Types of types: Haskell's Kind system

Automated excerpt

What if we replaced the Type param in Type -> Type with (Type -> Type)? Well, for starters, we get a signature like (Type -> Type) -> Type. Just as functions with signatures like (Int -> Int) -> Bool are called higher-order functions, type constructors with Kinds like (Type -> Type) -> Type or (Type -> Type) -> (Type -> Type) -> Type are collectively called higher-Kinded types or HKTs for short.

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