Engine: Oniguruma

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Languages

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Features

The following features are supported:

The following features arenot supported:

Feature: Flags

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Flags control certain aspects of the matching behavior of a pattern.

Syntax

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The following flags are supported:

i — Ignore Case. Matchescharacter classes using a case-insensitive comparison.
x — Extended Mode. Ignores whitespace in a pattern. Spaces must instead be represented by\s or\ (an escaped space).
W — ASCII-only words (when using\w,\p{Word},[[:word:]],\b, or\B)
D — ASCII-only digits (when using\d,\p{Digit},[[:digit:]])
S — ASCII-only space (when using\s,\p{Space},[[:space:]])
P — ASCII-only POSIX properties (includesW,D, andS flags)
y{?} — Changes meaning of\X,\y, and\Y in unicode mode:
- y{g} — Extended Grapheme Cluster mode
- y{w} — Word mode.

Some flags depend on options provided to Oniguruma^reference:

ONIG_SYNTAX_ONIGURUMA:
- m — Multiline. Causes thewildcard. to match newline characters.
ONIG_SYNTAX_PERL andONIG_SYNTAX_JAVA:
- m — Multiline. Causes theanchors^ and$ to match the start and end of each line (respectively), rather than the start and end of the input.
- s — Singleline. Causes thewildcard. to match newline characters.

Feature: Anchors

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Anchors match the start or end of a line.

Syntax

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^ — Matches the start of a line when them (multiline)flag is set. Otherwise, matches the start of the input.
$ — Matches the end of a line when them (multiline)flag is set. Otherwise, matches the end of the input.

Feature: Buffer Boundaries

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ABuffer Boundary is anAtom that matches the start or the end of the input. This differs slightly from^ and$ which can be affected byRegExp flags likem.

Syntax

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\A — Matches the start of the input.
\z — Matches the end of the input.
\Z — A zero-width assertion consisting of an optional newline at the end of the buffer. Equivalent to(?=\n?\z).

Feature: Word Boundaries

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AWord Boundary is anAtom that matches the start or the end of a word.

Syntax

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\b — Matches the start or the end of a word.
\B — Matches whennot at the start or the end of a word.

Feature: Text Segment Boundaries

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AText Segment Boundary is anAtom that matches the start or the end of a text segment.

Syntax

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\y — Matches the start or the end of a text segment.
\Y — Matches whennot at the start or the end of a text segment.

Feature: Continuation Escape

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AContinuation Escape is a zero-width assertion that matches either the start of the input or the start of the last match.

Syntax

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\G — Matches either the start of the input or the start of the last match.

Feature: Alternatives

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AnAlternative represents two or more branches in a pattern. If first branch of a pattern fails to match, each alternative is attempted from left to right until a match is found.

Syntax

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…|… — Matches the pattern to the left of the|. If that fails, matches the pattern to the right of|.

Feature: Wildcard

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AWildcard matches a single, non-newline character.

Syntax

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. — Matches any character except newline characters. If themflag is set then this matches any character.
- NOTE: Them-flag in Oniguruma is equivalent to thes-flag (i.e., dot all) in Perl, ECMAScript, .NET, etc.

Feature: Character Classes

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ACharacter Class is anAtom that specifies a set of characters to match a single character in the set.

Syntax

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[…] — Where… is one or more single characters or character class escapes, excluding^ at the start and- between two entries in the set. Matches a character in the set. Example:[abc] matchesa,b, orc.
[^…] — Where… is one or more single characters or character class escapes, excluding- between two entries in the set. Matches any character not in the set. Example:[^abc] matchesd,e, orf, etc., but nota,b, orc.
[a-z] — Wherea andz are single characters or character escapes. Matches any character in the range betweena andz (inclusive). Example:[a-c] matchesa,b, orc, but notd.

Feature: Posix Character Classes

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APosix Character Class is a member of aCharacter Class set that specifies a named, pre-defined set of characters.

Syntax

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[[:name:]] — Wherename is in a set of predefined names. Matches any character in the set.

