[zoomerang]

Monadic futures are a fairly effective solution to the problem.

No callback hell, just a clean linear flow of imperative looking non-blocking code that runs concurrently but still guarantees order of execution.

[seanmcdirmid]

Haskell is nothing but indirect action (lazy evaluation...), which is why referential transparency is so important to the language.

[codygman]

In my experience referential transparency increases simplicity and readability in most languages.

[seanmcdirmid]

Yes, but so does keeping your code first order, avoiding callback functions even without the hazard of side effects.