doc/html/pcresyntax.html

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<head>
<title>pcresyntax specification</title>
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<h1>pcresyntax man page</h1>
<p>
Return to the <a href="index.html">PCRE index page</a>.
</p>
<p>
This page is part of the PCRE HTML documentation. It was generated automatically
from the original man page. If there is any nonsense in it, please consult the
man page, in case the conversion went wrong.
<br>
<ul>
<li><a name="TOC1" href="#SEC1">PCRE REGULAR EXPRESSION SYNTAX SUMMARY</a>
<li><a name="TOC2" href="#SEC2">QUOTING</a>
<li><a name="TOC3" href="#SEC3">CHARACTERS</a>
<li><a name="TOC4" href="#SEC4">CHARACTER TYPES</a>
<li><a name="TOC5" href="#SEC5">GENERAL CATEGORY PROPERTIES FOR \p and \P</a>
<li><a name="TOC6" href="#SEC6">PCRE SPECIAL CATEGORY PROPERTIES FOR \p and \P</a>
<li><a name="TOC7" href="#SEC7">SCRIPT NAMES FOR \p AND \P</a>
<li><a name="TOC8" href="#SEC8">CHARACTER CLASSES</a>
<li><a name="TOC9" href="#SEC9">QUANTIFIERS</a>
<li><a name="TOC10" href="#SEC10">ANCHORS AND SIMPLE ASSERTIONS</a>
<li><a name="TOC11" href="#SEC11">MATCH POINT RESET</a>
<li><a name="TOC12" href="#SEC12">ALTERNATION</a>
<li><a name="TOC13" href="#SEC13">CAPTURING</a>
<li><a name="TOC14" href="#SEC14">ATOMIC GROUPS</a>
<li><a name="TOC15" href="#SEC15">COMMENT</a>
<li><a name="TOC16" href="#SEC16">OPTION SETTING</a>
<li><a name="TOC17" href="#SEC17">LOOKAHEAD AND LOOKBEHIND ASSERTIONS</a>
<li><a name="TOC18" href="#SEC18">BACKREFERENCES</a>
<li><a name="TOC19" href="#SEC19">SUBROUTINE REFERENCES (POSSIBLY RECURSIVE)</a>
<li><a name="TOC20" href="#SEC20">CONDITIONAL PATTERNS</a>
<li><a name="TOC21" href="#SEC21">BACKTRACKING CONTROL</a>
<li><a name="TOC22" href="#SEC22">NEWLINE CONVENTIONS</a>
<li><a name="TOC23" href="#SEC23">WHAT \R MATCHES</a>
<li><a name="TOC24" href="#SEC24">CALLOUTS</a>
<li><a name="TOC25" href="#SEC25">SEE ALSO</a>
<li><a name="TOC26" href="#SEC26">AUTHOR</a>
<li><a name="TOC27" href="#SEC27">REVISION</a>
</ul>
<br><a name="SEC1" href="#TOC1">PCRE REGULAR EXPRESSION SYNTAX SUMMARY</a><br>
<P>
The full syntax and semantics of the regular expressions that are supported by
PCRE are described in the
<a href="pcrepattern.html"><b>pcrepattern</b></a>
documentation. This document contains a quick-reference summary of the syntax.
</P>
<br><a name="SEC2" href="#TOC1">QUOTING</a><br>
<P>
<pre>
  \x         where x is non-alphanumeric is a literal x
  \Q...\E    treat enclosed characters as literal
</PRE>
</P>
<br><a name="SEC3" href="#TOC1">CHARACTERS</a><br>
<P>
<pre>
  \a         alarm, that is, the BEL character (hex 07)
  \cx        "control-x", where x is any ASCII character
  \e         escape (hex 1B)
  \f         form feed (hex 0C)
  \n         newline (hex 0A)
  \r         carriage return (hex 0D)
  \t         tab (hex 09)
  \ddd       character with octal code ddd, or backreference
  \xhh       character with hex code hh
  \x{hhh..}  character with hex code hhh..
</PRE>
</P>
<br><a name="SEC4" href="#TOC1">CHARACTER TYPES</a><br>
<P>
<pre>
  .          any character except newline;
               in dotall mode, any character whatsoever
  \C         one data unit, even in UTF mode (best avoided)
  \d         a decimal digit
  \D         a character that is not a decimal digit
  \h         a horizontal white space character
  \H         a character that is not a horizontal white space character
  \N         a character that is not a newline
  \p{<i>xx</i>}     a character with the <i>xx</i> property
  \P{<i>xx</i>}     a character without the <i>xx</i> property
  \R         a newline sequence
  \s         a white space character
  \S         a character that is not a white space character
  \v         a vertical white space character
  \V         a character that is not a vertical white space character
  \w         a "word" character
  \W         a "non-word" character
  \X         a Unicode extended grapheme cluster
</pre>
In PCRE, by default, \d, \D, \s, \S, \w, and \W recognize only ASCII
characters, even in a UTF mode. However, this can be changed by setting the
PCRE_UCP option.
</P>
<br><a name="SEC5" href="#TOC1">GENERAL CATEGORY PROPERTIES FOR \p and \P</a><br>
<P>
<pre>
  C          Other
  Cc         Control
  Cf         Format
  Cn         Unassigned
  Co         Private use
  Cs         Surrogate

  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

  M          Mark
  Mc         Spacing mark
  Me         Enclosing mark
  Mn         Non-spacing mark

  N          Number
  Nd         Decimal number
  Nl         Letter number
  No         Other number

  P          Punctuation
  Pc         Connector punctuation
  Pd         Dash punctuation
  Pe         Close punctuation
  Pf         Final punctuation
  Pi         Initial punctuation
  Po         Other punctuation
  Ps         Open punctuation

  S          Symbol
  Sc         Currency symbol
  Sk         Modifier symbol
  Sm         Mathematical symbol
  So         Other symbol

  Z          Separator
  Zl         Line separator
  Zp         Paragraph separator
  Zs         Space separator
</PRE>
</P>
<br><a name="SEC6" href="#TOC1">PCRE SPECIAL CATEGORY PROPERTIES FOR \p and \P</a><br>
<P>
<pre>
  Xan        Alphanumeric: union of properties L and N
  Xps        POSIX space: property Z or tab, NL, VT, FF, CR
  Xsp        Perl space: property Z or tab, NL, FF, CR
  Xuc        Univerally-named character: one that can be
               represented by a Universal Character Name
  Xwd        Perl word: property Xan or underscore
</PRE>
</P>
<br><a name="SEC7" href="#TOC1">SCRIPT NAMES FOR \p AND \P</a><br>
<P>
Arabic,
Armenian,
Avestan,
Balinese,
Bamum,
Batak,
Bengali,
Bopomofo,
Brahmi,
Braille,
Buginese,
Buhid,
Canadian_Aboriginal,
Carian,
Chakma,
Cham,
Cherokee,
Common,
Coptic,
Cuneiform,
Cypriot,
Cyrillic,
Deseret,
Devanagari,
Egyptian_Hieroglyphs,
Ethiopic,
Georgian,
Glagolitic,
Gothic,
Greek,
Gujarati,
Gurmukhi,
Han,
Hangul,
Hanunoo,
Hebrew,
Hiragana,
Imperial_Aramaic,
Inherited,
Inscriptional_Pahlavi,
Inscriptional_Parthian,
Javanese,
Kaithi,
Kannada,
Katakana,
Kayah_Li,
Kharoshthi,
Khmer,
Lao,
Latin,
Lepcha,
Limbu,
Linear_B,
Lisu,
Lycian,
Lydian,
Malayalam,
Mandaic,
Meetei_Mayek,
Meroitic_Cursive,
Meroitic_Hieroglyphs,
Miao,
Mongolian,
Myanmar,
New_Tai_Lue,
Nko,
Ogham,
Old_Italic,
Old_Persian,
Old_South_Arabian,
Old_Turkic,
Ol_Chiki,
Oriya,
Osmanya,
Phags_Pa,
Phoenician,
Rejang,
Runic,
Samaritan,
Saurashtra,
Sharada,
Shavian,
Sinhala,
Sora_Sompeng,
Sundanese,
Syloti_Nagri,
Syriac,
Tagalog,
Tagbanwa,
Tai_Le,
Tai_Tham,
Tai_Viet,
Takri,
Tamil,
Telugu,
Thaana,
Thai,
Tibetan,
Tifinagh,
Ugaritic,
Vai,
Yi.
</P>
<br><a name="SEC8" href="#TOC1">CHARACTER CLASSES</a><br>
<P>
<pre>
  [...]       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

  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       white space
  upper       upper case letter
  word        same as \w
  xdigit      hexadecimal digit
</pre>
In PCRE, POSIX character set names recognize only ASCII characters by default,
but some of them use Unicode properties if PCRE_UCP is set. You can use
\Q...\E inside a character class.
</P>
<br><a name="SEC9" href="#TOC1">QUANTIFIERS</a><br>
<P>
<pre>
  ?           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
</PRE>
</P>
<br><a name="SEC10" href="#TOC1">ANCHORS AND SIMPLE ASSERTIONS</a><br>
<P>
<pre>
  \b          word boundary
  \B          not a word boundary
  ^           start of subject
               also after internal newline in multiline mode
  \A          start of subject
  $           end of subject
               also before newline at end of subject
               also before internal newline in multiline mode
  \Z          end of subject
               also before newline at end of subject
  \z          end of subject
  \G          first matching position in subject
</PRE>
</P>
<br><a name="SEC11" href="#TOC1">MATCH POINT RESET</a><br>
<P>
<pre>
  \K          reset start of match
</PRE>
</P>
<br><a name="SEC12" href="#TOC1">ALTERNATION</a><br>
<P>
<pre>
  expr|expr|expr...
</PRE>
</P>
<br><a name="SEC13" href="#TOC1">CAPTURING</a><br>
<P>
<pre>
  (...)           capturing group
  (?&#60;name&#62;...)    named capturing group (Perl)
  (?'name'...)    named capturing group (Perl)
  (?P&#60;name&#62;...)   named capturing group (Python)
  (?:...)         non-capturing group
  (?|...)         non-capturing group; reset group numbers for
                   capturing groups in each alternative
</PRE>
</P>
<br><a name="SEC14" href="#TOC1">ATOMIC GROUPS</a><br>
<P>
<pre>
  (?&#62;...)         atomic, non-capturing group
</PRE>
</P>
<br><a name="SEC15" href="#TOC1">COMMENT</a><br>
<P>
<pre>
  (?#....)        comment (not nestable)
</PRE>
</P>
<br><a name="SEC16" href="#TOC1">OPTION SETTING</a><br>
<P>
<pre>
  (?i)            caseless
  (?J)            allow duplicate names
  (?m)            multiline
  (?s)            single line (dotall)
  (?U)            default ungreedy (lazy)
  (?x)            extended (ignore white space)
  (?-...)         unset option(s)
</pre>
The following are recognized only at the start of a pattern or after one of the
newline-setting options with similar syntax:
<pre>
  (*LIMIT_MATCH=d) set the match limit to d (decimal number)
  (*LIMIT_RECURSION=d) set the recursion limit to d (decimal number)
  (*NO_START_OPT) no start-match optimization (PCRE_NO_START_OPTIMIZE)
  (*UTF8)         set UTF-8 mode: 8-bit library (PCRE_UTF8)
  (*UTF16)        set UTF-16 mode: 16-bit library (PCRE_UTF16)
  (*UTF32)        set UTF-32 mode: 32-bit library (PCRE_UTF32)
  (*UTF)          set appropriate UTF mode for the library in use
  (*UCP)          set PCRE_UCP (use Unicode properties for \d etc)
</PRE>
</P>
<br><a name="SEC17" href="#TOC1">LOOKAHEAD AND LOOKBEHIND ASSERTIONS</a><br>
<P>
<pre>
  (?=...)         positive look ahead
  (?!...)         negative look ahead
  (?&#60;=...)        positive look behind
  (?&#60;!...)        negative look behind
</pre>
Each top-level branch of a look behind must be of a fixed length.
</P>
<br><a name="SEC18" href="#TOC1">BACKREFERENCES</a><br>
<P>
<pre>
  \n              reference by number (can be ambiguous)
  \gn             reference by number
  \g{n}           reference by number
  \g{-n}          relative reference by number
  \k&#60;name&#62;        reference by name (Perl)
  \k'name'        reference by name (Perl)
  \g{name}        reference by name (Perl)
  \k{name}        reference by name (.NET)
  (?P=name)       reference by name (Python)
</PRE>
</P>
<br><a name="SEC19" href="#TOC1">SUBROUTINE REFERENCES (POSSIBLY RECURSIVE)</a><br>
<P>
<pre>
  (?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&#62;name)       call subpattern by name (Python)
  \g&#60;name&#62;        call subpattern by name (Oniguruma)
  \g'name'        call subpattern by name (Oniguruma)
  \g&#60;n&#62;           call subpattern by absolute number (Oniguruma)
  \g'n'           call subpattern by absolute number (Oniguruma)
  \g&#60;+n&#62;          call subpattern by relative number (PCRE extension)
  \g'+n'          call subpattern by relative number (PCRE extension)
  \g&#60;-n&#62;          call subpattern by relative number (PCRE extension)
  \g'-n'          call subpattern by relative number (PCRE extension)
</PRE>
</P>
<br><a name="SEC20" href="#TOC1">CONDITIONAL PATTERNS</a><br>
<P>
<pre>
  (?(condition)yes-pattern)
  (?(condition)yes-pattern|no-pattern)

  (?(n)...        absolute reference condition
  (?(+n)...       relative reference condition
  (?(-n)...       relative reference condition
  (?(&#60;name&#62;)...   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
</PRE>
</P>
<br><a name="SEC21" href="#TOC1">BACKTRACKING CONTROL</a><br>
<P>
The following act immediately they are reached:
<pre>
  (*ACCEPT)       force successful match
  (*FAIL)         force backtrack; synonym (*F)
  (*MARK:NAME)    set name to be passed back; synonym (*:NAME)
</pre>
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.
<pre>
  (*COMMIT)       overall failure, no advance of starting point
  (*PRUNE)        advance to next starting character
  (*PRUNE:NAME)   equivalent to (*MARK:NAME)(*PRUNE)
  (*SKIP)         advance to current matching position
  (*SKIP:NAME)    advance to position corresponding to an earlier
                  (*MARK:NAME); if not found, the (*SKIP) is ignored
  (*THEN)         local failure, backtrack to next alternation
  (*THEN:NAME)    equivalent to (*MARK:NAME)(*THEN)
</PRE>
</P>
<br><a name="SEC22" href="#TOC1">NEWLINE CONVENTIONS</a><br>
<P>
These are recognized only at the very start of the pattern or after a
(*BSR_...), (*UTF8), (*UTF16), (*UTF32) or (*UCP) option.
<pre>
  (*CR)           carriage return only
  (*LF)           linefeed only
  (*CRLF)         carriage return followed by linefeed
  (*ANYCRLF)      all three of the above
  (*ANY)          any Unicode newline sequence
</PRE>
</P>
<br><a name="SEC23" href="#TOC1">WHAT \R MATCHES</a><br>
<P>
These are recognized only at the very start of the pattern or after a
(*...) option that sets the newline convention or a UTF or UCP mode.
<pre>
  (*BSR_ANYCRLF)  CR, LF, or CRLF
  (*BSR_UNICODE)  any Unicode newline sequence
</PRE>
</P>
<br><a name="SEC24" href="#TOC1">CALLOUTS</a><br>
<P>
<pre>
  (?C)      callout
  (?Cn)     callout with data n
</PRE>
</P>
<br><a name="SEC25" href="#TOC1">SEE ALSO</a><br>
<P>
<b>pcrepattern</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3),
<b>pcrematching</b>(3), <b>pcre</b>(3).
</P>
<br><a name="SEC26" href="#TOC1">AUTHOR</a><br>
<P>
Philip Hazel
<br>
University Computing Service
<br>
Cambridge CB2 3QH, England.
<br>
</P>
<br><a name="SEC27" href="#TOC1">REVISION</a><br>
<P>
Last updated: 26 April 2013
<br>
Copyright &copy; 1997-2013 University of Cambridge.
<br>
<p>
Return to the <a href="index.html">PCRE index page</a>.
</p>
1	ph10	208	<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	ph10	518	<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">LOOKAHEAD AND LOOKBEHIND ASSERTIONS</a>
33			<li><a name="TOC18" href="#SEC18">BACKREFERENCES</a>
34			<li><a name="TOC19" href="#SEC19">SUBROUTINE REFERENCES (POSSIBLY RECURSIVE)</a>
35			<li><a name="TOC20" href="#SEC20">CONDITIONAL PATTERNS</a>
36			<li><a name="TOC21" href="#SEC21">BACKTRACKING CONTROL</a>
37			<li><a name="TOC22" href="#SEC22">NEWLINE CONVENTIONS</a>
38			<li><a name="TOC23" href="#SEC23">WHAT \R MATCHES</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	ph10	208	</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	ph10	869	documentation. This document contains a quick-reference summary of the syntax.
50	ph10	208	</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	ph10	579	\cx "control-x", where x is any ASCII character
63	ph10	208	\e escape (hex 1B)
64	ph10	975	\f form feed (hex 0C)
65	ph10	208	\n newline (hex 0A)
66			\r carriage return (hex 0D)
67			\t tab (hex 09)
68			\ddd character with octal code ddd, or backreference
69			\xhh character with hex code hh
70			\x{hhh..} character with hex code hhh..
71			</PRE>
72			</P>
73			<br><a name="SEC4" href="#TOC1">CHARACTER TYPES</a><br>
74			<P>
75			<pre>
76			. any character except newline;
77			in dotall mode, any character whatsoever
78	ph10	869	\C one data unit, even in UTF mode (best avoided)
79	ph10	208	\d a decimal digit
80			\D a character that is not a decimal digit
81	ph10	975	\h a horizontal white space character
82			\H a character that is not a horizontal white space character
83	ph10	535	\N a character that is not a newline
84	ph10	208	\p{<i>xx</i>} a character with the <i>xx</i> property
85			\P{<i>xx</i>} a character without the <i>xx</i> property
86			\R a newline sequence
87	ph10	975	\s a white space character
88			\S a character that is not a white space character
89			\v a vertical white space character
90			\V a character that is not a vertical white space character
91	ph10	208	\w a "word" character
92			\W a "non-word" character
93	ph10	1194	\X a Unicode extended grapheme cluster
94	ph10	208	</pre>
95	ph10	535	In PCRE, by default, \d, \D, \s, \S, \w, and \W recognize only ASCII
96	ph10	869	characters, even in a UTF mode. However, this can be changed by setting the
97	ph10	535	PCRE_UCP option.
98	ph10	208	</P>
99	ph10	518	<br><a name="SEC5" href="#TOC1">GENERAL CATEGORY PROPERTIES FOR \p and \P</a><br>
100	ph10	208	<P>
101			<pre>
102			C Other
103			Cc Control
104			Cf Format
105			Cn Unassigned
106			Co Private use
107			Cs Surrogate
108
109			L Letter
110			Ll Lower case letter
111			Lm Modifier letter
112			Lo Other letter
113			Lt Title case letter
114			Lu Upper case letter
115			L& Ll, Lu, or Lt
116
117			M Mark
118			Mc Spacing mark
119			Me Enclosing mark
120			Mn Non-spacing mark
121
122			N Number
123			Nd Decimal number
124			Nl Letter number
125			No Other number
126
127			P Punctuation
128			Pc Connector punctuation
129			Pd Dash punctuation
130			Pe Close punctuation
131			Pf Final punctuation
132			Pi Initial punctuation
133			Po Other punctuation
134			Ps Open punctuation
135
136			S Symbol
137			Sc Currency symbol
138			Sk Modifier symbol
139			Sm Mathematical symbol
140			So Other symbol
141
142			Z Separator
143			Zl Line separator
144			Zp Paragraph separator
145			Zs Space separator
146			</PRE>
147			</P>
148	ph10	518	<br><a name="SEC6" href="#TOC1">PCRE SPECIAL CATEGORY PROPERTIES FOR \p and \P</a><br>
149	ph10	208	<P>
150	ph10	518	<pre>
151			Xan Alphanumeric: union of properties L and N
152			Xps POSIX space: property Z or tab, NL, VT, FF, CR
153			Xsp Perl space: property Z or tab, NL, FF, CR
154	ph10	1335	Xuc Univerally-named character: one that can be
155			represented by a Universal Character Name
156	ph10	535	Xwd Perl word: property Xan or underscore
157	ph10	518	</PRE>
158			</P>
159			<br><a name="SEC7" href="#TOC1">SCRIPT NAMES FOR \p AND \P</a><br>
160			<P>
161	ph10	208	Arabic,
162			Armenian,
163	ph10	507	Avestan,
164	ph10	208	Balinese,
165	ph10	507	Bamum,
166	ph10	954	Batak,
167	ph10	208	Bengali,
168			Bopomofo,
169	ph10	954	Brahmi,
170	ph10	208	Braille,
171			Buginese,
172			Buhid,
173			Canadian_Aboriginal,
174	ph10	416	Carian,
175	ph10	954	Chakma,
176	ph10	416	Cham,
177	ph10	208	Cherokee,
178			Common,
179			Coptic,
180			Cuneiform,
181			Cypriot,
182			Cyrillic,
183			Deseret,
184			Devanagari,
185	ph10	507	Egyptian_Hieroglyphs,
186	ph10	208	Ethiopic,
187			Georgian,
188			Glagolitic,
189			Gothic,
190			Greek,
191			Gujarati,
192			Gurmukhi,
193			Han,
194			Hangul,
195			Hanunoo,
196			Hebrew,
197			Hiragana,
198	ph10	507	Imperial_Aramaic,
199	ph10	208	Inherited,
200	ph10	507	Inscriptional_Pahlavi,
201			Inscriptional_Parthian,