Feature: Negated Posix Character Classes

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ANegated Posix Character Class is a member of aCharacter Class set that specifies a named, pre-defined set of excluded characters.

Syntax

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[[:^name:]] — Wherename is in a set of predefined names. Matches any character not in the set.

Feature: Collating Elements

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Feature: Equivalence Classes

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Feature: Character Class Escapes

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ACharacter Class Escape is a single character escape that represents an entire character class. They can be used as an element of aCharacter Class or as anAtom. It is often the case that a lower-case escape character is the inclusive set, while an upper-case variant of the same character excludes that set.

Syntax

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\d — A digit character.
- Non-unicode mode: Equivalent to[0-9].
- Unicode mode: Equivalent to\p{General_Category=Decimal_Number}
\D — Any non-digit character.
- Non-unicode mode: Equivalent to[^0-9].
- Unicode mode: Equivalent to\P{General_Category=Decimal_Number}
\h — Any hexadecimal digit character. Equivalent to[0-9a-fA-F].
\H — Any non-hexadecimal character. Equivalent to[^0-9a-fA-F].
\w — Any “word” character.
- Non-unicode mode: Equivalent to[a-zA-Z0-9_].
- Unicode mode: Any character in the following General_Category sets: Letter, Mark, Number, Connector_Punctuation
\W — Any non-“word” character.
- Non-unicode mode: Equivalent to[^a-zA-Z0-9_].
- Unicode mode: Any character not in the following General_Category sets: Letter, Mark, Number, Connector_Punctuation
\s — Any whitespace character.
- Non-unicode mode: Any character in the set\t,\n,\v,\f,\r,\x20.
- Unicode mode: Any character in the setU+0009,U+000A,U+000B,U+000C,U+000D,U+0085, or the following General_Category sets: Line_Separator, Paragraph_Separator, Space_Separator
\S — Any non-whitespace character.
- Non-unicode mode: Any character not in the set\t,\n,\v,\f,\r,\x20.
- Unicode mode: Any character not in the setU+0009,U+000A,U+000B,U+000C,U+000D,U+0085, or the following General_Category sets: Line_Separator, Paragraph_Separator, Space_Separator
\N — Any non-newline character. Equivalent to(?-m:.).
- NOTE: Them-flag in Oniguruma is equivalent to thes-flag (i.e., dot all) in Perl, ECMAScript, .NET, etc.
\O — Any character. Equivalent to(?m:.).
- NOTE: Them-flag in Oniguruma is equivalent to thes-flag (i.e., dot all) in Perl, ECMAScript, .NET, etc.
\X — Text segment. Equivalent to(?>\O(?:\Y\O)*).

Feature: Line Endings Escape

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ALine Endings Escape is anAtom that matches any line ending character sequence.

Syntax

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\R — Equivalent to(?>\r\n?|[\x0A-\x0C\x85\u{2028}\u{2029}])

Feature: Character Property Escapes

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ACharacter Property Escape is an escape sequence used to match a character with a specific character property.

Syntax

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\p{name} — Wherename is a predefined property name. Matches a character that has the propertyname.
\p{^name} — Wherename is a predefined property name. Matches a character that does not have the propertyname.
\P{name} — Wherename is a predefined property name. Matches a character that does not have the propertyname.

Feature: Character Class Nested Set

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ACharacter Class Nested Set allows you to to define a nestedcharacter class inside of acharacter class.

Syntax

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[[…]] — Matches any character in the set, just like a normalcharacter class.
[[^…]] — Where… is one or more single characters or character class escapes, excluding- between two entries in the set. Matches any character not in the set, just like a normal [negated character class].
[[a-z]] — Wherea andz are single characters or character escapes. Matches any character in the range betweena andz (inclusive), just like a normal [character class range].

Example

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[a-z&&[^d-q]]

Is equivalent to:

[a-cr-z]

Feature: Character Class Intersection

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Character Class Intersection allows you to indicate that only characters that are in bothcharacter classes should match.

Syntax

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[…&&…] — Matches any character that is in both the left- and right-hand sets of&&.

