regex101: PCRE (Legacy) Match Workspace

Group function(?<function>\w+)

\w+any word character, repeated at least once

\(the literal ( (40₁₀ / 50₈ / 28₁₆)

Comment: Matches function name

Group parameters(?<parameters> # Simple param type. (?<data> # Simple data type: inner function or word (keep this order!). (?R) | # Or recursive this Regexp to match inner functions. \w+ # Matches a simple word. ) ( # Match additional parameters: \s*,\s* # Match comma, but skip spaces. \g<parameters> # Recurse additional parameters. )* # Zero or more additional parameters. )?

?repeats the group contents below at most once:

Comment: Simple param type.

Group data(?<data> # Simple data type: inner function or word (keep this order!). (?R) | # Or recursive this Regexp to match inner functions. \w+ # Matches a simple word. )

1st Alternative # Simple data type: inner function or word (keep this order!). (?R)

Comment: Simple data type: inner function or word (keep this order!).

(?R)recurses into the entire pattern

2nd Alternative # Or recursive this Regexp to match inner functions. \w+ # Matches a simple word.

Comment: Or recursive this Regexp to match inner functions.

\w+any word character, repeated at least once

Comment: Matches a simple word.

Group 4( # Match additional parameters: \s*,\s* # Match comma, but skip spaces. \g<parameters> # Recurse additional parameters. )*

*repeats the group contents below any number of times:

Comment: Match additional parameters:

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

,the literal , (44₁₀ / 54₈ / 2C₁₆)

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

Comment: Match comma, but skip spaces.

\g<parameters>calls group parameters as a subroutine

Comment: Recurse additional parameters.

Comment: Zero or more additional parameters.

Comment: Parameters are optional

\)the literal ) (41₁₀ / 51₈ / 29₁₆)

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

x modifier: extended. Ignores unescaped whitespace and comments outside character classes

Search reference

Regular Expression

(?<function>\w+) \(            # Matches function name
    (?<parameters>             # Simple param type.
        (?<data>               # Simple data type: inner function or word (keep this order!).
           (?R) |              # Or recursive this Regexp to match inner functions.
           \w+                 # Matches a simple word.
        )

        (                      # Match additional parameters:
            \s*,\s*            # Match comma, but skip spaces.
            \g<parameters>     # Recurse additional parameters.
        )*                     # Zero or more additional parameters.
    )?                         # Parameters are optional
\)

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