Functor -package +base

class Functor f
base Prelude, base Data.Functor, base Control.Monad, base Control.Monad.Instances
The Functor class is used for types that can be mapped over. Instances of Functor should satisfy the following laws: > fmap id == id > fmap (f . g) == fmap f . fmap g The instances of Functor for lists, Data.Maybe.Maybe and System.IO.IO satisfy these laws.
module Data.Functor
base Data.Functor
Functors: uniform action over a parameterized type, generalizing the map function on lists.