Escaping a `]` inside a posix class `[[:\]:]` does funky stuff

RedCMD commented 2 years ago

The regex [[:upper:]] works as expected at matching only upper case letters. Normally if you missspell anything inside the posix class, the textmate engine will fail. Except for a few noteble expcetions; ], : and [: (only gonna focus on ] for now) [[:upp]er:]] will work with matching :], u], p], e] and r]. (regex: [:uper]\]). But if you escape the ] inside the posix class, then both square brackets acts as both the closing and opening brackets for the 2nd character class and as literary characters for the 1st class. Leaving the last ] competely out of the classes (and can be removed without error). [[:upp\]er:]] will match the same as above but also with the added [ and ]. :], u], p], e] r] [] and ]]. (regex:[\[:uper\]]\]). [[:\]:] will match [, : and ]. ~Placing a - before the last : causes textmate engine to fail [[:\]-:].~ (EDIT: \]-: is an illegal character range) Regex works as expected if either : is removed or moved one space away from their respected square bracket. (I have used a single \ instead of the required double \\ from json embeding)

RedCMD commented 2 years ago

Posix classes are some of the funkiest things in textmate. The below regex is allowed and will match all upper case letters aswell as a, b and c. But if posix a value is inputted, the engine breaks: