trunk/doc/pcresyntax.3

.TH PCRESYNTAX 3
.SH NAME
PCRE - Perl-compatible regular expressions
.SH "PCRE REGULAR EXPRESSION SYNTAX SUMMARY"
.rs
.sp
The full syntax and semantics of the regular expressions that are supported by
PCRE are described in the
.\" HREF
\fBpcrepattern\fP
.\"
documentation. This document contains just a quick-reference summary of the
syntax.
.
.
.SH "QUOTING"
.rs
.sp
  \ex         where x is non-alphanumeric is a literal x
  \eQ...\eE    treat enclosed characters as literal
.
.
.SH "CHARACTERS"
.rs
.sp
  \ea         alarm, that is, the BEL character (hex 07)
  \ecx        "control-x", where x is any character
  \ee         escape (hex 1B)
  \ef         formfeed (hex 0C)
  \en         newline (hex 0A)
  \er         carriage return (hex 0D)
  \et         tab (hex 09)
  \eddd       character with octal code ddd, or backreference
  \exhh       character with hex code hh
  \ex{hhh..}  character with hex code hhh..
.
.
.SH "CHARACTER TYPES"
.rs
.sp
  .          any character except newline;
               in dotall mode, any character whatsoever
  \eC         one byte, even in UTF-8 mode (best avoided)
  \ed         a decimal digit
  \eD         a character that is not a decimal digit
  \eh         a horizontal whitespace character
  \eH         a character that is not a horizontal whitespace character
  \ep{\fIxx\fP}     a character with the \fIxx\fP property
  \eP{\fIxx\fP}     a character without the \fIxx\fP property
  \eR         a newline sequence
  \es         a whitespace character
  \eS         a character that is not a whitespace character
  \ev         a vertical whitespace character
  \eV         a character that is not a vertical whitespace character
  \ew         a "word" character
  \eW         a "non-word" character
  \eX         an extended Unicode sequence
.sp
In PCRE, \ed, \eD, \es, \eS, \ew, and \eW recognize only ASCII characters.
.
.
.SH "GENERAL CATEGORY PROPERTY CODES FOR \ep and \eP"
.rs
.sp
  C          Other
  Cc         Control
  Cf         Format
  Cn         Unassigned
  Co         Private use
  Cs         Surrogate
.sp
  L          Letter
  Ll         Lower case letter
  Lm         Modifier letter
  Lo         Other letter
  Lt         Title case letter
  Lu         Upper case letter
  L&         Ll, Lu, or Lt
.sp
  M          Mark
  Mc         Spacing mark
  Me         Enclosing mark
  Mn         Non-spacing mark
.sp
  N          Number
  Nd         Decimal number
  Nl         Letter number
  No         Other number
.sp
  P          Punctuation
  Pc         Connector punctuation
  Pd         Dash punctuation
  Pe         Close punctuation
  Pf         Final punctuation
  Pi         Initial punctuation
  Po         Other punctuation
  Ps         Open punctuation
.sp
  S          Symbol
  Sc         Currency symbol
  Sk         Modifier symbol
  Sm         Mathematical symbol
  So         Other symbol
.sp
  Z          Separator
  Zl         Line separator
  Zp         Paragraph separator
  Zs         Space separator
.
.
.SH "SCRIPT NAMES FOR \ep AND \eP"
.rs
.sp
Arabic,
Armenian,
Balinese,
Bengali,
Bopomofo,
Braille,
Buginese,
Buhid,
Canadian_Aboriginal,
Cherokee,
Common,
Coptic,
Cuneiform,
Cypriot,
Cyrillic,
Deseret,
Devanagari,
Ethiopic,
Georgian,
Glagolitic,
Gothic,
Greek,
Gujarati,
Gurmukhi,
Han,
Hangul,
Hanunoo,
Hebrew,
Hiragana,
Inherited,
Kannada,
Katakana,
Kharoshthi,
Khmer,
Lao,
Latin,
Limbu,
Linear_B,
Malayalam,
Mongolian,
Myanmar,
New_Tai_Lue,
Nko,
Ogham,
Old_Italic,
Old_Persian,
Oriya,
Osmanya,
Phags_Pa,
Phoenician,
Runic,
Shavian,
Sinhala,
Syloti_Nagri,
Syriac,
Tagalog,
Tagbanwa,
Tai_Le,
Tamil,
Telugu,
Thaana,
Thai,
Tibetan,
Tifinagh,
Ugaritic,
Yi.
