FWIW, there's this paper that "[takes] a fresh, 'clean-room' look at implementing Prolog by deriving its translation to an executable representation and its execution algorithm from a simple Horn Clause meta-interpreter."
"A Hitchhiker’s Guide to Reinventing a Prolog Machine" Paul Tarau
https://www.cse.unt.edu/~tarau/research/2017/eng.pdf
Slides: https://software.imdea.org/Conferences/CICLOPS2017/files/tar...