Much to their ultimate chagrin, I reviewed a book that a friend of mine had backed via patreon. The book mirrored a little bit of what Norvig wrote in the 90s, in Paradigms of Artificial Intelligence in Practice. Norvig's book is an interesting piece of historical history, only valuable now for his views on high value programming technique in a serious language. One thing Norvig took pains to achieve throughout the book was a finished implementation of prolog in common lisp which was then reattempted by Paul Graham, from the more engineering-side lisp hackers. In every case, the motivation given was that prolog is a perfect domain specific language: Hard to improve on by substantively changing, just like common lisp. Prolog is basically a continuation-passing implementation of a graph search on input facts. Prolog won't do anything else; that's why you would want both it and your favourite hacking language in the same program. But with independently world-famous lisp authors taking prolog as a DSL in lisp so seriously, why did it never catch on (except for at Allegro and Lispworks) ? I think I stumbled across the answer. It's that #'continuation-based-prolog-graph-search is not in the standard nor in #:alexandria. Re-imagining a complete prolog from the ground up both deviates wildly out from common lisp, which we know is a hard place to find improvements from the last 40 years, and trying to beat prolog at its own game, which would also be a first(ish). I'm getting cold feet as I finish writing this, but I think reimaginings of what common lisp should be like die off.