.
.
.SH "CHARACTER CLASSES"
.rs
.sp
  [...]       positive character class
  [^...]      negative character class
  [x-y]       range (can be used for hex characters)
  [[:xxx:]]   positive POSIX named set
  [[^:xxx:]]  negative POSIX named set
.sp
  alnum       alphanumeric
  alpha       alphabetic
  ascii       0-127
  blank       space or tab
  cntrl       control character
  digit       decimal digit
  graph       printing, excluding space
  lower       lower case letter
  print       printing, including space
  punct       printing, excluding alphanumeric
  space       whitespace
  upper       upper case letter
  word        same as \ew
  xdigit      hexadecimal digit
.sp
In PCRE, POSIX character set names recognize only ASCII characters. You can use
\eQ...\eE inside a character class.
.
.
.SH "QUANTIFIERS"
.rs
.sp
  ?           0 or 1, greedy
  ?+          0 or 1, possessive
  ??          0 or 1, lazy
  *           0 or more, greedy
  *+          0 or more, possessive
  *?          0 or more, lazy
  +           1 or more, greedy
  ++          1 or more, possessive
  +?          1 or more, lazy
  {n}         exactly n
  {n,m}       at least n, no more than m, greedy
  {n,m}+      at least n, no more than m, possessive
  {n,m}?      at least n, no more than m, lazy
  {n,}        n or more, greedy
  {n,}+       n or more, possessive
  {n,}?       n or more, lazy
.
.
.SH "ANCHORS AND SIMPLE ASSERTIONS"
.rs
.sp
  \eb          word boundary
  \eB          not a word boundary
  ^           start of subject
               also after internal newline in multiline mode
  \eA          start of subject
  $           end of subject
               also before newline at end of subject
               also before internal newline in multiline mode
  \eZ          end of subject
               also before newline at end of subject
  \ez          end of subject
  \eG          first matching position in subject
.
.
.SH "MATCH POINT RESET"
.rs
.sp
  \eK          reset start of match
.
.
.SH "ALTERNATION"
.rs
.sp
  expr|expr|expr...
.
.
.SH "CAPTURING"
.rs
.sp
  (...)          capturing group
  (?<name>...)   named capturing group (Perl)
  (?'name'...)   named capturing group (Perl)
  (?P<name>...)  named capturing group (Python)
  (?:...)        non-capturing group
  (?|...)        non-capturing group; reset group numbers for
                  capturing groups in each alternative
.
.
.SH "ATOMIC GROUPS"
.rs
.sp
  (?>...)        atomic, non-capturing group
.
.
.
.
.SH "COMMENT"
.rs
.sp
  (?#....)       comment (not nestable)
.
.
.SH "OPTION SETTING"
.rs
.sp
  (?i)           caseless
  (?J)           allow duplicate names
  (?m)           multiline
  (?s)           single line (dotall)
  (?U)           default ungreedy (lazy)
  (?x)           extended (ignore white space)
  (?-...)        unset option(s)
.
.
.SH "LOOKAHEAD AND LOOKBEHIND ASSERTIONS"
.rs
.sp
  (?=...)        positive look ahead
  (?!...)        negative look ahead
  (?<=...)       positive look behind
  (?<!...)       negative look behind
.sp
Each top-level branch of a look behind must be of a fixed length.
.SH "BACKREFERENCES"
.rs
.sp
  \en             reference by number (can be ambiguous)
  \egn            reference by number
  \eg{n}          reference by number
  \eg{-n}         relative reference by number
  \ek<name>       reference by name (Perl)
  \ek'name'       reference by name (Perl)
  \eg{name}       reference by name (Perl)
  \ek{name}       reference by name (.NET)
  (?P=name)      reference by name (Python)
.
.
.SH "SUBROUTINE REFERENCES (POSSIBLY RECURSIVE)"
.rs
.sp
  (?R)           recurse whole pattern
  (?n)           call subpattern by absolute number
  (?+n)          call subpattern by relative number
  (?-n)          call subpattern by relative number
  (?&name)       call subpattern by name (Perl)
  (?P>name)      call subpattern by name (Python)
.
.
.SH "CONDITIONAL PATTERNS"
.rs
.sp
  (?(condition)yes-pattern)
  (?(condition)yes-pattern|no-pattern)
.sp
  (?(n)...       absolute reference condition
  (?(+n)...      relative reference condition
  (?(-n)...      relative reference condition
  (?(<name>)...  named reference condition (Perl)
  (?('name')...  named reference condition (Perl)
  (?(name)...    named reference condition (PCRE)
  (?(R)...       overall recursion condition
  (?(Rn)...      specific group recursion condition
  (?(R&name)...  specific recursion condition
  (?(DEFINE)...  define subpattern for reference
  (?(assert)...  assertion condition
.
.
.SH "BACKTRACKING CONTROL"
.rs
.sp
The following act immediately they are reached:
.sp
  (*ACCEPT)      force successful match
  (*FAIL)        force backtrack; synonym (*F)
.sp
The following act only when a subsequent match failure causes a backtrack to
reach them. They all force a match failure, but they differ in what happens
afterwards. Those that advance the start-of-match point do so only if the
pattern is not anchored.
.sp
  (*COMMIT)      overall failure, no advance of starting point
  (*PRUNE)       advance to next starting character
  (*SKIP)        advance start to current matching position
  (*THEN)        local failure, backtrack to next alternation
.
.
.SH "NEWLINE CONVENTIONS"
.rs
.sp
These are recognized only at the very start of a pattern.
.sp
  (*CR)
  (*LF)
  (*CRLF)
  (*ANYCRLF)
  (*ANY)
.
.
.SH "WHAT \eR MATCHES"
.rs
.sp
These are recognized only at the very start of a pattern.
.sp
  (*BSR_ANYCRLF)
  (*BSR_UNICODE)
.
.
.SH "CALLOUTS"
.rs
.sp
  (?C)      callout
  (?Cn)     callout with data n
.
.
.SH "SEE ALSO"
.rs
.sp
\fBpcrepattern\fP(3), \fBpcreapi\fP(3), \fBpcrecallout\fP(3),
\fBpcrematching\fP(3), \fBpcre\fP(3).
.
.
.SH AUTHOR
.rs
.sp
.nf
Philip Hazel
University Computing Service
Cambridge CB2 3QH, England.
.fi
.
.
.SH REVISION
.rs
.sp
.nf
Last updated: 11 September 2007
Copyright (c) 1997-2007 University of Cambridge.
.fi
1	ph10	208	.TH PCRESYNTAX 3
2			.SH NAME
3			PCRE - Perl-compatible regular expressions
4			.SH "PCRE REGULAR EXPRESSION SYNTAX SUMMARY"
5			.rs
6			.sp
7			The full syntax and semantics of the regular expressions that are supported by
8			PCRE are described in the
9			.\" HREF
10			\fBpcrepattern\fP
11			.\"
12			documentation. This document contains just a quick-reference summary of the
13			syntax.
14			.
15			.
16			.SH "QUOTING"
17			.rs
18			.sp
19			\ex where x is non-alphanumeric is a literal x
20			\eQ...\eE treat enclosed characters as literal
21			.
22			.
