation
135 Pd Dash punctuation
136 Pe Close punctuation
137 Pf Final punctuation
138 Pi Initial punctuation
139 Po Other punctuation
140 Ps Open punctuation
141
142 S Symbol
143 Sc Currency symbol
144 Sk Modifier symbol
145 Sm Mathematical symbol
146 So Other symbol
147
148 Z Separator
149 Zl Line separator
150 Zp Paragraph separator
151 Zs Space separator
152 </PRE>
153 </P>
154 <br><a name="SEC6" href="#TOC1">PCRE SPECIAL CATEGORY PROPERTIES FOR \p and \P</a><br>
155 <P>
156 <pre>
157 Xan Alphanumeric: union of properties L and N
158 Xps POSIX space: property Z or tab, NL, VT, FF, CR
159 Xsp Perl space: property Z or tab, NL, VT, FF, CR
160 Xuc Univerally-named character: one that can be
161 represented by a Universal Character Name
162 Xwd Perl word: property Xan or underscore
163 </pre>
164 Perl and POSIX space are now the same. Perl added VT to its space character set
165 at release 5.18 and PCRE changed at release 8.34.
166 </P>
167 <br><a name="SEC7" href="#TOC1">SCRIPT NAMES FOR \p AND \P</a><br>
168 <P>
169 Arabic,
170 Armenian,
171 Avestan,
172 Balinese,
173 Bamum,
174 Bassa_Vah,
175 Batak,
176 Bengali,
177 Bopomofo,
178 Brahmi,
179 Braille,
180 Buginese,
181 Buhid,
182 Canadian_Aboriginal,
183 Carian,
184 Caucasian_Albanian,
185 Chakma,
186 Cham,
187 Cherokee,
188 Common,
189 Coptic,
190 Cuneiform,
191 Cypriot,
192 Cyrillic,
193 Deseret,
194 Devanagari,
195 Duployan,
196 Egyptian_Hieroglyphs,
197 Elbasan,
198 Ethiopic,
199 Georgian,
200 Glagolitic,
201 Gothic,
202 Grantha,
203 Greek,
204 Gujarati,
205 Gurmukhi,
206 Han,
207 Hangul,
208 Hanunoo,
209 Hebrew,
210 Hiragana,
211 Imperial_Aramaic,
212 Inherited,
213 Inscriptional_Pahlavi,
214 Inscriptional_Parthian,
215 Javanese,
216 Kaithi,
217 Kannada,
218 Katakana,
219 Kayah_Li,
220 Kharoshthi,
221 Khmer,
222 Khojki,
223 Khudawadi,
224 Lao,
225 Latin,
226 Lepcha,
227 Limbu,
228 Linear_A,
229 Linear_B,
230 Lisu,
231 Lycian,
232 Lydian,
233 Mahajani,
234 Malayalam,
235 Mandaic,
236 Manichaean,
237 Meetei_Mayek,
238 Mende_Kikakui,
239 Meroitic_Cursive,
240 Meroitic_Hieroglyphs,
241 Miao,
242 Modi,
243 Mongolian,
244 Mro,
245 Myanmar,
246 Nabataean,
247 New_Tai_Lue,
248 Nko,
249 Ogham,
250 Ol_Chiki,
251 Old_Italic,
252 Old_North_Arabian,
253 Old_Permic,
254 Old_Persian,
255 Old_South_Arabian,
256 Old_Turkic,
257 Oriya,
258 Osmanya,
259 Pahawh_Hmong,
260 Palmyrene,
261 Pau_Cin_Hau,
262 Phags_Pa,
263 Phoenician,
264 Psalter_Pahlavi,
265 Rejang,
266 Runic,
267 Samaritan,
268 Saurashtra,
269 Sharada,
270 Shavian,
271 Siddham,
272 Sinhala,
273 Sora_Sompeng,
274 Sundanese,
275 Syloti_Nagri,
276 Syriac,
277 Tagalog,
278 Tagbanwa,
279 Tai_Le,
280 Tai_Tham,
281 Tai_Viet,
282 Takri,
283 Tamil,
284 Telugu,
285 Thaana,
286 Thai,
287 Tibetan,
288 Tifinagh,
289 Tirhuta,
290 Ugaritic,
291 Vai,
292 Warang_Citi,
293 Yi.
294 </P>
295 <br><a name="SEC8" href="#TOC1">CHARACTER CLASSES</a><br>
296 <P>
297 <pre>
298 [...] positive character class
299 [^...] negative character class
300 [x-y] range (can be used for hex characters)
301 [[:xxx:]] positive POSIX named set
302 [[:^xxx:]] negative POSIX named set
303
304 alnum alphanumeric
305 alpha alphabetic
306 ascii 0-127
307 blank space or tab
308 cntrl control character
309 digit decimal digit
310 graph printing, excluding space
311 lower lower case letter
312 print printing, including space
313 punct printing, excluding alphanumeric
314 space white space
315 upper upper case letter
316 word same as \w
317 xdigit hexadecimal digit
318 </pre>
319 In PCRE, POSIX character set names recognize only ASCII characters by default,
320 but some of them use Unicode properties if PCRE_UCP is set. You can use
321 \Q...\E inside a character class.
