Regular Expressions 101

Pro

\ban ASCII word boundary

Non-Capturing Group(?:if|for)

1st Alternativeif

ifthe literal text if (case sensitive)

2nd Alternativefor

forthe literal text for (case sensitive)

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

Group 1($([^()]++|(?1))*$)

\(the literal ( (40₁₀ / 50₈ / 28₁₆)

Group 2([^()]++|(?1))*

*repeats the group contents below any number of times:

1st Alternative[^()]++

Negated Character Class[^()]++

++matches at least one character outside the set below:

(the literal ( (40₁₀ / 50₈ / 28₁₆)

)the literal ) (41₁₀ / 51₈ / 29₁₆)

2nd Alternative(?1)

(?1)calls group 1 as a subroutine

\)the literal ) (41₁₀ / 51₈ / 29₁₆)

Negative Lookahead(?!.*{|.*\n.*{)

1st Alternative.*{

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

{the literal { (123₁₀ / 173₈ / 7B₁₆)

2nd Alternative.*\n.*{

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

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

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

{the literal { (123₁₀ / 173₈ / 7B₁₆)

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

Ready to run

25 tokens

\b(?:if|for)\s*(\(([^()]++|(?1))*\))(?!.*{|.*\n.*{)