Rex is a straight-forward regular expression engine based on state machines, with the secondary goal of having similar complexity characteristics as RE2 (of course without being so fast, as that entails a lot more work). On various pathological REs this goal has already been achieved.
The primary goal however is to have a navigable documented code base for a regular expression engine. For this purpose, there is an all-members-documented documentation available at borgac.net/~lbo/doc/rex_regex/rex_regex/.
Benchmarks can be run with cargo bench.
- Submatches can not start at the same position.