322 </P>
323 <br><a name="SEC9" href="#TOC1">QUANTIFIERS</a><br>
324 <P>
325 <pre>
326 ? 0 or 1, greedy
327 ?+ 0 or 1, possessive
328 ?? 0 or 1, lazy
329 * 0 or more, greedy
330 *+ 0 or more, possessive
331 *? 0 or more, lazy
332 + 1 or more, greedy
333 ++ 1 or more, possessive
334 +? 1 or more, lazy
335 {n} exactly n
336 {n,m} at least n, no more than m, greedy
337 {n,m}+ at least n, no more than m, possessive
338 {n,m}? at least n, no more than m, lazy
339 {n,} n or more, greedy
340 {n,}+ n or more, possessive
341 {n,}? n or more, lazy
342 </PRE>
343 </P>
344 <br><a name="SEC10" href="#TOC1">ANCHORS AND SIMPLE ASSERTIONS</a><br>
345 <P>
346 <pre>
347 \b word boundary
348 \B not a word boundary
349 ^ start of subject
350 also after internal newline in multiline mode
351 \A start of subject
352 $ end of subject
353 also before newline at end of subject
354 also before internal newline in multiline mode
355 \Z end of subject
356 also before newline at end of subject
357 \z end of subject
358 \G first matching position in subject
359 </PRE>
360 </P>
361 <br><a name="SEC11" href="#TOC1">MATCH POINT RESET</a><br>
362 <P>
363 <pre>
364 \K reset start of match
365 </pre>
366 \K is honoured in positive assertions, but ignored in negative ones.
367 </P>
368 <br><a name="SEC12" href="#TOC1">ALTERNATION</a><br>
369 <P>
370 <pre>
371 expr|expr|expr...
372 </PRE>
373 </P>
374 <br><a name="SEC13" href="#TOC1">CAPTURING</a><br>
375 <P>
376 <pre>
377 (...) capturing group
378 (?&#60;name&#62;...) named capturing group (Perl)
379 (?'name'...) named capturing group (Perl)
380 (?P&#60;name&#62;...) named capturing group (Python)
381 (?:...) non-capturing group
382 (?|...) non-capturing group; reset group numbers for
383 capturing groups in each alternative
384 </PRE>
385 </P>
386 <br><a name="SEC14" href="#TOC1">ATOMIC GROUPS</a><br>
387 <P>
388 <pre>
389 (?&#62;...) atomic, non-capturing group
390 </PRE>
391 </P>
392 <br><a name="SEC15" href="#TOC1">COMMENT</a><br>
393 <P>
394 <pre>
395 (?#....) comment (not nestable)
396 </PRE>
397 </P>
398 <br><a name="SEC16" href="#TOC1">OPTION SETTING</a><br>
399 <P>
400 <pre>
401 (?i) caseless
402 (?J) allow duplicate names
403 (?m) multiline
404 (?s) single line (dotall)
405 (?U) default ungreedy (lazy)
406 (?x) extended (ignore white space)
407 (?-...) unset option(s)
408 </pre>
409 The following are recognized only at the very start of a pattern or after one
410 of the newline or \R options with similar syntax. More than one of them may
411 appear.
412 <pre>
413 (*LIMIT_MATCH=d) set the match limit to d (decimal number)
414 (*LIMIT_RECURSION=d) set the recursion limit to d (decimal number)
415 (*NO_AUTO_POSSESS) no auto-possessification (PCRE_NO_AUTO_POSSESS)
416 (*NO_START_OPT) no start-match optimization (PCRE_NO_START_OPTIMIZE)
417 (*UTF8) set UTF-8 mode: 8-bit library (PCRE_UTF8)
418 (*UTF16) set UTF-16 mode: 16-bit library (PCRE_UTF16)
419 (*UTF32) set UTF-32 mode: 32-bit library (PCRE_UTF32)
420 (*UTF) set appropriate UTF mode for the library in use
421 (*UCP) set PCRE_UCP (use Unicode properties for \d etc)
422 </pre>
423 Note that LIMIT_MATCH and LIMIT_RECURSION can only reduce the value of the
424 limits set by the caller of pcre_exec(), not increase them.
425 </P>
426 <br><a name="SEC17" href="#TOC1">NEWLINE CONVENTION</a><br>
427 <P>
428 These are recognized only at the very start of the pattern or after option
429 settings with a similar syntax.
430 <pre>
431 (*CR) carriage return only
432 (*LF) linefeed only
433 (*CRLF) carriage return followed by linefeed
434 (*ANYCRLF) all three of the above
435 (*ANY) any Unicode newline sequence
436 </PRE>
437 </P>
438 <br><a name="SEC18" href="#TOC1">WHAT \R MATCHES</a><br>
439 <P>
440 These are recognized only at the very start of the pattern or after option
441 setting with a similar syntax.
