[galaxyLogic]

Right. I was thinking of how to write a game in Haskell or similar. I need to write some kind of loop to keep my program/game running indefinitely. And I need to avoid "blowing up" the stack by writing my program as a set of calls to tail-recursive functions. No?

The program must keep the previous state somewhere and then modify it based on the player's inputs and again store that new state somewhere somehow so it is remembered when next input comes. If loops which keep and modify state are not allowed, then I don't see how it could be done without tail-recursive functions.