> A double arrow => describes constraints on the type variables used, and always come first: add1 :: Num a => a -> a describes a function which takes any type a which satisfies Num a, and returns a value of the same type.
Here, I don't understand what `Num a` syntax means. It was not defined before.
And, what does "satisfies" mean? It is also not defined before it is used. (It is also never mentioned again in the article.) It is maddening to read such sloppily constructed prose. Define your terms before you use them!
> A double arrow => describes constraints on the type variables used, and always come first: add1 :: Num a => a -> a describes a function which takes any type a which satisfies Num a, and returns a value of the same type.
Here, I don't understand what `Num a` syntax means. It was not defined before. And, what does "satisfies" mean? It is also not defined before it is used. (It is also never mentioned again in the article.) It is maddening to read such sloppily constructed prose. Define your terms before you use them!