Use these functions to convert between Maybe
, Either
, MaybeT
, and
ExceptT
.
hush :: forall a b. Either a b -> Maybe b
Suppress the Left
value of an Either
hushT :: forall a b m. Monad m => ExceptT a m b -> MaybeT m b
Suppress the Left
value of an ExceptT
note :: forall a b. a -> Maybe b -> Either a b
Tag the Nothing
value of a Maybe
noteT :: forall a b m. Monad m => a -> MaybeT m b -> ExceptT a m b
Tag the Nothing
value of a MaybeT
hoistMaybe :: forall b m. Monad m => Maybe b -> MaybeT m b
Lift a Maybe
to the MaybeT
monad
exceptNoteM :: forall a e m. Applicative m => Maybe a -> e -> ExceptT e m a
Convert a Maybe
value into the ExceptT
monad
infixl 9 exceptNoteM as ??
exceptNoteA :: forall a e m. Apply m => m (Maybe a) -> e -> ExceptT e m a
Convert an applicative Maybe
value into the ExceptT
monad
infixl 9 exceptNoteA as !?
bool :: forall a. a -> a -> Boolean -> a
Case analysis for the Boolean
type
fromMaybe' :: forall a. Maybe a -> a -> a
An infix form of fromMaybe
with arguments flipped.
infixl 9 fromMaybe' as ?: