I think the warning should be parsing complex domains with regex libraries, not a restriction to regular syntaxes. There are simple cases where backtracking (or

I think the warning should be parsing complex domains with regex libraries, not a restriction to regular syntaxes. There are simple cases where backtracking (or some other extension) plus regex makes sense. Something like (\w+) \d+ \1 is simpler as a regex than any other common tool available.