Excellent answer. I kind of suspected the same but I couldn't quite
find an appropriate translation for "=>".
It's not really implication though. At least not in the same sense as "->". :(
On 29/04/2016, Daniel Bergey
My understanding is that both the -> and => arrows represent implication, in the Curry-Howard view of types as proofs. Maybe someone else can provide better examples of translating back and forth this way. (snip) A class definition with a superclass requirement means something like:
Functor f => Applicative f where ...
You can show that a type f is an Applicative by providing a proof (type class instance) that f is a Functor, and proofs (definitions) of the following class functions.
I hope this helps, and that I've gotten it right.
bergey