23			.SH "CHARACTERS"
24			.rs
25			.sp
26			\ea alarm, that is, the BEL character (hex 07)
27			\ecx "control-x", where x is any character
28			\ee escape (hex 1B)
29			\ef formfeed (hex 0C)
30			\en newline (hex 0A)
31			\er carriage return (hex 0D)
32			\et tab (hex 09)
33			\eddd character with octal code ddd, or backreference
34			\exhh character with hex code hh
35			\ex{hhh..} character with hex code hhh..
36			.
37			.
38			.SH "CHARACTER TYPES"
39			.rs
40			.sp
41			. any character except newline;
42			in dotall mode, any character whatsoever
43			\eC one byte, even in UTF-8 mode (best avoided)
44			\ed a decimal digit
45			\eD a character that is not a decimal digit
46			\eh a horizontal whitespace character
47			\eH a character that is not a horizontal whitespace character
48			\ep{\fIxx\fP} a character with the \fIxx\fP property
49			\eP{\fIxx\fP} a character without the \fIxx\fP property
50			\eR a newline sequence
51			\es a whitespace character
52			\eS a character that is not a whitespace character
53			\ev a vertical whitespace character
54			\eV a character that is not a vertical whitespace character
55			\ew a "word" character
56			\eW a "non-word" character
57			\eX an extended Unicode sequence
58			.sp
59			In PCRE, \ed, \eD, \es, \eS, \ew, and \eW recognize only ASCII characters.
60			.
61			.
62			.SH "GENERAL CATEGORY PROPERTY CODES FOR \ep and \eP"
63			.rs
64			.sp
65			C Other
66			Cc Control
67			Cf Format
68			Cn Unassigned
69			Co Private use
70			Cs Surrogate
71			.sp
72			L Letter
73			Ll Lower case letter
74			Lm Modifier letter
75			Lo Other letter
76			Lt Title case letter
77			Lu Upper case letter
78			L& Ll, Lu, or Lt
79			.sp
80			M Mark
81			Mc Spacing mark
82			Me Enclosing mark
83			Mn Non-spacing mark
84			.sp
85			N Number
86			Nd Decimal number
87			Nl Letter number
88			No Other number
89			.sp
90			P Punctuation
91			Pc Connector punctuation
92			Pd Dash punctuation
93			Pe Close punctuation
94			Pf Final punctuation
95			Pi Initial punctuation
96			Po Other punctuation
97			Ps Open punctuation
98			.sp
99			S Symbol
100			Sc Currency symbol
101			Sk Modifier symbol
102			Sm Mathematical symbol
103			So Other symbol
104			.sp
105			Z Separator
106			Zl Line separator
107			Zp Paragraph separator
108			Zs Space separator
109			.
110			.
111			.SH "SCRIPT NAMES FOR \ep AND \eP"
112			.rs
113			.sp
114			Arabic,
115			Armenian,
116			Balinese,
117			Bengali,
118			Bopomofo,
119			Braille,
120			Buginese,
121			Buhid,
122			Canadian_Aboriginal,
123			Cherokee,
124			Common,
125			Coptic,
126			Cuneiform,
127			Cypriot,
128			Cyrillic,
129			Deseret,
130			Devanagari,
131			Ethiopic,
132			Georgian,
133			Glagolitic,
134			Gothic,
135			Greek,
136			Gujarati,
137			Gurmukhi,
138			Han,
139			Hangul,
140			Hanunoo,
141			Hebrew,
142			Hiragana,
143			Inherited,
144			Kannada,
145			Katakana,
146			Kharoshthi,
147			Khmer,
148			Lao,
149			Latin,
150			Limbu,
151			Linear_B,
152			Malayalam,
153			Mongolian,
154			Myanmar,
155			New_Tai_Lue,
156			Nko,
157			Ogham,
158			Old_Italic,
159			Old_Persian,
160			Oriya,
161			Osmanya,
162			Phags_Pa,
163			Phoenician,
164			Runic,
165			Shavian,
166			Sinhala,
167			Syloti_Nagri,
168			Syriac,
169			Tagalog,
170			Tagbanwa,
171			Tai_Le,
172			Tamil,
173			Telugu,
174			Thaana,
175			Thai,
176			Tibetan,
177			Tifinagh,
178			Ugaritic,
179			Yi.
180			.
