Maybe - BHC Documentation

newtype MaybeT m a { } #

MaybeT { runMaybeT :: m (Maybe a) }

<*> :: { } #

>>= :: { } #

<|> :: { } #

mapMaybeT :: ((m (Maybe a)) -> n (Maybe b)) -> (MaybeT m a) -> MaybeT n b { } #

Transform the computation inside a MaybeT.

maybeToExceptT :: (Functor m) => e -> (MaybeT m a) -> ExceptT e m a { } #

Convert a MaybeT<a> to an ExceptT<a>.

Lift a Maybe<a> into a MaybeT<a>.

Lift a Maybe<a> into any MonadPlus<a>.

instance MonadTrans MaybeT { }

instance MonadIO m => MonadIO (MaybeT m) { }

instance Monad m => MonadPlus (MaybeT m) { }

instance Foldable m => Foldable (MaybeT m) { }

instance Traversable m => Traversable (MaybeT m) { }