Look at new regex operators from TR18 about opentype-shaping-documents HOT 3 CLOSED

Interesting, that's a lot of set theoretic machinery to define this from scratch given that most regular expressions already allow [^a], although that's specifically a negated character class that can be interpreted as a shorthand for "the alternation of every possible character excluding 'a'" rather than a true complement operator that applies to arbitrary regexps.

from opentype-shaping-documents.

Yeah, sometimes with these Unicode documents I feel like I'm lacking some context that makes them all make clearer sense. E.g., they may be thinking about some particular RE language or system that this is a real improvement for.

from opentype-shaping-documents.

Having perused this a bit more, I don't see anything I think would affect shaping-level concerns. Possibly more useful for higher-level text handling.

from opentype-shaping-documents.