For anyone interested, I've sketched up a grammar for parsing WKT geometries. (http://en.wikipedia.org/wiki/Well-known_text) It's available at http://gist.github.com/1048372 It's based very closely on the OGC specification, but is basically untested at this stage. This is my first stab at using Jison (or any parser generator for that matter) - any constructive comments will be appreciated. -James