I’ve been adding transform/refactoring operations to Antlrvsix for the last two weeks. So far, I have the following: (1) replace parser string literals; (2) remove useless parser rules; (3) move parser start rules to top; (4) reorder parser rules alphabetically; (5) reorder parser rules vis BFS; (6) reorder parser rules DFS; (7) split combined grammars; (8) merge split grammars. I’ll soon start the really important transforms (rewrite rules to remove excessive factoring, left recursion, etc). I will also add in a Flex/Bison import tool to convert these grammars to Antlr. I’m making a release of Antlrvsix v5.5 with these changes, but much more is coming.