Are there languages that include the strong type checking, inference, and typeclass functionality of Haskell while also being a little more forgiving in terms of purity, so that writing ordinary programs is not quite so troublesome as in Haskell?
Rust has a decent amount of type inference, traits and strong guarantees.
Ocaml/SML are both functional languages similar to haskell, and allow IO pretty much anywhere. They don't have typeclasses, (although ML people would say there's nothing you can't do with the ML module system[0]).
