regex101: PCRE (Legacy) Match Workspace

1st Alternative\A(?:(?=(?(3)[\s\S]*(?=\3\z))(?|.(?=.*\n(\1?+.).*\n(\2?+.))|.*\n()())+?(?<=X)(?=.*\n\1(?<=X).*\n\2(?<=X))(?=([\s\S]*\z)))(?=[\s\S]*([\s\S](?(4)\4)))[\s\S])+[\s\S]*(?=\4\z)

\Astart of string

Non-Capturing Group(?:(?=(?(3)[\s\S]*(?=\3\z))(?|.(?=.*\n(\1?+.).*\n(\2?+.))|.*\n()())+?(?<=X)(?=.*\n\1(?<=X).*\n\2(?<=X))(?=([\s\S]*\z)))(?=[\s\S]*([\s\S](?(4)\4)))[\s\S])+

+repeats the group contents below at least once:

Positive Lookahead(?=(?(3)[\s\S]*(?=\3\z))(?|.(?=.*\n(\1?+.).*\n(\2?+.))|.*\n()())+?(?<=X)(?=.*\n\1(?<=X).*\n\2(?<=X))(?=([\s\S]*\z)))

Condition(?(3)[\s\S]*(?=\3\z))

Uses the first branch if group 3 matched

If the condition is true, match this branch:[\s\S]*(?=\3\z)

Character Class[\s\S]*

*matches any number of characters from the set below:

\sany whitespace character

\Sany non-whitespace character

Positive Lookahead(?=\3\z)

\3the text saved by group 3

\zend of string

Branch Reset Group(?|.(?=.*\n(\1?+.).*\n(\2?+.))|.*\n()())+?

+?repeats the group contents below at least once:

1st Alternative.(?=.*\n(\1?+.).*\n(\2?+.))

.any character (except for line terminators)

Positive Lookahead(?=.*\n(\1?+.).*\n(\2?+.))

.*any character (except for line terminators), repeated any number of times

\na line-feed (newline) character (ASCII 10)

Group 1(\1?+.)

\1?+optionally matches the text saved by group 1

.any character (except for line terminators)

.*any character (except for line terminators), repeated any number of times

\na line-feed (newline) character (ASCII 10)

Group 2(\2?+.)

\2?+optionally matches the text saved by group 2

.any character (except for line terminators)

2nd Alternative.*\n()()

.*any character (except for line terminators), repeated any number of times

\na line-feed (newline) character (ASCII 10)

Group 1() — always finds a zero-length match

Group 2() — always finds a zero-length match

Positive Lookbehind(?<=X)

Xthe literal X (88₁₀ / 130₈ / 58₁₆) (case sensitive)

Positive Lookahead(?=.*\n\1(?<=X).*\n\2(?<=X))

.*any character (except for line terminators), repeated any number of times

\na line-feed (newline) character (ASCII 10)

\1the text saved by group 1

Positive Lookbehind(?<=X)

Xthe literal X (88₁₀ / 130₈ / 58₁₆) (case sensitive)

.*any character (except for line terminators), repeated any number of times

\na line-feed (newline) character (ASCII 10)

\2the text saved by group 2

Positive Lookbehind(?<=X)

Xthe literal X (88₁₀ / 130₈ / 58₁₆) (case sensitive)

Positive Lookahead(?=([\s\S]*\z))

Group 3([\s\S]*\z)

Character Class[\s\S]*

*matches any number of characters from the set below:

\sany whitespace character

\Sany non-whitespace character

\zend of string

Positive Lookahead(?=[\s\S]*([\s\S](?(4)\4)))

Character Class[\s\S]*

*matches any number of characters from the set below:

\sany whitespace character

\Sany non-whitespace character

Group 4([\s\S](?(4)\4))

Character Class[\s\S]

\sany whitespace character

\Sany non-whitespace character

Condition(?(4)\4)

Uses the first branch if group 4 matched

If the condition is true, match this branch:\4

Character Class[\s\S]

Character Class[\s\S]*

Positive Lookahead(?=\4\z)

2nd Alternative\G(?!\A|[\s\S]?\z)

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Search reference

Regular Expression

\A(?:(?=(?(3)[\s\S]*(?=\3\z))(?|.(?=.*\n(\1?+.).*\n(\2?+.))|.*\n()())+?(?<=X)(?=.*\n\1(?<=X).*\n\2(?<=X))(?=([\s\S]*\z)))(?=[\s\S]*([\s\S](?(4)\4)))[\s\S])+[\s\S]*(?=\4\z)|\G(?!\A|[\s\S]?\z)

Unit Tests

There are no unit tests, click to add some.