module Foundation.Monad.Exception
( MonadFailure(..)
, MonadThrow(..)
, MonadCatch(..)
) where
import Foundation.Internal.Base
import qualified Control.Exception (throwIO, catch)
class Monad m => MonadFailure m where
type Failure m
mFail :: Failure m -> m ()
class Monad m => MonadThrow m where
throw :: Exception e => e -> m a
class MonadThrow m => MonadCatch m where
catch :: Exception e => m a -> (e -> m a) -> m a
instance MonadFailure Maybe where
type Failure Maybe = ()
mFail _ = Nothing
instance MonadFailure (Either a) where
type Failure (Either a) = a
mFail a = Left a
instance MonadThrow IO where
throw = Control.Exception.throwIO
instance MonadCatch IO where
catch = Control.Exception.catch