They're native in Perl 6, and people above have linked to libraries for Lua and Clojure. I think there's a library for Python as well somewhere or other. Also

They're native in Perl 6, and people above have linked to libraries for Lua and Clojure. I think there's a library for Python as well somewhere or other. Also peg/leg for C is intended (iirc) as a direct competitor to flex/bison et al.