Advanced Functional Programming with Elixir
Advanced Functional Programming with Elixir turned out to be a pretty good, easy introduction to functional programming concepts, and it uses good domain examples instead of math. It walks through Elixir’s protocol system with a DDD slant, using a theme park domain with rides, patrons, and Fast Passes instead of the numbers-only examples you get in most Haskell books. The code is built around a companion library called FunPark, a teaching-scale version of Koski’s real production package, Funx. The theme park was a good choice, and it paid off most in the Eq/FastPass chapter, where a real business rule (two Fast Passes with the same datetime conflict, but should still be equal by id) motivated contramap far better than an abstract definition ever could have. ...