Do you remember Prolog? If not feel highly encouraged to delve into this '72-ish language. What makes Prolog special and noteworthy, is that it is a declarative language in which the program logic is expressed in terms of relations, represented as facts and rules. After entering those, one can dynamically query the system and have it compute everything that can be successfully derived from the … facts and rules. Cool stuff. And since especially declarative programming is a thing today, you might want to check out the language.

brew install gnu-prolog immediately gives you a runtime environment on a Mac and there are implementations for every red, green and pink processor architecture, that you can imagine. 

If you want to give it a spin, or just need some brain food, you have to join David Strohmaier’s journey to create a solver for standard Sudokus using Prolog.

Be warned, it definitely takes some time, but is absolutely worth the effort.