> do you know of an easy way to _implement_ prolog?

There are some examples on the Web; I'm not sure about quality, but here is a couple:

1) https://github.com/norvig/paip-lisp/tree/master/lisp

Norvig implements (some pieces of?) Prolog in Lisp in his book (book text is freely available)

2) https://github.com/prolog8/awkprolog

An implementation of Prolog in AWK.