Stability | experimental |
---|---|
Maintainer | ekmett@gmail.com |
Safe Haskell | None |
Representable contravariant endofunctors over the category of Haskell
types are isomorphic to (_ -> r)
and resemble mappings to a
fixed range.
- type family Value f
- class Contravariant f => Valued f where
- contramapWithValue :: (b -> Either a (Value f)) -> f a -> f b
- class Coindexed f where
- class (Coindexed f, Valued f) => Representable f where
- contramapDefault :: Representable f => (a -> b) -> f b -> f a
- contramapWithValueDefault :: Representable f => (b -> Either a (Value f)) -> f a -> f b
Values
Contravariant Keyed
class Contravariant f => Valued f whereSource
Dual to Keyed
.
contramapWithValue :: (b -> Either a (Value f)) -> f a -> f bSource
Contravariant Indexed
Dual to Indexed
.
Representable Contravariant Functors
class (Coindexed f, Valued f) => Representable f whereSource
A Contravariant
functor f
is Representable
if contrarep
and coindex
witness an isomorphism to (_ -> Value f)
.
Representable Predicate | |
Representable (Op r) | |
(Representable f, Representable g) => Representable (Product f g) |
Default definitions
contramapDefault :: Representable f => (a -> b) -> f b -> f aSource
contramapWithValueDefault :: Representable f => (b -> Either a (Value f)) -> f a -> f bSource