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

Typeclasses like Monad, Applicative, Arrow, Functor are great and all, and even more great for changing how you think about code than necessarily the convenience of having functions generic over them. But there's a common misconception that the "next step" in Haskell is learning about more typeclasses and ways of structuring control flow. The next step is in deciding what you want to write, and trying to write it, exploring what you need along the way.

And even if you understand Monads, that doesn't mean you've scratched the surface of what you can do with monadically structured code. Play with parser combinator libraries, or write your own. Explore why applicative notation is sometimes easier for them. Explore why limiting yourself to applicative parsers might be more efficient.

Look at logic or math problems and explore ways of implementing backtracking -- depth-first, breadth-first, etc. Explore the difference between ListT and LogicT and ChoiceT. Take a look at continuations.

Or do something completely different!