442 <pre>
443 (*BSR_ANYCRLF) CR, LF, or CRLF
444 (*BSR_UNICODE) any Unicode newline sequence
445 </PRE>
446 </P>
447 <br><a name="SEC19" href="#TOC1">LOOKAHEAD AND LOOKBEHIND ASSERTIONS</a><br>
448 <P>
449 <pre>
450 (?=...) positive look ahead
451 (?!...) negative look ahead
452 (?&#60;=...) positive look behind
453 (?&#60;!...) negative look behind
454 </pre>
455 Each top-level branch of a look behind must be of a fixed length.
456 </P>
457 <br><a name="SEC20" href="#TOC1">BACKREFERENCES</a><br>
458 <P>
459 <pre>
460 \n reference by number (can be ambiguous)
461 \gn reference by number
462 \g{n} reference by number
463 \g{-n} relative reference by number
464 \k&#60;name&#62; reference by name (Perl)
465 \k'name' reference by name (Perl)
466 \g{name} reference by name (Perl)
467 \k{name} reference by name (.NET)
468 (?P=name) reference by name (Python)
469 </PRE>
470 </P>
471 <br><a name="SEC21" href="#TOC1">SUBROUTINE REFERENCES (POSSIBLY RECURSIVE)</a><br>
472 <P>
473 <pre>
474 (?R) recurse whole pattern
475 (?n) call subpattern by absolute number
476 (?+n) call subpattern by relative number
477 (?-n) call subpattern by relative number
478 (?&name) call subpattern by name (Perl)
479 (?P&#62;name) call subpattern by name (Python)
480 \g&#60;name&#62; call subpattern by name (Oniguruma)
481 \g'name' call subpattern by name (Oniguruma)
482 \g&#60;n&#62; call subpattern by absolute number (Oniguruma)
483 \g'n' call subpattern by absolute number (Oniguruma)
484 \g&#60;+n&#62; call subpattern by relative number (PCRE extension)
485 \g'+n' call subpattern by relative number (PCRE extension)
486 \g&#60;-n&#62; call subpattern by relative number (PCRE extension)
487 \g'-n' call subpattern by relative number (PCRE extension)
488 </PRE>
489 </P>
490 <br><a name="SEC22" href="#TOC1">CONDITIONAL PATTERNS</a><br>
491 <P>
492 <pre>
493 (?(condition)yes-pattern)
494 (?(condition)yes-pattern|no-pattern)
495
496 (?(n)... absolute reference condition
497 (?(+n)... relative reference condition
498 (?(-n)... relative reference condition
499 (?(&#60;name&#62;)... named reference condition (Perl)
500 (?('name')... named reference condition (Perl)
501 (?(name)... named reference condition (PCRE)
502 (?(R)... overall recursion condition
503 (?(Rn)... specific group recursion condition
504 (?(R&name)... specific recursion condition
505 (?(DEFINE)... define subpattern for reference
506 (?(assert)... assertion condition
507 </PRE>
508 </P>
509 <br><a name="SEC23" href="#TOC1">BACKTRACKING CONTROL</a><br>
510 <P>
511 The following act immediately they are reached:
512 <pre>
513 (*ACCEPT) force successful match
514 (*FAIL) force backtrack; synonym (*F)
515 (*MARK:NAME) set name to be passed back; synonym (*:NAME)
516 </pre>
517 The following act only when a subsequent match failure causes a backtrack to
518 reach them. They all force a match failure, but they differ in what happens
519 afterwards. Those that advance the start-of-match point do so only if the
520 pattern is not anchored.
521 <pre>
522 (*COMMIT) overall failure, no advance of starting point
523 (*PRUNE) advance to next starting character
524 (*PRUNE:NAME) equivalent to (*MARK:NAME)(*PRUNE)
525 (*SKIP) advance to current matching position
526 (*SKIP:NAME) advance to position corresponding to an earlier
527 (*MARK:NAME); if not found, the (*SKIP) is ignored
528 (*THEN) local failure, backtrack to next alternation
529 (*THEN:NAME) equivalent to (*MARK:NAME)(*THEN)
530 </PRE>
531 </P>
532 <br><a name="SEC24" href="#TOC1">CALLOUTS</a><br>
533 <P>
534 <pre>
535 (?C) callout
536 (?Cn) callout with data n
537 </PRE>
538 </P>
539 <br><a name="SEC25" href="#TOC1">SEE ALSO</a><br>
540 <P>
541 <b>pcrepattern</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3),
542 <b>pcrematching</b>(3), <b>pcre</b>(3).
543 </P>
544 <br><a name="SEC26" href="#TOC1">AUTHOR</a><br>
545 <P>
546 Philip Hazel
547 <br>
548 University Computing Service
549 <br>
550 Cambridge CB2 3QH, England.
551 <br>
552 </P>
553 <br><a name="SEC27" href="#TOC1">REVISION</a><br>
554 <P>
555 Last updated: 08 January 2014
556 <br>
557 Copyright &copy; 1997-2014 University of Cambridge.
558 <br>
559 <p>
560 Return to the <a href="index.html">PCRE index page</a>.
561 </p>

  ViewVC Help
Powered by ViewVC 1.1.5