regex AND operator with negative arguments

Question

I'm trying to match lines that doesn't end with either . or ! and doesn't end with either ." or !" so it should match both

• say "bye"
• say "bye

but shouldn't match:

• say "bye.
• say "bye!
• say "bye."
• say "bye!"

I tried using positive and negative lookahead, trying to use them as AND as suggested in Regex AND operator, but I can't make it work, nor I'm sure it's feasible with lookaheads.

Answer 1

Just use a negative lookbehind. This matches exactly what you asked for: ^.*+(?<![.!]"?)$

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^ - beginning of line
.*+ - any amount of characters, not giving up for backtracking
(?<! + ) - not preceded by
[.!] - dot or exclamation mark
"? - optional double-quote
$ - end of line

Answer 2

Ensure bye isn't succeeded by . or ! with a positive look-ahead for a negative character class, and then make the last " optional with the ? quantifier:

\bsay "bye(?=[^.!])"?

Answer 3

You can use

^(?!.*[.!]"?$).*$

Regex Demo

Note:- This matches empty line too as we use * which means match anything zero or more time, if you want to avoid empty lines to match you can use + quantifier which means match one or more time