Module

# Data.Functor.Contravariant

- Package
- purescript-contravariant
- Repository
- purescript/purescript-contravariant

### #Contravariant Source

`class Contravariant f where`

A `Contravariant`

functor can be seen as a way of changing the input type
of a consumer of input, in contrast to the standard covariant `Functor`

that can be seen as a way of changing the output type of a producer of
output.

`Contravariant`

instances should satisfy the following laws:

- Identity
`cmap id = id`

- Composition
`cmap f <<< cmap g = cmap (g <<< f)`

#### Members

`cmap :: forall a b. (b -> a) -> f a -> f b`

#### Instances

`Contravariant (Const a)`

### #cmapFlipped Source

`cmapFlipped :: forall a b f. Contravariant f => f a -> (b -> a) -> f b`

`cmapFlipped`

is `cmap`

with its arguments reversed.

### #(>#<) Source

Operator alias for Data.Functor.Contravariant.cmapFlipped *(left-associative / precedence 4)*

### #coerce Source

`coerce :: forall f a b. Contravariant f => Functor f => f a -> f b`

### #imapC Source

`imapC :: forall f a b. Contravariant f => (a -> b) -> (b -> a) -> f a -> f b`

As all `Contravariant`

functors are also trivially `Invariant`

, this function can be used as the `imap`

implementation for any types that have an existing `Contravariant`

instance.