Moduleadjunctions-4.4.3Haskell2010

Control.Monad.Trans.Contravariant.Adjoint

Uses a contravariant adjunction:

f -| g : Hask^op -> Hask

to build a Comonad to Monad transformer. Sadly, the dual construction, which builds a Comonad out of a Monad, is uninhabited, because any Adjunction of the form

f -| g : Hask -> Hask^op

would trivially admit unsafePerformIO.

2 types
2 values

Packageadjunctions-4.4.3
Exports4
LanguageHaskell2010
LicenceBSD-2-Clause
SourceAdjoint.hs

typetype Adjoint (f :: Type -> Type) (g :: Type -> Type) = AdjointT f g Identity

valuerunAdjoint :: Contravariant g => Adjoint f g a -> g (f a)

valueadjoint :: Contravariant g => g (f a) -> Adjoint f g a

newtypenewtype AdjointT (f :: Type -> Type) (g :: Type -> Type) (w :: Type -> Type) a

Constructors

AdjointT
- runAdjointT :: g (w (f a))

Instances3Monad, Functor, Applicative

(Adjunction f g, Comonad w) => Monad (AdjointT f g w)Defined in adjunctions-4.4.3 · Control.Monad.Trans.Contravariant.Adjoint
(Adjunction f g, Functor w) => Functor (AdjointT f g w)Defined in adjunctions-4.4.3 · Control.Monad.Trans.Contravariant.Adjoint
(Adjunction f g, Comonad w) => Applicative (AdjointT f g w)Defined in adjunctions-4.4.3 · Control.Monad.Trans.Contravariant.Adjoint