Control.Prim.Monad.Throw

Documentation

class Monad m => MonadThrow m where

A class for monads in which exceptions may be thrown.

Instances should obey the following law:

throwM e >> x = throwM e

In other words, throwing an exception short-circuits the rest of the monadic computation.

Note

This is an identical class to MonadThrow from exceptions package. The reason why it was copied, instead of a direct dependency on the aforementioned package is because MonadCatch and MonadMask are not right abstractions for exception handling in presence of concurrency and also because instances for such transformers as MaybeT and ExceptT are flawed.

Methods

throwM :: Exception e => e -> m a

Throw an exception. Note that this throws when this action is run in the monad m, not when it is applied. It is a generalization of Control.Prim.Exception's throw.

Instances

MonadThrow Maybe

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e => e -> Maybe a

MonadThrow IO

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e => e -> IO a

MonadThrow STM

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e => e -> STM a

e ~ SomeException => MonadThrow (Either e)

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e0 => e0 -> Either e a

MonadThrow (ST s)

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e => e -> ST s a

Monad m => MonadThrow (MaybeT m)

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e => e -> MaybeT m a

(Monoid w, MonadThrow m) => MonadThrow (WriterT w m)

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e => e -> WriterT w m a

(Monoid w, MonadThrow m) => MonadThrow (AccumT w m)

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e => e -> AccumT w m a

(Monoid w, MonadThrow m) => MonadThrow (WriterT w m)

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e => e -> WriterT w m a

MonadThrow m => MonadThrow (WriterT w m)

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e => e -> WriterT w m a

MonadThrow m => MonadThrow (StateT s m)

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e => e -> StateT s m a

MonadThrow m => MonadThrow (StateT s m)

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e => e -> StateT s m a

MonadThrow m => MonadThrow (SelectT r m)

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e => e -> SelectT r m a

MonadThrow m => MonadThrow (ReaderT r m)

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e => e -> ReaderT r m a

MonadThrow m => MonadThrow (IdentityT m)

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e => e -> IdentityT m a

(e ~ SomeException, Monad m) => MonadThrow (ExceptT e m)

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e0 => e0 -> ExceptT e m a

MonadThrow m => MonadThrow (ContT r m)

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e => e -> ContT r m a

(Monoid w, MonadThrow m) => MonadThrow (RWST r w s m)

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e => e -> RWST r w s m a

(Monoid w, MonadThrow m) => MonadThrow (RWST r w s m)

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e => e -> RWST r w s m a

MonadThrow m => MonadThrow (RWST r w st m)

Defined in Control.Prim.Monad.Throw

Methods

throwM :: Exception e => e -> RWST r w st m a