Maintaining complex state in Haskell

Question

Suppose you\'re building a fairly large simulation in Haskell. There are many different types of entities whose attributes update as the simulation progresses. Let\'s say, f

Answer 1

I know this is old topic. But I am facing the same problem right now while trying to implement Rail Fence cipher exercise from exercism.io. It is quite disappointing to see such a common problem having such poor attention in Haskell. I don't take it that to do some as simple as maintaining state I need to learn FRP. So, I continued googling and found solution looking more straightforward - State monad: https://en.wikibooks.org/wiki/Haskell/Understanding_monads/State