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)
  \eg<name>       call subpattern by name (Oniguruma)
  \eg'name'       call subpattern by name (Oniguruma)
  \eg<n>          call subpattern by absolute number (Oniguruma)
  \eg'n'          call subpattern by absolute number (Oniguruma)
  \eg<+n>         call subpattern by relative number (PCRE extension)
  \eg'+n'         call subpattern by relative number (PCRE extension)
  \eg<-n>         call subpattern by relative number (PCRE extension)
  \eg'-n'         call subpattern by relative number (PCRE extension)
.
.
.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 the pattern or after a
(*BSR_...) option.
.sp
  (*CR)
  (*LF)
  (*CRLF)
  (*ANYCRLF)
  (*ANY)
.
.
.SH "WHAT \eR MATCHES"
.rs
.sp
These are recognized only at the very start of the pattern or after a
(*...) option that sets the newline convention.
.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: 09 April 2008
Copyright (c) 1997-2008 University of Cambridge.
.fi
1	.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	.
308	.
309	.SH "BACKREFERENCES"
310	.rs
311	.sp
312	\en reference by number (can be ambiguous)
313	\egn reference by number
314	\eg{n} reference by number
315	\eg{-n} relative reference by number
316	\ek<name> reference by name (Perl)
317	\ek'name' reference by name (Perl)
318	\eg{name} reference by name (Perl)
319	\ek{name} reference by name (.NET)
320	(?P=name) reference by name (Python)
321	.
322	.
323	.SH "SUBROUTINE REFERENCES (POSSIBLY RECURSIVE)"
324	.rs
325	.sp
326	(?R) recurse whole pattern
327	(?n) call subpattern by absolute number
328	(?+n) call subpattern by relative number
329	(?-n) call subpattern by relative number
330	(?&name) call subpattern by name (Perl)
331	(?P>name) call subpattern by name (Python)
332	\eg<name> call subpattern by name (Oniguruma)
333	\eg'name' call subpattern by name (Oniguruma)
334	\eg<n> call subpattern by absolute number (Oniguruma)
335	\eg'n' call subpattern by absolute number (Oniguruma)
336	\eg<+n> call subpattern by relative number (PCRE extension)
337	\eg'+n' call subpattern by relative number (PCRE extension)
338	\eg<-n> call subpattern by relative number (PCRE extension)
339	\eg'-n' call subpattern by relative number (PCRE extension)
340	.
341	.
342	.SH "CONDITIONAL PATTERNS"
343	.rs
344	.sp
345	(?(condition)yes-pattern)
346	(?(condition)yes-pattern\|no-pattern)
347	.sp
348	(?(n)... absolute reference condition
349	(?(+n)... relative reference condition
350	(?(-n)... relative reference condition
351	(?(<name>)... named reference condition (Perl)
352	(?('name')... named reference condition (Perl)
353	(?(name)... named reference condition (PCRE)
354	(?(R)... overall recursion condition
355	(?(Rn)... specific group recursion condition
356	(?(R&name)... specific recursion condition
357	(?(DEFINE)... define subpattern for reference
358	(?(assert)... assertion condition
359	.
360	.
361	.SH "BACKTRACKING CONTROL"
362	.rs
363	.sp
364	The following act immediately they are reached:
365	.sp
366	(*ACCEPT) force successful match
367	(FAIL) force backtrack; synonym (F)
368	.sp
369	The following act only when a subsequent match failure causes a backtrack to
370	reach them. They all force a match failure, but they differ in what happens
371	afterwards. Those that advance the start-of-match point do so only if the
372	pattern is not anchored.
373	.sp
374	(*COMMIT) overall failure, no advance of starting point
375	(*PRUNE) advance to next starting character
376	(*SKIP) advance start to current matching position
377	(*THEN) local failure, backtrack to next alternation
378	.
379	.
380	.SH "NEWLINE CONVENTIONS"
381	.rs
382	.sp
383	These are recognized only at the very start of the pattern or after a
384	(*BSR_...) option.
385	.sp
386	(*CR)
387	(*LF)
388	(*CRLF)
389	(*ANYCRLF)
390	(*ANY)
391	.
392	.
393	.SH "WHAT \eR MATCHES"
394	.rs
395	.sp
396	These are recognized only at the very start of the pattern or after a
397	(*...) option that sets the newline convention.
398	.sp
399	(*BSR_ANYCRLF)
400	(*BSR_UNICODE)
401	.
402	.
403	.SH "CALLOUTS"
404	.rs
405	.sp
406	(?C) callout
407	(?Cn) callout with data n
408	.
409	.
410	.SH "SEE ALSO"
411	.rs
412	.sp
413	\fBpcrepattern\fP(3), \fBpcreapi\fP(3), \fBpcrecallout\fP(3),
414	\fBpcrematching\fP(3), \fBpcre\fP(3).
415	.
416	.
417	.SH AUTHOR
418	.rs
419	.sp
420	.nf
421	Philip Hazel
422	University Computing Service
423	Cambridge CB2 3QH, England.
424	.fi
425	.
426	.
427	.SH REVISION
428	.rs
429	.sp
430	.nf
431	Last updated: 09 April 2008
432	Copyright (c) 1997-2008 University of Cambridge.
433	.fi