Control.Monad.Trans.Identity

The identity monad transformer.

This is useful for functions parameterized by a monad transformer.

The identity monad transformer

newtype IdentityT m a

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

Constructors

IdentityT

Fields

runIdentityT :: m a

Instances

MonadTrans IdentityT

Monad m => Monad (IdentityT m)

Functor m => Functor (IdentityT m)

MonadPlus m => MonadPlus (IdentityT m)

Applicative m => Applicative (IdentityT m)

Alternative m => Alternative (IdentityT m)

MonadIO m => MonadIO (IdentityT m)

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

Lift a unary operation to the new monad.

Lifting other operations

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

Lift a catchError operation to the new monad.

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

Lift a callCC operation to the new monad.