Regular Expressions 101

Pro

Group 1(\w+)

\w+any word character, repeated at least once

Non-Capturing Group(?:\s*=\s*((\{\{((?>(?!\{\{|}})(?s).|(?3))*)}})|\w+))?

?repeats the group contents below at most once:

\s*any whitespace character, repeated any number of times

=the literal = (61₁₀ / 75₈ / 3D₁₆)

\s*any whitespace character, repeated any number of times

Group 2((\{\{((?>(?!\{\{|}})(?s).|(?3))*)}})|\w+)

1st Alternative(\{\{((?>(?!\{\{|}})(?s).|(?3))*)}})

Group 3(\{\{((?>(?!\{\{|}})(?s).|(?3))*)}})

\{the literal { (123₁₀ / 173₈ / 7B₁₆)

Group 4((?>(?!\{\{|}})(?s).|(?3))*)

Atomic Group(?>(?!\{\{|}})(?s).|(?3))*

*repeats the group contents below any number of times:

1st Alternative(?!\{\{|}})(?s).

Negative Lookahead(?!\{\{|}})

1st Alternative\{\{

\{the literal { (123₁₀ / 173₈ / 7B₁₆)

2nd Alternative}}

}}the literal text }}

(?s)applies the following effective flags to the remainder of the pattern: gms

s modifier: single line. Allows a dot to match line terminators

.any character

2nd Alternative(?3)

(?3)calls group 3 as a subroutine

}}the literal text }}

2nd Alternative\w+

\w+any word character, repeated at least once

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

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25 tokens

(\w+)(?:\s*=\s*((\{\{((?>(?!\{\{|}})(?s).|(?3))*)}})|\w+))?

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