181			.
182			.SH "CHARACTER CLASSES"
183			.rs
184			.sp
185			[...] positive character class
186			[^...] negative character class
187			[x-y] range (can be used for hex characters)
188			[[:xxx:]] positive POSIX named set
189			[[^:xxx:]] negative POSIX named set
190			.sp
191			alnum alphanumeric
192			alpha alphabetic
193			ascii 0-127
194			blank space or tab
195			cntrl control character
196			digit decimal digit
197			graph printing, excluding space
198			lower lower case letter
199			print printing, including space
200			punct printing, excluding alphanumeric
201			space whitespace
202			upper upper case letter
203			word same as \ew
204			xdigit hexadecimal digit
205			.sp
206			In PCRE, POSIX character set names recognize only ASCII characters. You can use
207			\eQ...\eE inside a character class.
208			.
209			.
210			.SH "QUANTIFIERS"
211			.rs
212			.sp
213			? 0 or 1, greedy
214			?+ 0 or 1, possessive
215			?? 0 or 1, lazy
216			* 0 or more, greedy
217			*+ 0 or more, possessive
218			*? 0 or more, lazy
219			+ 1 or more, greedy
220			++ 1 or more, possessive
221			+? 1 or more, lazy
222			{n} exactly n
223			{n,m} at least n, no more than m, greedy
224			{n,m}+ at least n, no more than m, possessive
225			{n,m}? at least n, no more than m, lazy
226			{n,} n or more, greedy
227			{n,}+ n or more, possessive
228			{n,}? n or more, lazy
229			.
230			.
231			.SH "ANCHORS AND SIMPLE ASSERTIONS"
232			.rs
233			.sp
234			\eb word boundary
235			\eB not a word boundary
236			^ start of subject
237			also after internal newline in multiline mode
238			\eA start of subject
239			$ end of subject
240			also before newline at end of subject
241			also before internal newline in multiline mode
242			\eZ end of subject
243			also before newline at end of subject
244			\ez end of subject
245			\eG first matching position in subject
246			.
247			.
248			.SH "MATCH POINT RESET"
249			.rs
250			.sp
251			\eK reset start of match
252			.
253			.
254			.SH "ALTERNATION"
255			.rs
256			.sp
257			expr\|expr\|expr...
258			.
259			.
260			.SH "CAPTURING"
261			.rs
262			.sp
263			(...) capturing group
264			(?<name>...) named capturing group (Perl)
265			(?'name'...) named capturing group (Perl)
266			(?P<name>...) named capturing group (Python)
267			(?:...) non-capturing group
268			(?\|...) non-capturing group; reset group numbers for
269			capturing groups in each alternative
270			.
271			.
272			.SH "ATOMIC GROUPS"
273			.rs
274			.sp
275			(?>...) atomic, non-capturing group
276			.
277			.
278			.
279			.
280			.SH "COMMENT"
281			.rs
282			.sp
283			(?#....) comment (not nestable)
284			.
285			.
286			.SH "OPTION SETTING"
287			.rs
288			.sp
289			(?i) caseless
290			(?J) allow duplicate names
291			(?m) multiline
292			(?s) single line (dotall)
293			(?U) default ungreedy (lazy)
294			(?x) extended (ignore white space)
295			(?-...) unset option(s)
296			.
297			.
