7.4.1 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)