Feature: Character Class Union

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Feature: Character Class Subtraction

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Character Class Subtraction allows you to exclude a class of characters from another class of characters in acharacter class.

Example

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[a-w&&[^c-g]z]

Is equivalent to the following pseudo pattern:

([a-w] AND ([^c-g] OR z))

Which reduces to:

[abh-w]

Source for this example comes from Oniguruma:source

Feature: Character Class Symmetric Difference

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Feature: Character Class Complement

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Feature: Quoted Characters

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Feature: Quantifiers

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Quantifiers specify repetition of anAtom. By default, quantifiers are “greedy” in that they attempt to match as many instances of the precedingAtom as possible to satisfy the pattern before backtracking.

Syntax

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* — Matches the precedingAtom zero or more times. Example:a*b matchesb,ab,aab,aaab, etc.
+ — Matches the precedingAtom one or more times. Example:a+b matchesab,aab,aaab, etc., but notb.
? — Matches the precedingAtom zero or one times. Example:a?b matchesb,ab.
{n} — Wheren is an integer. Matches the precedingAtom exactlyn times. Example:a{2} matchesaa but nota oraaa.
{n,} — Wheren is an integer. Matches the precedingAtom at-leastn times. Example:a{2,} matchesaa,aaa,aaaa, etc., but nota.
{n,m} — Wheren andm are integers, andm >=n. Matches the precedingAtom at-leastn times and at-mostm times. Example:a{2,3} matchesaa,aaa,aaaa, etc., but nota oraaaa.

Feature: Lazy Quantifiers

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Lazy Quantifiers specify repetition of anAtom, but attempt to match as few instances of the precedingAtom as possible to satisfy the pattern before advancing.

Syntax

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*? — Matches the precedingAtom zero or more times.
+? — Matches the precedingAtom one or more times.
?? — Matches the precedingAtom zero or one times.
{n}? — Wheren is an integer. Matches the precedingAtom exactlyn times.
{n,}? — Wheren is an integer. Matches the precedingAtom at-leastn times.
{n,m}? — Wheren andm are integers, andm >=n. Matches the precedingAtom at-leastn times and at-mostm times.

Feature: Possessive Quantifiers

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Possessive Quantifiers are like greedy (i.e., regular)quantifiers, except that backtracking is not performed.

Syntax

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*+ — Match zero or more characters without backtracking.
++ — Match one or more characters without backtracking.
?+ — Match zero or one characters without backtracking.
{n,}+ — Wheren is an integer. Matches the precedingAtom at-leastn times without backtracking.
{n,m}+ — Wheren andm are integers, andm >=n. Matches the precedingAtom at-leastn times and at-mostm times without backtracking.

Feature: Capturing Groups

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ACapturing Group is a subexpression that can be treated as anAtom and can be repeated usingQuantifiers and referenced usingBackreferences by index. A Capturing Group can be captured and returned by the matching algorithm.

Syntax

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(…) — Groups the subexpression as a singleAtom. The result is captured and returned by the matching algorithm.

Feature: Named Capturing Groups

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ANamed Capturing Group is a subexpression that can be captured and returned by the matching algorithm. A Named Capturing Group is also anAtom and can be repeated usingQuantifiers and referenced usingBackreferences by name.

Syntax

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(?<name>…) — Groups the subexpression as a singleAtom associated with the providedname. The result is captured and returned by the matching algorithm.
(?'name'…) — Groups the subexpression as a singleAtom associated with the providedname. The result is captured and returned by the matching algorithm.

Feature: Non-Capturing Groups

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ANon-capturing Group is a subexpression that can be treated as anAtom and can be repeated usingQuantifiers but cannot be referenced usingBackreferences. A Non-capturing Group is not captured by the matching algorithm.

Syntax

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(?:…) — Groups the subexpression as a singleAtom.

Feature: Backreferences

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Backreferences allow a pattern to re-match a previously matched capture group¹² either by number (n) or byname.

