4 ms·

side effects are quite the thorn in this theories side. hard to describe message passing in purely applicative terms.

• nine_k 1y ago
  Effects are pretty smoothly described by monads; there's an entire well-respected language built on top of that. One of the problems of the purely applicative approach is that you get a nice algebra for describing your results, including the sequence of effects, but reasoning about the resources spent by the computation becomes harder.
  • knome 1y ago
    monads were certainly a clever fix for the difficulties otherwise caused by passing around the world as a value. I might argue that laziness makes haskell something different than purely applicative. It's not just pure values being passed around. It's a language built atop suspended self-caching invocable thunks getting knotted up and then firing off in chain reaction. main = do let hello = foo world world = bar hello putStrLn $ show hello putStrLn $ show world where foo v = [v] bar v = length v