I was searching my package manager for parser generators, and I came across this old piece of code generator called ‘CLIPS’ that was created by NASA back in the 80s to generate expert systems in C. It is still under active development, the manual in /usr/share/doc/clips-doc is from 2015. It uses a LISP-like language to specify an expert system. It’s a very interesting piece of software and I am surprised that people still have use for it. This branch of ML seems abandoned for the most part. But I guess a lot of game developers could make use of CLIPS. Give it a look.