Portability | portable |
---|---|
Stability | experimental |
Maintainer | libraries@haskell.org |
Control.Monad.Trans.Maybe
Description
Declaration of the MaybeT
monad transformer.
- newtype MaybeT m a = MaybeT {}
- mapMaybeT :: (m (Maybe a) -> n (Maybe b)) -> MaybeT m a -> MaybeT n b
- liftCallCC :: (((Maybe a -> m (Maybe b)) -> m (Maybe a)) -> m (Maybe a)) -> ((a -> MaybeT m b) -> MaybeT m a) -> MaybeT m a
- liftCatch :: (m (Maybe a) -> (e -> m (Maybe a)) -> m (Maybe a)) -> MaybeT m a -> (e -> MaybeT m a) -> MaybeT m a
- liftListen :: Monad m => (m (Maybe a) -> m (Maybe a, w)) -> MaybeT m a -> MaybeT m (a, w)
- liftPass :: Monad m => (m (Maybe a, w -> w) -> m (Maybe a)) -> MaybeT m (a, w -> w) -> MaybeT m a
The MaybeT monad transformer
Lifting other operations
liftCallCC :: (((Maybe a -> m (Maybe b)) -> m (Maybe a)) -> m (Maybe a)) -> ((a -> MaybeT m b) -> MaybeT m a) -> MaybeT m aSource
Lift a callCC
operation to the new monad.
liftCatch :: (m (Maybe a) -> (e -> m (Maybe a)) -> m (Maybe a)) -> MaybeT m a -> (e -> MaybeT m a) -> MaybeT m aSource
Lift a catchError
operation to the new monad.