Accesses can be distinguished too - read and write accesses are different. You can see this in [1] - there are Reader and Writer monads, where Reader is used fo

Accesses can be distinguished too - read and write accesses are different. You can see this in [1] - there are Reader and Writer monads, where Reader is used for effectively unchangeable parameter to a monadic context (for example, socket) and Writer is used, among other things, for logging!