298			.SH "LOOKAHEAD AND LOOKBEHIND ASSERTIONS"
299			.rs
300			.sp
301			(?=...) positive look ahead
302			(?!...) negative look ahead
303			(?<=...) positive look behind
304			(?<!...) negative look behind
305			.sp
306			Each top-level branch of a look behind must be of a fixed length.
307			.SH "BACKREFERENCES"
308			.rs
309			.sp
310			\en reference by number (can be ambiguous)
311			\egn reference by number
312			\eg{n} reference by number
313			\eg{-n} relative reference by number
314			\ek<name> reference by name (Perl)
315			\ek'name' reference by name (Perl)
316			\eg{name} reference by name (Perl)
317			\ek{name} reference by name (.NET)
318			(?P=name) reference by name (Python)
319			.
320			.
321			.SH "SUBROUTINE REFERENCES (POSSIBLY RECURSIVE)"
322			.rs
323			.sp
324			(?R) recurse whole pattern
325			(?n) call subpattern by absolute number
326			(?+n) call subpattern by relative number
327			(?-n) call subpattern by relative number
328			(?&name) call subpattern by name (Perl)
329			(?P>name) call subpattern by name (Python)
330			.
331			.
332			.SH "CONDITIONAL PATTERNS"
333			.rs
334			.sp
335			(?(condition)yes-pattern)
336			(?(condition)yes-pattern\|no-pattern)
337			.sp
338			(?(n)... absolute reference condition
339			(?(+n)... relative reference condition
340			(?(-n)... relative reference condition
341			(?(<name>)... named reference condition (Perl)
342			(?('name')... named reference condition (Perl)
343			(?(name)... named reference condition (PCRE)
344			(?(R)... overall recursion condition
345			(?(Rn)... specific group recursion condition
346			(?(R&name)... specific recursion condition
347			(?(DEFINE)... define subpattern for reference
348			(?(assert)... assertion condition
349			.
350			.
351	ph10	210	.SH "BACKTRACKING CONTROL"
352			.rs
353			.sp
354	ph10	211	The following act immediately they are reached:
355			.sp
356	ph10	210	(*ACCEPT) force successful match
357			(FAIL) force backtrack; synonym (F)
358			.sp
359	ph10	211	The following act only when a subsequent match failure causes a backtrack to
360			reach them. They all force a match failure, but they differ in what happens
361			afterwards. Those that advance the start-of-match point do so only if the
362	ph10	210	pattern is not anchored.
363			.sp
364			(*COMMIT) overall failure, no advance of starting point
365			(*PRUNE) advance to next starting character
366			(*SKIP) advance start to current matching position
367			(*THEN) local failure, backtrack to next alternation
368			.
369			.
370	ph10	227	.SH "NEWLINE CONVENTIONS"
371			.rs
372			.sp
373			These are recognized only at the very start of a pattern.
374			.sp
375			(*CR)
376			(*LF)
377			(*CRLF)
378			(*ANYCRLF)
379			(*ANY)
380			.
381			.
382	ph10	231	.SH "WHAT \eR MATCHES"
383			.rs
384			.sp
385			These are recognized only at the very start of a pattern.
386			.sp
387			(*BSR_ANYCRLF)
388			(*BSR_UNICODE)
389			.
390			.
391	ph10	208	.SH "CALLOUTS"
392			.rs
393			.sp
394			(?C) callout
395			(?Cn) callout with data n
396			.
397			.
398			.SH "SEE ALSO"
399			.rs
400			.sp
401			\fBpcrepattern\fP(3), \fBpcreapi\fP(3), \fBpcrecallout\fP(3),
402			\fBpcrematching\fP(3), \fBpcre\fP(3).
403			.
404			.
405			.SH AUTHOR
406			.rs
407			.sp
408			.nf
409			Philip Hazel
410			University Computing Service
411			Cambridge CB2 3QH, England.
412			.fi
413			.
414			.
415			.SH REVISION
416			.rs
417			.sp
418			.nf
419	ph10	231	Last updated: 11 September 2007
420	ph10	208	Copyright (c) 1997-2007 University of Cambridge.
421			.fi