Syntax

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\n — Wheren is a decimal digit in the range 1-9. Matches the same string as thecapture groupn.
\k<n> — Wheren is an integer > 0. Matches the same string as thecapture groupn.
\k'n' — Wheren is an integer > 0. Matches the same string as thecapture groupn.
\k<-n> — Wheren is an integer > 0. Matches thenth previouscapture group.
\k'-n' — Wheren is an integer > 0. Matches thenth previouscapture group.
\k<+n> — Wheren is an integer > 0. Matches thenth nextcapture group.
\k'+n' — Wheren is an integer > 0. Matches thenth nextcapture group.
\k<name> — Matches the same string as thenamed capture group with the namename.
\k'name' — Matches the same string as thenamed capture group with the namename.

Feature: Comments

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AComment is a sequence of characters that is ignored by pattern matching and can be used to document a pattern.

Syntax

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(?#…) — The entire expression is removed from the pattern. A comment may not contain other( or) characters.

Feature: Line Comments

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Feature: Modifiers

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Modifiers allow you to change the currently activeRegExp flags within a subexpression.

Syntax

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(?imxWDSPy-imxWDSPy) - Sets or unsets (using-) the specifiedRegExp flags starting at the current position until the next closing) or the end of the pattern. Example:(?-i)A(?i)B(?-i)C matchesABC,AbC.
- NOTE: When optionONIG_SYNTAX_ONIGURUMA is specified, them-flag in Oniguruma is equivalent to thes-flag (i.e., dot all) in Perl, ECMAScript, .NET, etc.^reference
- NOTE: When optionONIG_SYNTAX_PERL orONIG_SYNTAX_JAVA are specified, them ands flags are equivalent to their Perl/Java counterparts.^reference
(?imxWDSPy-imxWDSPy:…) - Sets or unsets (using-) the specifiedRegExp flags for the subexpression. Example:(?-i:A(?i:B)C) matchesABC,AbC.
- NOTE: When optionONIG_SYNTAX_ONIGURUMA is specified, them-flag in Oniguruma is equivalent to thes-flag (i.e., dot all) in Perl, ECMAScript, .NET, etc.^reference
- NOTE: When optionONIG_SYNTAX_PERL orONIG_SYNTAX_JAVA are specified, them ands flags are equivalent to their Perl/Java counterparts.^reference

Feature: Branch Reset

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Feature: Lookahead

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ALookahead is a zero-width assertion that matches if the provided pattern would match the characters to the right of the current position.

Syntax

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(?=…) — Positive Lookahead. Matches if the provided pattern would match but does not advance the current position.
(?!…) — Negative Lookahead. Matches if the provided pattern would not match, but does not advance the current position.

Feature: Lookbehind

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ALookbehind is a zero-width assertion that matches if the provided pattern would match the characters to the left of the current position.

Syntax

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(?<=…) — Positive Lookbehind. Matches if the provided pattern would match the preceding characters, but does not advance the current position. The pattern must have a fixed length (unboundedquantifiers are not permitted).
(?<!…) — Negative Lookbehind. Matches if the provided pattern would not match the preceding characters, but does not advance the current position. The pattern must have a fixed length (unboundedquantifiers are not permitted).

Feature: Non-Backtracking Expressions

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ANon-Backtracking Expression is matched independent of neighboring patterns, and will not backtrack in the event of a failed match. This is often used to improve performance.

Syntax

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(?>…) — Matches the provided pattern, but no backtracking is performed if the match fails.

Feature: Recursion

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ARecursive Expression provides a mechanism for re-evaluating acapture group inside of itself, to handle cases such as matching balanced parenthesis or brackets, etc.

