A Swift regular expression library supporting:
- Generically typed symbols – Not only
Strings ofCharacter, but all Swift types in anySequence. - Predicate based symbol matching – Define match conditions on symbols such as
.require { $0.speed < 30 },.require { $0.color.isFairlyRed }, orrequire { $0.networkEvent.completedWithoutError }. - Linear run time and constant memory use in the input sequence length.
Regular doesn't currently support expression negation, but it is an ambition to add this.
Regular is intended as a way to specify and validate event sequence expectations in tests, and to investigate whether this is a sensible thing to do in test specifications.
It might be useful for something else though. Such as matching event sequences from a Combine publisher.
Regular is not a RegEx library for string based regular expressions. It does not attempt to support the syntax of RegEx. Lots of libraries do this already and Swift already has support. Regular's intent is to let you use the same concepts to process sequences of anything.
Regular is unlkely to be fast and I've not made any optimisation effort yet. However, the underlying algorithm is linear time time and contant space, and various optimisations could be made without a change of API.
Regular is currently work in progress. However, Regular has an NFA based matching implementation, and an API for creating expressions and building matchers from them.
- Check it's actually useful for building expressions and matchers.
- Ensure naming in expression algebra isn't overly verbose.
- Support negation.