Re: Match something that does not match

It seems to me like the feature you're implementing could be described as "stop matching at" (Update: or "match until") rather than do_not_match. Your current regex in do_not_match can be simplified to qr{ (?: (?!$pat) . )* }x; at least that still passes all your test cases. (This regex is pretty simple; I'm not sure if it warrants inclusion in Regexp::Common.)

Update: WebPerl Regex Tester

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Re^2: Match something that does not match by jo37 (Curate) on Feb 15, 2020 at 20:42 UTC
Your regex is indeed the one I was after. Though it works, I still don't get it :-( And I agree with you: this is too simple for Regexp::Common Thanks for your comment. Still learning... -jo	[reply]
Re^3: Match something that does not match by haukex (Archbishop) on Feb 15, 2020 at 21:41 UTC
Though it works, I still don't get it :-( The `.` matches anything (except newline), and `(?!$pat)` means "the next thing can't be `$pat`", so taken all together it really just means "match any number of characters, where none of these characters may be the first character of `$pat`".	[reply] [d/l] [select]
Re^4: Match something that does not match by jo37 (Curate) on Feb 15, 2020 at 22:18 UTC
I was challenged by the mental step of putting something after a look-ahead assertion. Failing to understand this lead to the missing last character in the second branch of my original regex. Anyway, the fog lifts. Thanks a lot! -jo	[reply]