Control.Monad.Trans.Identity

The identity monad transformer.

This is useful for functions parameterized by a monad transformer.

The identity monad transformer

newtype IdentityT f a

The trivial monad transformer, which maps a monad to an equivalent monad.

Constructors

IdentityT (f a)

Instances

MonadTrans IdentityT

Monad m => Monad (IdentityT m)

Functor m => Functor (IdentityT m)

MonadFix m => MonadFix (IdentityT m)

MonadPlus m => MonadPlus (IdentityT m)

Applicative m => Applicative (IdentityT m)

Foldable f => Foldable (IdentityT f)

Traversable f => Traversable (IdentityT f)

Alternative m => Alternative (IdentityT m)

MonadIO m => MonadIO (IdentityT m)

Show1 f => Show1 (IdentityT f)

Read1 f => Read1 (IdentityT f)

Ord1 f => Ord1 (IdentityT f)

Eq1 f => Eq1 (IdentityT f)

(Eq1 f, Eq a) => Eq (IdentityT f a)

(Ord1 f, Ord a) => Ord (IdentityT f a)

(Read1 f, Read a) => Read (IdentityT f a)

(Show1 f, Show a) => Show (IdentityT f a)

runIdentityT :: IdentityT f a -> f a

The inverse of IdentityT.

mapIdentityT :: (m a -> n b) -> IdentityT m a -> IdentityT n b

Lift a unary operation to the new monad.

Lifting other operations

liftCatch :: Catch e m a -> Catch e (IdentityT m) a

Lift a catchE operation to the new monad.

liftCallCC :: CallCC m a b -> CallCC (IdentityT m) a b

Lift a callCC operation to the new monad.