Syntax

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\k<n+n> — Wheren is an integer >= 1 andlevel is an integer >= 0. Matches the same string as thecapture groupn at the recursion level relative to the referencedcapture group.
\k'n+n' — Wheren is an integer >= 1 andlevel is an integer >= 0. Matches the same string as thecapture groupn at the recursion level relative to the referencedcapture group.
\k<n-n> — Wheren is an integer >= 1 andlevel is an integer >= 0. Matches the same string as thecapture groupn at the recursion level relative to the referencedcapture group.
\k'n-n' — Wheren is an integer >= 1 andlevel is an integer >= 0. Matches the same string as thecapture groupn at the recursion level relative to the referencedcapture group.
\k<name> — Wherelevel is an integer >= 0. Matches the same string as thenamed capture group with the namename at the recursion level relative to the referencednamed capture group.
\k'name' — Wherelevel is an integer >= 0. Matches the same string as thenamed capture group with the namename at the recursion level relative to the referencednamed capture group.
\g<n> — Wheren is an integer >= 1. Evaluates thecapture group whose offset isn.
\g'n' — Wheren is an integer >= 1. Evaluates thecapture group whose offset isn.
\g<0> — Evaluates the entire pattern at the current position.
\g'0' — Evaluates the entire pattern at the current position.
\g<-n> — Wheren is an integer >= 1. Evaluates thecapture group whose offset is thenthcapture group declared to the left of the currentAtom.
\g'-n' — Wheren is an integer >= 1. Evaluates thecapture group whose offset is thenthcapture group declared to the left of the currentAtom.
\g<+n> — Wheren is an integer >= 1. Evaluates thecapture group whose offset is thenthcapture group declared to the right of the currentAtom.
\g'+n' — Wheren is an integer >= 1. Evaluates thecapture group whose offset is thenthcapture group declared to the right of the currentAtom.
\g<name> — Evaluates thenamed capture group with the providedname.
\g'name' — Evaluates thenamed capture group with the providedname.

Feature: Conditional Expressions

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AConditional Expression checks a condition and evaluates its first alternative if the condition istrue; otherwise, it evaluates its second alternative.

Syntax

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(?(condition)condition|condition) — Matchesyes-pattern ifcondition istrue; otherwise, matchesno-pattern.
(?(condition)condition) — Matchesyes-pattern ifcondition istrue; otherwise, matches the empty string.

Conditions

The following conditions are supported:

(?(?=test-pattern)…) — Evaluates totrue if alookahead fortest-pattern matches; otherwise, evaluates tofalse.
(?(?!test-pattern)…) — Evaluates totrue if a negativelookahead fortest-pattern matches; otherwise, evaluates tofalse.
(?(n)…) — Evaluates totrue if thecapture group at offsetn was successfully matched; otherwise, evaluates tofalse.
(?(-n)…) — Evaluates totrue if thenthcapture group declared to the left of the currentAtom was successfully matched; otherwise, evaluates tofalse.
(?(+n)…) — Evaluates totrue if thenthcapture group declared to the right of the currentAtom was successfully matched; otherwise, evaluates tofalse.
(?(n-n)…) — Evaluates totrue if thecapture group at offsetn was successfully matched at the recursion level relative to the referencedcapture group; otherwise, evaluates tofalse.
(?(n+n)…) — Evaluates totrue if thecapture group at offsetn was successfully matched at the recursion level relative to the referencedcapture group; otherwise, evaluates tofalse.
(?(<name>)…) — Evaluates totrue if thenamed capture group with the namename was successfully matched; otherwise, evaluates tofalse.
(?('name')…) — Evaluates totrue if thenamed capture group with the namename was successfully matched; otherwise, evaluates tofalse.
(?(<name-name>)…) — Evaluates totrue if thenamed capture group with the namename was successfully matched at the recursion level relative to the referencedcapture group; otherwise, evaluates tofalse.
(?('name-name')…) — Evaluates totrue if thenamed capture group with the namename was successfully matched at the recursion level relative to the referencedcapture group; otherwise, evaluates tofalse.
(?(<name+name>)…) — Evaluates totrue if thenamed capture group with the namename was successfully matched at the recursion level relative to the referencedcapture group; otherwise, evaluates tofalse.
(?('name+name')…) — Evaluates totrue if thenamed capture group with the namename was successfully matched at the recursion level relative to the referencedcapture group; otherwise, evaluates tofalse.

Feature: Subroutines

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ASubroutine is a pre-definedcapture group ornamed capture group that can be reused in multiple places within the pattern to re-evaluate the subexpression from the group.

Syntax

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\g<n> — Wheren is an integer >= 1. Evaluates thecapture group whose offset isn.
\g'n' — Wheren is an integer >= 1. Evaluates thecapture group whose offset isn.
\g<0> — Evaluates the entire pattern at the current position.
\g'0' — Evaluates the entire pattern at the current position.
\g<-n> — Wheren is an integer >= 1. Evaluates thecapture group whose offset is thenthcapture group declared to the left of the currentAtom.
\g'-n' — Wheren is an integer >= 1. Evaluates thecapture group whose offset is thenthcapture group declared to the left of the currentAtom.
\g<+n> — Wheren is an integer >= 1. Evaluates thecapture group whose offset is thenthcapture group declared to the right of the currentAtom.
\g'+n' — Wheren is an integer >= 1. Evaluates thecapture group whose offset is thenthcapture group declared to the right of the currentAtom.
\g<name> — Evaluates thenamed capture group with the providedname.
\g'name' — Evaluates thenamed capture group with the providedname.

Example

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(?(DEFINE)  (?<Year>\d{4}|[+-]\d{5,})  (?<Month>0[1-9]|1[0-2])  (?<Day>0[1-9]|2[0-9]|3[01]))(?<Date>(?&Year)-(?&Month)-(?&Day)|(?&Year)(?&Month)(?&Day))

Feature: Callouts

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ACallout is a user-defined function that can be evaluated while matching.

Syntax

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Callouts of contents:
- (?{…contents…}) — Invokes the callout with the providedcontents.
- (?{…contents…}D) — Invokes the callout with the providedcontents and direction flag characterD. The direction flag must be one of:
  - X — Invoked while progressing and retracting.
  - < — Invoked while retracting.
  - > — Invoked while progressing.
- (?{…contents…}[tag]) — Invokes the callout with the providedcontents andtag.
- (?{…contents…}[tag]D) — Invokes the callout with the providedcontents,tag, and direction flag characterD. The direction flag must be one of:
  - X — Invoked while progressing and retracting.
  - < — Invoked while retracting.
  - > — Invoked while progressing.
Callouts ofname:
(*name) — Invokes the callout with the providedname.
(*name{args…}) — Invokes the callout with the providedname andargs.
(*name[tag]) — Invokes the callout with the providedname andtag.
(*name[tag]{args…}) — Invokes the callout with the providedname,tag, andargs.

Feature: Backtracking Control Verbs

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Movatterモバイル変換

Engine: Oniguruma

Languages

Features

Feature: Flags

Syntax

See Also

Feature: Anchors

Syntax

See Also

Feature: Buffer Boundaries

Syntax

See Also

Feature: Word Boundaries

Syntax

See Also

Feature: Text Segment Boundaries

Syntax

See Also

Feature: Continuation Escape

Syntax

See Also

Feature: Alternatives

Syntax

Feature: Wildcard

Syntax

Feature: Character Classes

Syntax

See Also

Feature: Posix Character Classes

Syntax

See Also

Feature: Negated Posix Character Classes

Syntax

See Also

Feature: Collating Elements

See Also

Feature: Equivalence Classes

See Also

Feature: Character Class Escapes

Syntax

See Also

Feature: Line Endings Escape

Syntax

See Also

Feature: Character Property Escapes

Syntax

See Also

Feature: Character Class Nested Set

Syntax

Example

See Also

Feature: Character Class Intersection

Syntax

See Also

Feature: Character Class Union

See Also

Feature: Character Class Subtraction

Example

See Also

Feature: Character Class Symmetric Difference

See Also

Feature: Character Class Complement

See Also

Feature: Quoted Characters

Feature: Quantifiers

Syntax

See Also

Feature: Lazy Quantifiers

Syntax

See Also

Feature: Possessive Quantifiers

Syntax

See Also

Feature: Capturing Groups

Syntax

See Also

Feature: Named Capturing Groups

Syntax

See Also