I noticed that once and I even implemented a library which type checks Python with custom "type systems" written in Prolog, it was shocking how flexible is that

I noticed that once and I even implemented a library which type checks Python with custom "type systems" written in Prolog, it was shocking how flexible is that, a bit like declarative grammars/parsing https://github.com/alehander42/hatlog https://github.com/alehander42/hatlog