Control.Monad.Failure

Defines the class MonadFailure for monads which can fail.

Documentation

class Monad m => MonadFailure e m where

Methods

failure :: e -> m a

Instances

Exception e => MonadFailure e IO

MonadFailure e []

MonadFailure e Maybe

MonadFailure e m => MonadFailure e (ListT m)

Error e => MonadFailure e (Either e)

MonadFailure e m => MonadFailure e (StateT s m)

(Monoid w, MonadFailure e m) => MonadFailure e (WriterT w m)

MonadFailure e m => MonadFailure e (ReaderT r m)

(Error e, Monad m) => MonadFailure e (ErrorT e m)

(Monoid w, MonadFailure e m) => MonadFailure e (RWST r w s m)