This BABLR grammar defines a subset of regex that is safe to use in a nonbacktracking regex engine, in particular @bablr/regex-vm.
The language is the same as Javascript Regex except for these deifferences:
-
Expressions always use "unicode mode" escaping rules. Only valid escapes are syntactically legal.
-
Expressions do not support lookbehind (
/(?<=abc)/and/(?<!abc)/). -
Expressions do not (and will not) support backreferences (
/(.)\0/). -
Expressions do not support lookahead (yet) (
/(?=abc)/and/(?!abc)/). See #11. -
Expressions do not support named capture groups (
/(?<name>)/) (yet).