202			Javanese,
203			Kaithi,
204	ph10	208	Kannada,
205			Katakana,
206	ph10	416	Kayah_Li,
207	ph10	208	Kharoshthi,
208			Khmer,
209			Lao,
210			Latin,
211	ph10	416	Lepcha,
212	ph10	208	Limbu,
213			Linear_B,
214	ph10	507	Lisu,
215	ph10	416	Lycian,
216			Lydian,
217	ph10	208	Malayalam,
218	ph10	954	Mandaic,
219	ph10	507	Meetei_Mayek,
220	ph10	954	Meroitic_Cursive,
221			Meroitic_Hieroglyphs,
222			Miao,
223	ph10	208	Mongolian,
224			Myanmar,
225			New_Tai_Lue,
226			Nko,
227			Ogham,
228			Old_Italic,
229			Old_Persian,
230	ph10	507	Old_South_Arabian,
231			Old_Turkic,
232	ph10	416	Ol_Chiki,
233	ph10	208	Oriya,
234			Osmanya,
235			Phags_Pa,
236			Phoenician,
237	ph10	416	Rejang,
238	ph10	208	Runic,
239	ph10	507	Samaritan,
240	ph10	416	Saurashtra,
241	ph10	954	Sharada,
242	ph10	208	Shavian,
243			Sinhala,
244	ph10	954	Sora_Sompeng,
245	ph10	507	Sundanese,
246	ph10	208	Syloti_Nagri,
247			Syriac,
248			Tagalog,
249			Tagbanwa,
250			Tai_Le,
251	ph10	507	Tai_Tham,
252			Tai_Viet,
253	ph10	954	Takri,
254	ph10	208	Tamil,
255			Telugu,
256			Thaana,
257			Thai,
258			Tibetan,
259			Tifinagh,
260			Ugaritic,
261	ph10	416	Vai,
262	ph10	208	Yi.
263			</P>
264	ph10	518	<br><a name="SEC8" href="#TOC1">CHARACTER CLASSES</a><br>
265	ph10	208	<P>
266			<pre>
267			[...] positive character class
268			[^...] negative character class
269			[x-y] range (can be used for hex characters)
270			[[:xxx:]] positive POSIX named set
271	ph10	286	[[:^xxx:]] negative POSIX named set
272	ph10	208
273			alnum alphanumeric
274			alpha alphabetic
275			ascii 0-127
276			blank space or tab
277			cntrl control character
278			digit decimal digit
279			graph printing, excluding space
280			lower lower case letter
281			print printing, including space
282			punct printing, excluding alphanumeric
283	ph10	975	space white space
284	ph10	208	upper upper case letter
285			word same as \w
286			xdigit hexadecimal digit
287			</pre>
288	ph10	535	In PCRE, POSIX character set names recognize only ASCII characters by default,
289			but some of them use Unicode properties if PCRE_UCP is set. You can use
290	ph10	208	\Q...\E inside a character class.
291			</P>
292	ph10	518	<br><a name="SEC9" href="#TOC1">QUANTIFIERS</a><br>
293	ph10	208	<P>
294			<pre>
295			? 0 or 1, greedy
296			?+ 0 or 1, possessive
297			?? 0 or 1, lazy
298			* 0 or more, greedy
299			*+ 0 or more, possessive
300			*? 0 or more, lazy
301			+ 1 or more, greedy
302			++ 1 or more, possessive
303			+? 1 or more, lazy
304			{n} exactly n
305			{n,m} at least n, no more than m, greedy
306			{n,m}+ at least n, no more than m, possessive
307			{n,m}? at least n, no more than m, lazy
308			{n,} n or more, greedy
309			{n,}+ n or more, possessive
310			{n,}? n or more, lazy
311			</PRE>
312			</P>
313	ph10	518	<br><a name="SEC10" href="#TOC1">ANCHORS AND SIMPLE ASSERTIONS</a><br>
314	ph10	208	<P>
315			<pre>
316	ph10	535	\b word boundary
317	ph10	208	\B not a word boundary
318			^ start of subject
319			also after internal newline in multiline mode
320			\A start of subject
321			$ end of subject
322			also before newline at end of subject
323			also before internal newline in multiline mode
324			\Z end of subject
325			also before newline at end of subject
326			\z end of subject
327			\G first matching position in subject
328			</PRE>
329			</P>
330	ph10	518	<br><a name="SEC11" href="#TOC1">MATCH POINT RESET</a><br>
331	ph10	208	<P>
332			<pre>
333			\K reset start of match
334			</PRE>
335			</P>
336	ph10	518	<br><a name="SEC12" href="#TOC1">ALTERNATION</a><br>
337	ph10	208	<P>
338			<pre>
339			expr\|expr\|expr...
