What's the next step to learning Haskell after monads?

Question

I\'ve been gradually learning Haskell, and even feel like I\'ve got a hang of monads. However, there\'s still a lot of more exotic stuff that I barely understand, like Arrows, A

Answer 1

As a single next step (rather than half a dozen "next steps"), I suggest that you learn to write your own type classes. Here are a couple of simple problems to get you started:

• Writing some interesting instance declarations for QuickCheck. Say for example that you want to generate random trees that are in some way "interesting".

• Move on to the following little problem: define functions /\, \/, and complement ("and", "or", & "not") that can be applied not just to Booleans but to predicates of arbitrary arity. (If you look carefully, you can find the answer to this one on SO.)