[asmala]

I think you're absolutely right that functional programming is particularly suited for things like mathematics. But you can also enjoy many of the benefits of a functional approach by moving most of the complexity into purely functional, well, functions and leaving the state-modifying code fairly simple. For a good pragmatic example of this approach, check out the snake game in Programming Clojure v2 from Pragmatic Programmers.

Coming from Ruby this approach was a bit mind-boggling at first, but even with my fairly limited Clojure exposure (or should that be expojure?) I've come to appreciate how easy pure functions are to test and to reason about.