regex::RegexSet-style Yes/No Matching on Alternatives

[maximaximal]

Another interesting and very useful feature that might not even be much work could be something similar to RegexSet. This would abstract over a big alternation of matches and provide the indices of matching patterns.

(sorry for "dumping" feature ideas, I wanted to post the issue before I start with a PR)

[ieviev]

Yes i definitely agree this would be very useful.
More generally i want to figure out how to do transducers and tagged lazy DFAs for RE# incrementally so it works with all the other features.. this would let us support capture groups as well.
But even a halfway step there is immediately applicable for eg cybersecurity tools.

[ieviev]

RegexSet now exists with a few extras,
it's behind the regex_set feature of v0.7.5

The API is still subject to change, but the idea is i'd like to have these 3 operations on it.

• matches -> returns indices of all patterns that matched, standard RegexSet operation. instead of running N regexes, you can run just one
• categorize_all / classify_all -> think multiclass classification. returns a single label per match. should also include a non-overlap constraint, such that every label is unique and matches at most one string (eg 1 to 1 enum mapping).
• label_all -> think multilabel classification, every match carries a set of all labels that apply to that span

possibly including overlapping variants for categorize/label as well if there's a good scenario to use them.

I wrote a bit about it here: https://iev.ee/blog/categorize-everything-all-at-once/

Let me know what you think