\[the literal [ (9110 / 1338 / 5B16)
ifthe literal text if (case sensitive) \s+any whitespace character, repeated at least once
Negated Character Class[^\]]*+ *+matches any number of characters outside the set below:
\]the literal ] (9310 / 1358 / 5D16)
\]the literal ] (9310 / 1358 / 5D16)
Group 3((?>[^[]++(?:\[(?!(?:end)?if\b)[^[]*)*|(?R))*) Atomic Group(?>[^[]++(?:\[(?!(?:end)?if\b)[^[]*)*|(?R))* *repeats the group contents below any number of times:
1st Alternative[^[]++(?:\[(?!(?:end)?if\b)[^[]*)* Negated Character Class[^[]++ ++matches at least one character outside the set below:
[the literal [ (9110 / 1338 / 5B16)
Non-Capturing Group(?:\[(?!(?:end)?if\b)[^[]*)* *repeats the group contents below any number of times:
\[the literal [ (9110 / 1338 / 5B16)
Negative Lookahead(?!(?:end)?if\b) Non-Capturing Group(?:end)? ?repeats the group contents below at most once:
endthe literal text end (case sensitive) ifthe literal text if (case sensitive) \ban ASCII word boundary
Negated Character Class[^[]* *matches any number of characters outside the set below:
[the literal [ (9110 / 1338 / 5B16)
(?R)recurses into the entire pattern
\[the literal [ (9110 / 1338 / 5B16)
endifthe literal text endif (case sensitive) \]the literal ] (9310 / 1358 / 5D16)
s modifier: single line. Allows a dot to match line terminators
x modifier: extended. Ignores unescaped whitespace and comments outside character classes