Is it possible to exclude parts of regular expression matches? Take this scenario as an example:
FREE SOFT FOUNDATION V2 1989 PAGE 2
STALLMANWORKS 2000 1977;PAGE 2
THE GNU PAGE 3 1977
I'm trying to match just FREE SOFT FOUNDATION, STALLMANWORKS 2000 and THE GNU. That's easy, but now I have to exclude any combination of [0-9;]+\s?(PAGE) that comes after the title. I tried a negative lookahead, but had no luck:
(?!([0-9]+\s?(PAGE)))([A-Z0-9\s]+)
I'm not so sure what might be desired here, my guess is that maybe this expression
([\s\S].*?)\b((?:\s*\d+\s+;?|\s*\d+;)PAGE\s+\d+|\s*PAGE.*[0-9])
may be OK to look into. Here, we would see what we would like to exclude then we would simply add:
([\s\S].*?)
to collect our desired chars.
You need to pair the negative lookahead with every character you match. Your example regexp does the negative lookahead check just at the first character.
Something like:
((?:(?!\s+V?[0-9]|\s+PAGE)[A-Z0-9\s])+)
If you only want to get those matches, you might use an anchor ^ to assert the start of the string;
In your example data it seems you don't want digits before page.
Perhaps you could use a tempered greedy token approach to assert what is on the right is not PAGE and then match any of the character class [A-Z0-9\s].
Then make sure that the match end with an uppercase A-Z followed by a word boundary \b an can optionally match 4 digits after ending on an uppercase A-Z.
^(?:(?! PAGE)[A-Z0-9\s])+[A-Z](?: \d{4})?\b
Explanation
^ Start of string(?: Non capturing group
(?! PAGE) Negative lookahead, assert what is directly on the right is not[A-Z0-9\s] Match any of the listed in the character class)+ Close non capturing group and repeat 1+ times[A-Z] Match uppercase A-Z followed by a word boundary(?: \d{4})? Optionally match a space and 4 digits\b Word boundary