Ask HN: Python library for regex with “extent-of-match”

[georgeam]

From CS Theory, all regular expressions can be converted to deterministic finite automata. I would like a python library that tells me the precise point at which a string "loses hope" of matching a regular expression. Eg.

Given a regular expression like aba*

And a string like abbab

I want an output that says the match failed at an index of 2.

meaning that the first ab match (or more technically, are the prefix of a match), but the remaining bab "kill" the possibility of a match.

Anyone know of a python library that does this?