Copyright	(c) Alexey Kuleshevich 2020
License	BSD3
Maintainer	Alexey Kuleshevich <[email protected]>
Stability	experimental
Portability	non-portable
Safe Haskell	None
Language	Haskell2010

Control.Prim.Monad.Throw

Description

Synopsis

class Monad m => MonadThrow m where
- throwM :: Exception e => e -> m a

Documentation

class Monad m => MonadThrow m where Source #

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 Source #

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

Instances details

MonadThrow Maybe Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e => e -> Maybe a Source #
MonadThrow IO Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e => e -> IO a Source #
MonadThrow STM Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e => e -> STM a Source #
e ~ SomeException => MonadThrow (Either e) Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e0 => e0 -> Either e a Source #
MonadThrow (ST s) Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e => e -> ST s a Source #
Monad m => MonadThrow (MaybeT m) Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e => e -> MaybeT m a Source #
(Monoid w, MonadThrow m) => MonadThrow (WriterT w m) Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e => e -> WriterT w m a Source #
(Monoid w, MonadThrow m) => MonadThrow (AccumT w m) Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e => e -> AccumT w m a Source #
(Monoid w, MonadThrow m) => MonadThrow (WriterT w m) Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e => e -> WriterT w m a Source #
MonadThrow m => MonadThrow (WriterT w m) Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e => e -> WriterT w m a Source #
MonadThrow m => MonadThrow (StateT s m) Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e => e -> StateT s m a Source #
MonadThrow m => MonadThrow (StateT s m) Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e => e -> StateT s m a Source #
MonadThrow m => MonadThrow (SelectT r m) Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e => e -> SelectT r m a Source #
MonadThrow m => MonadThrow (ReaderT r m) Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e => e -> ReaderT r m a Source #
MonadThrow m => MonadThrow (IdentityT m) Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e => e -> IdentityT m a Source #
(e ~ SomeException, Monad m) => MonadThrow (ExceptT e m) Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e0 => e0 -> ExceptT e m a Source #
MonadThrow m => MonadThrow (ContT r m) Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e => e -> ContT r m a Source #
(Monoid w, MonadThrow m) => MonadThrow (RWST r w s m) Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e => e -> RWST r w s m a Source #
(Monoid w, MonadThrow m) => MonadThrow (RWST r w s m) Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e => e -> RWST r w s m a Source #
MonadThrow m => MonadThrow (RWST r w st m) Source #
Instance details Defined in Control.Prim.Monad.Throw Methods throwM :: Exception e => e -> RWST r w st m a Source #