Control.Comonad.Density

The density comonad for a functor. aka the comonad generated by a functor The ''density'' term dates back to Dubuc''s 1974 thesis. The term ''monad genererated by a functor'' dates back to 1972 in Street''s ''Formal Theory of Monads''.

Documentation

data DensityT k a where

Constructors

DensityT :: (k b -> a) -> k b -> DensityT k a

Instances

ComonadTrans DensityT

Functor (DensityT f)

Comonad (DensityT f)

Extend (DensityT f)

liftDensityT :: Comonad w => w a -> DensityT w a

The natural isomorphism between a comonad w and the comonad generated by w (forwards).

densityTToAdjunction :: Adjunction f g => DensityT f a -> f (g a)

adjunctionToDensityT :: Adjunction f g => f (g a) -> DensityT f a