I used TatSu back when it was named Grako, I really loved it.

But now, I discovered LALRPOP[0] and Logos[1] in Rust which is just so much more powerful, I'm using PyO3 to bring it to Python because I find it easier to walk the AST and do code generation from here.

[0] - http://lalrpop.github.io/lalrpop/

[1] - https://docs.rs/logos/latest/logos/