SE-0354 (Second Review): Regex Literals

[hamishknight]

@michelf

@hamishknight

I'm not sure whether we'd want the warning to apply to a character class such as [ a b c ] though (maybe only if there's a single space?).

You can write a significant space with [ ] in Perl, so I assume it'd work similarly here. Whitespace is not ignored in a character class.

In SE-0355: Regex Syntax and Runtime Construction, we are proposing a unified non-semantic whitespace behavior that treats whitespace as non-semantic both inside and outside custom character classes:

In both PCRE and Perl, this is enabled through the (?x) , and in later versions, (?xx) matching options. The former allows non-semantic whitespace outside of character classes, and the latter also allows non-semantic whitespace in custom character classes.

Oniguruma, Java, and ICU however enable the more broad behavior under (?x) . We therefore propose following this behavior, with (?x) and (?xx) being treated the same.