Rewrite the Groovy grammar to Antlr 3 Groovy's grammar is based on Antlr 2.7, but the project is to move to a newer version of Antlr. However, the migration is not seemless and transparent, so it would be a great opportunity to do a better clean room re-implementation of the Groovy grammar. A new grammar would be cleaner, easier to work with, especially as various IDE tools help author Antlr 3 grammars better than the previous versions.