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> Pure functions are best of course, but you can't build real-world things entirely from pure functions. That's just plain wrong. There's even a language buil

by louthy 2y ago

> Pure functions are best of course, but you can't build real-world things entirely from pure functions. That's just plain wrong. There's even a language built entirely around pure functions: Haskell.

flohofwoe 2y ago
How do you talk to typical OS-, IO- or GUI-APIs (which all essentially represent global mutable state) in Haskell with pure functional code?
- louthy 2y ago
  via the IO monad.
- IsTom 2y ago
  A toy mental model could be e.g. a function that takes OS/IO/GUI events and produces actions (which are then executed by the caller) and then iterate it as long as the program runs. This function in itself can be pure.