That's the largest piece of Prolog code I've ever written, so criticism is warranted and I'm glad to learn how to improve it. I still wanted to share it to show

That's the largest piece of Prolog code I've ever written, so criticism is warranted and I'm glad to learn how to improve it. I still wanted to share it to show how typing rules translated almost directly to Prolog clauses. I agree that this piece of code was written in a more academic mindset, with large dose of TAPL-specific jargon and abbreviations which can easily throw anybody off if not known beforehand. I do not have good examples of industrial-grade Prolog code bases, if that's what was asked.