Data.Fallible

Documentation

class Applicative f => Fallible f where

Types that may contain failures.

Associated Types

type Failure f :: *

Methods

tryFallible :: f a -> Either (Failure f) a

Get a success or a failure.

tryFallible (pure a) ≡ Right a

Instances

Fallible Maybe

Defined in Data.Fallible

Associated Types

type Failure Maybe :: Type

Methods

tryFallible :: Maybe a -> Either (Failure Maybe) a

Fallible Identity

Defined in Data.Fallible

Associated Types

type Failure Identity :: Type

Methods

tryFallible :: Identity a -> Either (Failure Identity) a

Fallible (Either e)

Defined in Data.Fallible

Associated Types

type Failure (Either e) :: Type

Methods

tryFallible :: Either e a -> Either (Failure (Either e)) a

Fallible (Proxy :: Type -> Type)

Defined in Data.Fallible

Associated Types

type Failure Proxy :: Type

Methods

tryFallible :: Proxy a -> Either (Failure Proxy) a

Monoid e => Fallible (Const e :: Type -> Type)

Defined in Data.Fallible

Associated Types

type Failure (Const e) :: Type

Methods

tryFallible :: Const e a -> Either (Failure (Const e)) a

(??=) :: (Applicative f, Fallible t) => t a -> (Failure t -> f a) -> f a infixl 1

(???) :: (Applicative f, Fallible t) => t a -> f a -> f a infixl 1

(!?=) :: (Monad m, Fallible t) => m (t a) -> (Failure t -> m a) -> m a infixl 1

(!??) :: (Monad m, Fallible t) => m (t a) -> m a -> m a infixl 1

catchFailure :: (Monad m, Fallible t) => m (t a) -> (Failure t -> m a) -> m a

catchFailure_ :: (Monad m, Fallible t) => m (t a) -> m a -> m a

exit :: m r -> ContT r m a

exitA :: Applicative m => r -> ContT r m a

module Control.Monad.Trans.Cont

lift :: (MonadTrans t, Monad m) => m a -> t m a

Lift a computation from the argument monad to the constructed monad.