You want the parser generator library to automagically produce an AST and fill it in from the grammar description? Tree Sitter (I think) does that but (I belie

You want the parser generator library to automagically produce an AST and fill it in from the grammar description? Tree Sitter (I think) does that but (I believe) its output is a parse tree. For the N:M stuff, if I understand you correctly, sounds like global value numbering could do that as, if I understand it correctly, it gives you subexpression deduplication for free. I think this is a tree transformation step though — haven’t really thought about it before but it could probably be implemented as the parser output but would be destructive as you’d lose line number information and whatnot. Personally, for my playing around, I use asdl to generate the AST nodes because its a super-simple ‘language’ so I can easily test out new things. I’ve reimplemented it probably five or six times now but that definitely qualifies as yak shaving.