Regexp Syntax Summary
---------------------

This is a quick-reference summary of the regular expression syntax used in Monotone.

Quoting
.......

\X
     where X is non-alphanumeric is a literal X

\Q...\E
     treat enclosed characters as literal

Characters
..........

\a
     alarm, that is, the BEL character (hex 07)

\cX
     ``control-X'', where X is any character

\e
     escape (hex 1B)

\f
     formfeed (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...

Character Types
...............

.
     any character except newline; in dotall mode, any character whatsoever

\C
     one byte, even in UTF-8 mode (best avoided)

\d
     a decimal digit

\D
     a character that is not a decimal digit

\h
     a horizontal whitespace character

\H
     a character that is not a horizontal whitespace character

\p{XX}
     a character with the XX property

\P{XX}
     a character without the XX property

\R
     a newline sequence

\s
     a whitespace character

\S
     a character that is not a whitespace character

\v
     a vertical whitespace character

\V
     a character that is not a vertical whitespace character

\w
     a ``word'' character

\W
     a ``non-word'' character

\X
     an extended Unicode sequence

\d, \D, \s, \S, \w, and \W recognize only ASCII characters.

General category property codes for \p and \P
.............................................

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

Script names for \p and \P
..........................

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.

Character Classes
.................

[...]
     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
     whitespace

upper
     upper case letter

word
     same as \w

xdigit
     hexadecimal digit

In PCRE, POSIX character set names recognize only ASCII characters. You can use \Q...\E inside a character class.

Quantifiers
...........

?
     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

Anchors and Simple Assertions
.............................

\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

Match Point Reset
.................

\K
     reset start of match

Alternation
...........

EXPR|EXPR|EXPR...

Capturing
.........

(...)
     capturing group

(?<NAME>...)
     named capturing group (like Perl)

(?'NAME'...)
     named capturing group (like Perl)

(?P<NAME>...)
     named capturing group (like Python)

(?:...)
     non-capturing group

(?|...)
     non-capturing group; reset group numbers for capturing groups in each alternative

Atomic Groups
.............

(?>...)
     atomic, non-capturing group

Comment
.......

(?#....)
     comment (not nestable)

Option Setting
..............

(?i)
     caseless

(?J)
     allow duplicate names

(?m)
     multiline

(?s)
     single line (dotall)

(?U)
     default ungreedy (lazy)

(?x)
     extended (ignore white space)

(?-...)
     unset option(s)

Lookahead and Lookbehind Assertions
...................................

(?=...)
     positive look ahead

(?!...)
     negative look ahead

(?<=...)
     positive look behind

(?<!...)
     negative look behind

Each top-level branch of a look behind must be of a fixed length.

Backreferences
..............

\N
     reference by number (can be ambiguous)

\gN
     reference by number

\g{N}
     reference by number

\g{-N}
     relative reference by number

\k<NAME>
     reference by name (like Perl)

\k'NAME'
     reference by name (like Perl)

\g{NAME}
     reference by name (like Perl)

\k{NAME}
     reference by name (like .NET)

(?P=NAME)
     reference by name (like Python)

Subroutine References (possibly recursive)
..........................................

(?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 (like Perl)

(?P>NAME)
     call subpattern by name (like Python)

Conditional Patterns
....................

(?(CONDITION)YES-PATTERN)

(?(CONDITION)YES-PATTERN|NO-PATTERN)

(?(N)...
     absolute reference condition

(?(+N)...
     relative reference condition

(?(-N)...
     relative reference condition

(?(<NAME>)...
     named reference condition (like Perl)

(?('NAME')...
     named reference condition (like Perl)

(?(NAME)...
     named reference condition (PCRE only)

(?(R)...
     overall recursion condition

(?(RN)...
     specific group recursion condition

(?(R&NAME)...
     specific recursion condition

(?(DEFINE)...
     define subpattern for reference

(?(assert)...
     assertion condition

Backtracking Control
....................

The following act immediately they are reached:

(*ACCEPT)
     force successful match

(*FAIL)
     force backtrack; synonym (*F)

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.

(*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

Newline Conventions
...................

These are recognized only at the very start of the pattern or after a (*BSR_...) option.

(*CR)

(*LF)

(*CRLF)

(*ANYCRLF)

(*ANY)

What \R Matches
...............

These are recognized only at the very start of the pattern or after a (*...) option that sets the newline convention.

(*BSR_ANYCRLF)

(*BSR_UNICODE)