Purely Functional, Declarative Game Logic Using Reactive Programming

"In the previous article I introduced the Coroutine data type. In this second part I will show how coroutines can be used to implement a fixed time-step reactive programming library and use that library for modeling a simple game. The code examples will require a basic proficiency in reading Haskell code." https://github.com/leonidas/codeblog/blob/master/2012/2012-01-17-declarative-game-logic-afrp.md