340			</PRE>
341			</P>
342	ph10	518	<br><a name="SEC13" href="#TOC1">CAPTURING</a><br>
343	ph10	208	<P>
344			<pre>
345	ph10	416	(...) capturing group
346			(?<name>...) named capturing group (Perl)
347			(?'name'...) named capturing group (Perl)
348			(?P<name>...) named capturing group (Python)
349			(?:...) non-capturing group
350			(?\|...) non-capturing group; reset group numbers for
351			capturing groups in each alternative
352	ph10	208	</PRE>
353			</P>
354	ph10	518	<br><a name="SEC14" href="#TOC1">ATOMIC GROUPS</a><br>
355	ph10	208	<P>
356			<pre>
357	ph10	416	(?>...) atomic, non-capturing group
358	ph10	208	</PRE>
359			</P>
360	ph10	518	<br><a name="SEC15" href="#TOC1">COMMENT</a><br>
361	ph10	208	<P>
362			<pre>
363	ph10	416	(?#....) comment (not nestable)
364	ph10	208	</PRE>
365			</P>
366	ph10	518	<br><a name="SEC16" href="#TOC1">OPTION SETTING</a><br>
367	ph10	208	<P>
368			<pre>
369	ph10	416	(?i) caseless
370			(?J) allow duplicate names
371			(?m) multiline
372			(?s) single line (dotall)
373			(?U) default ungreedy (lazy)
374			(?x) extended (ignore white space)
375			(?-...) unset option(s)
376			</pre>
377	ph10	535	The following are recognized only at the start of a pattern or after one of the
378	ph10	416	newline-setting options with similar syntax:
379			<pre>
380	ph10	1320	(*LIMIT_MATCH=d) set the match limit to d (decimal number)
381			(*LIMIT_RECURSION=d) set the recursion limit to d (decimal number)
382	ph10	579	(*NO_START_OPT) no start-match optimization (PCRE_NO_START_OPTIMIZE)
383	ph10	869	(*UTF8) set UTF-8 mode: 8-bit library (PCRE_UTF8)
384			(*UTF16) set UTF-16 mode: 16-bit library (PCRE_UTF16)
385	ph10	1194	(*UTF32) set UTF-32 mode: 32-bit library (PCRE_UTF32)
386	ph10	1221	(*UTF) set appropriate UTF mode for the library in use
387	ph10	535	(*UCP) set PCRE_UCP (use Unicode properties for \d etc)
388	ph10	208	</PRE>
389			</P>
390	ph10	518	<br><a name="SEC17" href="#TOC1">LOOKAHEAD AND LOOKBEHIND ASSERTIONS</a><br>
391	ph10	208	<P>
392			<pre>
393	ph10	416	(?=...) positive look ahead
394			(?!...) negative look ahead
395			(?<=...) positive look behind
396			(?<!...) negative look behind
397	ph10	208	</pre>
398			Each top-level branch of a look behind must be of a fixed length.
399			</P>
400	ph10	518	<br><a name="SEC18" href="#TOC1">BACKREFERENCES</a><br>
401	ph10	208	<P>
402			<pre>
403	ph10	416	\n reference by number (can be ambiguous)
404			\gn reference by number
405			\g{n} reference by number
406			\g{-n} relative reference by number
407			\k<name> reference by name (Perl)
408			\k'name' reference by name (Perl)
409			\g{name} reference by name (Perl)
410			\k{name} reference by name (.NET)
411			(?P=name) reference by name (Python)
412	ph10	208	</PRE>
413			</P>
414	ph10	518	<br><a name="SEC19" href="#TOC1">SUBROUTINE REFERENCES (POSSIBLY RECURSIVE)</a><br>
415	ph10	208	<P>
416			<pre>
417	ph10	416	(?R) recurse whole pattern
418			(?n) call subpattern by absolute number
419			(?+n) call subpattern by relative number
420			(?-n) call subpattern by relative number
421			(?&name) call subpattern by name (Perl)
422			(?P>name) call subpattern by name (Python)
423			\g<name> call subpattern by name (Oniguruma)
424			\g'name' call subpattern by name (Oniguruma)
425			\g<n> call subpattern by absolute number (Oniguruma)
426			\g'n' call subpattern by absolute number (Oniguruma)
427			\g<+n> call subpattern by relative number (PCRE extension)
428			\g'+n' call subpattern by relative number (PCRE extension)
429			\g<-n> call subpattern by relative number (PCRE extension)
430			\g'-n' call subpattern by relative number (PCRE extension)
431	ph10	208	</PRE>
432			</P>
433	ph10	518	<br><a name="SEC20" href="#TOC1">CONDITIONAL PATTERNS</a><br>
434	ph10	208	<P>
435			<pre>
436			(?(condition)yes-pattern)
437			(?(condition)yes-pattern\|no-pattern)
438
439	ph10	416	(?(n)... absolute reference condition
440			(?(+n)... relative reference condition
441			(?(-n)... relative reference condition
442			(?(<name>)... named reference condition (Perl)
443			(?('name')... named reference condition (Perl)
444			(?(name)... named reference condition (PCRE)
445			(?(R)... overall recursion condition
446			(?(Rn)... specific group recursion condition
447			(?(R&name)... specific recursion condition
448			(?(DEFINE)... define subpattern for reference
449			(?(assert)... assertion condition
450	ph10	208	</PRE>
451			</P>
452	ph10	518	<br><a name="SEC21" href="#TOC1">BACKTRACKING CONTROL</a><br>
453	ph10	208	<P>
454	ph10	211	The following act immediately they are reached:
455	ph10	208	<pre>
456	ph10	416	(*ACCEPT) force successful match
457			(FAIL) force backtrack; synonym (F)
458	ph10	869	(MARK:NAME) set name to be passed back; synonym (:NAME)
459	ph10	211	</pre>
460			The following act only when a subsequent match failure causes a backtrack to
461			reach them. They all force a match failure, but they differ in what happens
462			afterwards. Those that advance the start-of-match point do so only if the
463			pattern is not anchored.
464			<pre>
465	ph10	416	(*COMMIT) overall failure, no advance of starting point
466			(*PRUNE) advance to next starting character
467	ph10	903	(PRUNE:NAME) equivalent to (MARK:NAME)(*PRUNE)
468	ph10	869	(*SKIP) advance to current matching position
469			(*SKIP:NAME) advance to position corresponding to an earlier
470	ph10	903	(MARK:NAME); if not found, the (SKIP) is ignored
471	ph10	416	(*THEN) local failure, backtrack to next alternation
472	ph10	903	(THEN:NAME) equivalent to (MARK:NAME)(*THEN)
473	ph10	211	</PRE>
474			</P>
475	ph10	518	<br><a name="SEC22" href="#TOC1">NEWLINE CONVENTIONS</a><br>
476	ph10	211	<P>
477	ph10	261	These are recognized only at the very start of the pattern or after a
478	ph10	1194	(BSR_...), (UTF8), (UTF16), (UTF32) or (*UCP) option.
479	ph10	211	<pre>
480	ph10	416	(*CR) carriage return only
481			(*LF) linefeed only
482			(*CRLF) carriage return followed by linefeed
483			(*ANYCRLF) all three of the above
484			(*ANY) any Unicode newline sequence
485	ph10	227	</PRE>
486			</P>
487	ph10	518	<br><a name="SEC23" href="#TOC1">WHAT \R MATCHES</a><br>
488	ph10	227	<P>
489	ph10	261	These are recognized only at the very start of the pattern or after a
490	ph10	869	(*...) option that sets the newline convention or a UTF or UCP mode.
491	ph10	227	<pre>
492	ph10	416	(*BSR_ANYCRLF) CR, LF, or CRLF
493			(*BSR_UNICODE) any Unicode newline sequence
494	ph10	231	</PRE>
495			</P>
496	ph10	518	<br><a name="SEC24" href="#TOC1">CALLOUTS</a><br>
497	ph10	231	<P>
498			<pre>
499	ph10	208	(?C) callout
500			(?Cn) callout with data n
501			</PRE>
502			</P>
503	ph10	518	<br><a name="SEC25" href="#TOC1">SEE ALSO</a><br>
504	ph10	208	<P>
505			<b>pcrepattern</b>(3), <b>pcreapi</b>(3), <b>pcrecallout</b>(3),
506			<b>pcrematching</b>(3), <b>pcre</b>(3).
507			</P>
508	ph10	518	<br><a name="SEC26" href="#TOC1">AUTHOR</a><br>
509	ph10	208	<P>
510			Philip Hazel
511			<br>
512			University Computing Service
513			<br>
514			Cambridge CB2 3QH, England.
515			<br>
516			</P>
517	ph10	518	<br><a name="SEC27" href="#TOC1">REVISION</a><br>
518	ph10	208	<P>
519	ph10	1320	Last updated: 26 April 2013
520	ph10	208	<br>
521	ph10	1298	Copyright © 1997-2013 University of Cambridge.
522	ph10	208	<br>
523			<p>
524			Return to the <a href="index.html">PCRE index page</a>.
525			</p>