Mini.Transformers.EitherT

Extend a monad with the ability to terminate a computation with a value

Type

newtype EitherT e m a

A terminable transformer with termination e, inner monad m, return a

Constructors

EitherT (m (Either e a))

Instances

MonadTrans (EitherT e)

Defined in Mini.Transformers.EitherT

Methods

lift :: Monad m => m a -> EitherT e m a

MonadFail m => MonadFail (EitherT e m)

Defined in Mini.Transformers.EitherT

Methods

fail :: String -> EitherT e m a

MonadIO m => MonadIO (EitherT e m)

Defined in Mini.Transformers.EitherT

Methods

liftIO :: IO a -> EitherT e m a

(Monad m, Monoid e) => Alternative (EitherT e m)

Defined in Mini.Transformers.EitherT

Methods

empty :: EitherT e m a

(<|>) :: EitherT e m a -> EitherT e m a -> EitherT e m a

some :: EitherT e m a -> EitherT e m [a]

many :: EitherT e m a -> EitherT e m [a]

Monad m => Applicative (EitherT e m)

Defined in Mini.Transformers.EitherT

Methods

pure :: a -> EitherT e m a

(<*>) :: EitherT e m (a -> b) -> EitherT e m a -> EitherT e m b

liftA2 :: (a -> b -> c) -> EitherT e m a -> EitherT e m b -> EitherT e m c

(*>) :: EitherT e m a -> EitherT e m b -> EitherT e m b

(<*) :: EitherT e m a -> EitherT e m b -> EitherT e m a

Monad m => Functor (EitherT e m)

Defined in Mini.Transformers.EitherT

Methods

fmap :: (a -> b) -> EitherT e m a -> EitherT e m b

(<$) :: a -> EitherT e m b -> EitherT e m a

Monad m => Monad (EitherT e m)

Defined in Mini.Transformers.EitherT

Methods

(>>=) :: EitherT e m a -> (a -> EitherT e m b) -> EitherT e m b

(>>) :: EitherT e m a -> EitherT e m b -> EitherT e m b

return :: a -> EitherT e m a

Runner

runEitherT :: EitherT e m a -> m (Either e a)

Unwrap an EitherT computation

Operations

left :: Monad m => e -> EitherT e m a

Terminate the computation with a value

anticipate :: Monad m => EitherT e m a -> EitherT e m (Either e a)

Run a computation and get its result