I helped out with parser as well for a while, though it was mostly documentation, triaging issues, that sort of thing. I think I still have push access to the Gem, as at the time the project had a bus factor of 1 (= whitequark).

Anyway, I remember just how frustrated whitequark would get every time CRuby decided to make some random syntax change. I have a lot of respect for the current maintainer(s) for putting up with the ever growing complexity of the Ruby syntax. I hope Ruby stops changing the syntax on a regular basis, but I doubt this will happen any time soon.