Safe Haskell | Safe |
---|---|

Language | Haskell2010 |

## Synopsis

- class KFunctor (f :: k) (v :: Variances) (as :: LoT k) (bs :: LoT k) | f -> v where
- kmapo :: forall f v as bs. KFunctor f v as bs => Mappings v as bs -> (f :@@: as) -> f :@@: bs
- data Variance
- type Variances = [Variance]
- type family Mapping (v :: Variance) a b where ...
- data Mappings (v :: Variances) (x :: LoT k) (y :: LoT k) where

# Documentation

class KFunctor (f :: k) (v :: Variances) (as :: LoT k) (bs :: LoT k) | f -> v where Source #

Declares that the type constructor `f`

is a generalized
functor whose variances for each type argument are given by `v`

.

kmapo :: forall f v as bs. KFunctor f v as bs => Mappings v as bs -> (f :@@: as) -> f :@@: bs Source #

The generalized version of `fmap`

, `bimap`

, `dimap`

, and so on.
This version uses `Split`

to obtain better type inference.

## Mappings of different variance

Possible variances for each argument of a type constructor.