wambook

I started learning prolog just a few months ago, when I stumbled upon https://linusakesson.net/dialog/ which is a spin on prolog optimized for writing interactive fiction. As a sweet and short tutorial I can recommend these slides: https://www.cs.toronto.edu/~hojjat/384w10/ If you want to dive into how Prolog works under the hood I can recommend https://github.com/a-yiorgos/wambook I terms of Prolog implementations I played a bit with https://www.scryer.pl but it still feels rough around the edges. SWI-Prolog is the most popular and most batteries included Prolog: https://www.swi-prolog.org With its libraries and documentation it is a very practical language. What surprised me is, that you can easily produce amazingly small stand-alone binaries.

It is worth noting that lots of applications of unification do not reify explicit substitutions in their implementations. You often see introductory type inference articles (usually focused on Hindley-Milner) use algorithm W, which uses a unification procedure that returns substitutions (which must then be composed with other substitutions). All of this is less efficient and arguably more error-prone and more complicated than the destructive unification implied by algorithm J (using the union-find data structure, often implemented invasively into the type representation to imply a union-find forest). To this end, good coverage of decent (destructive) unification algorithms can be found in any simple resource on type inference (https://okmij.org/ftp/ML/generalization/sound_eager.ml) or the Warren Abstract Machine (https://github.com/a-yior