This strikes me as cool to see someone build another language with python using lark, it's also possible to override the ">>" or "|" characters in python to achieve the same thing, and also you don't have to worry about the "lark" grammar.

I had a custom lark grammar I thought was cool to do something similar, but after a while I just discarded it and went back to straight python, and found it was faster my an order of magnitude.