Feature: Character Class Nested Set

^{Home | Features | Improve this section}

A Character Class Nested Set allows you to to define a nested character class inside of a character class.

Syntax

^{Improve this section}

NOTE: The following syntax is an example based on some of the supported engines. For specific engine support, see Engines.

• [[…]] — Matches any character in the set, just like a normal character 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]] — Where a and z are single characters or character escapes. Matches any character in the range between a and z (inclusive), just like a normal [character class range].

Example

^{Improve this section}

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

Is equivalent to:

[a-cr-z]

Engines

Engine	Supported
Perl	✔
PCRE	❌
Boost.Regex	❌
.NET	❌
Oniguruma	✔
Hyperscan	❌
ICU	✔
Glib/GRegex	❌
ECMAScript	❌

See Also

^{Improve this section}

• Character Classes
• Posix Character Classes
• Negated Posix Character Classes
• Collating Elements
• Equivalence Classes
• Character Class Escapes
• Line Endings Escape
• Character Property Escapes
• Character Class Intersection
• Character Class Union
• Character Class Subtraction
• Character Class Symmetric Difference
• Character Class Complement