std.functor

[src]

Implementation of the Functor type

Types

#[implicit]
type Functor f = { map : forall a b . (a -> b) -> f a -> f b }

A Functor represents an action on a parameterized type which does not change the structure with the mapped type.

The following laws should hold:

map id == id
map (f << g) == map f << map g

Values

let map ?functor : forall b a f . [Functor f] -> (a -> b) -> f a -> f b

[src]

Apply the supplied function to the contents of f a, converting it to an f b

Examples

option.functor.map show_Int.show (Some 1) == Some "1"
result.functor.map show_Int.show (Some 1) == Ok "1"
list.functor.map show_Int.show (list.of [1, 2]) == list.of ["1", "2"]

Note

Known as fmap in Haskell