-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | Type classes and monads for unchecked extensible exceptions.
--   
--   This package provides type classes, a monad and a monad transformer
--   that support unchecked extensible exceptions as well as asynchronous
--   exceptions. It is compatible with the transformers package.
@package exception-transformers
@version 0.4.0.9


module Control.Monad.Exception
class (Typeable e, Show e) => Exception e
toException :: Exception e => e -> SomeException
fromException :: Exception e => SomeException -> Maybe e
displayException :: Exception e => e -> String
data SomeException
class (Monad m) => MonadException m

-- | Throw an exception.
throw :: (MonadException m, Exception e) => e -> m a

-- | Catch an exception.
catch :: (MonadException m, Exception e) => m a -> (e -> m a) -> m a

-- | Run a computation and always perform a second, final computation even
--   if an exception is raised. If a short-circuiting monad transformer
--   such as ErrorT or MaybeT is used to transform a MonadException monad,
--   then the implementation of <tt>finally</tt> for the transformed monad
--   must guarantee that the final action is also always performed when any
--   short-circuiting occurs.
finally :: MonadException m => m a -> m b -> m a

-- | If an exception is raised by the computation, then perform a final
--   action and re-raise the exception.
onException :: MonadException m => m a -> m b -> m a
class (MonadIO m, MonadException m) => MonadAsyncException m

-- | Executes a computation with asynchronous exceptions <i>masked</i>. The
--   argument passed to <a>mask</a> is a function that takes as its
--   argument another function, which can be used to restore the prevailing
--   masking state within the context of the masked computation.
mask :: MonadAsyncException m => ((forall a. m a -> m a) -> m b) -> m b

-- | When you want to acquire a resource, do some work with it, and then
--   release the resource, it is a good idea to use <a>bracket</a>, because
--   <a>bracket</a> will install the necessary exception handler to release
--   the resource in the event that an exception is raised during the
--   computation. If an exception is raised, then <a>bracket</a> will
--   re-raise the exception (after performing the release).
bracket :: MonadAsyncException m => m a -> (a -> m b) -> (a -> m c) -> m c

-- | A variant of <a>bracket</a> where the return value from the first
--   computation is not required.
bracket_ :: MonadAsyncException m => m a -> m b -> m c -> m c
newtype ExceptionT m a
ExceptionT :: m (Either SomeException a) -> ExceptionT m a
[runExceptionT] :: ExceptionT m a -> m (Either SomeException a)
mapExceptionT :: (m (Either SomeException a) -> n (Either SomeException b)) -> ExceptionT m a -> ExceptionT n b

-- | Lift the result of running a computation in a monad transformed by
--   <a>ExceptionT</a> into another monad that supports exceptions.
liftException :: MonadException m => Either SomeException a -> m a
instance Control.Monad.Trans.Class.MonadTrans Control.Monad.Exception.ExceptionT
instance (GHC.Base.Functor m, GHC.Base.Monad m) => GHC.Base.Applicative (Control.Monad.Exception.ExceptionT m)
instance GHC.Base.Functor m => GHC.Base.Functor (Control.Monad.Exception.ExceptionT m)
instance GHC.Base.Monad m => GHC.Base.Monad (Control.Monad.Exception.ExceptionT m)
instance GHC.Base.Monad m => Control.Monad.Fail.MonadFail (Control.Monad.Exception.ExceptionT m)
instance GHC.Base.Monad m => GHC.Base.MonadPlus (Control.Monad.Exception.ExceptionT m)
instance (GHC.Base.Functor m, GHC.Base.Monad m) => GHC.Base.Alternative (Control.Monad.Exception.ExceptionT m)
instance Control.Monad.Fix.MonadFix m => Control.Monad.Fix.MonadFix (Control.Monad.Exception.ExceptionT m)
instance GHC.Base.Monad m => Control.Monad.Exception.MonadException (Control.Monad.Exception.ExceptionT m)
instance Control.Monad.IO.Class.MonadIO m => Control.Monad.IO.Class.MonadIO (Control.Monad.Exception.ExceptionT m)
instance Control.Monad.Exception.MonadAsyncException m => Control.Monad.Exception.MonadAsyncException (Control.Monad.Exception.ExceptionT m)
instance Control.Monad.Exception.MonadAsyncException GHC.Types.IO
instance (Control.Monad.Exception.MonadAsyncException m, Control.Monad.Trans.Error.Error e) => Control.Monad.Exception.MonadAsyncException (Control.Monad.Trans.Error.ErrorT e m)
instance Control.Monad.Exception.MonadAsyncException m => Control.Monad.Exception.MonadAsyncException (Control.Monad.Trans.Except.ExceptT e' m)
instance Control.Monad.Exception.MonadAsyncException m => Control.Monad.Exception.MonadAsyncException (Control.Monad.Trans.Identity.IdentityT m)
instance Control.Monad.Exception.MonadAsyncException m => Control.Monad.Exception.MonadAsyncException (Control.Monad.Trans.List.ListT m)
instance Control.Monad.Exception.MonadAsyncException m => Control.Monad.Exception.MonadAsyncException (Control.Monad.Trans.Maybe.MaybeT m)
instance (GHC.Base.Monoid w, Control.Monad.Exception.MonadAsyncException m) => Control.Monad.Exception.MonadAsyncException (Control.Monad.Trans.RWS.Lazy.RWST r w s m)
instance (GHC.Base.Monoid w, Control.Monad.Exception.MonadAsyncException m) => Control.Monad.Exception.MonadAsyncException (Control.Monad.Trans.RWS.Strict.RWST r w s m)
instance Control.Monad.Exception.MonadAsyncException m => Control.Monad.Exception.MonadAsyncException (Control.Monad.Trans.Reader.ReaderT r m)
instance Control.Monad.Exception.MonadAsyncException m => Control.Monad.Exception.MonadAsyncException (Control.Monad.Trans.State.Lazy.StateT s m)
instance Control.Monad.Exception.MonadAsyncException m => Control.Monad.Exception.MonadAsyncException (Control.Monad.Trans.State.Strict.StateT s m)
instance (GHC.Base.Monoid w, Control.Monad.Exception.MonadAsyncException m) => Control.Monad.Exception.MonadAsyncException (Control.Monad.Trans.Writer.Lazy.WriterT w m)
instance (GHC.Base.Monoid w, Control.Monad.Exception.MonadAsyncException m) => Control.Monad.Exception.MonadAsyncException (Control.Monad.Trans.Writer.Strict.WriterT w m)
instance Control.Monad.Exception.MonadException GHC.Types.IO
instance Control.Monad.Exception.MonadException GHC.Conc.Sync.STM
instance (Control.Monad.Exception.MonadException m, Control.Monad.Trans.Error.Error e) => Control.Monad.Exception.MonadException (Control.Monad.Trans.Error.ErrorT e m)
instance Control.Monad.Exception.MonadException m => Control.Monad.Exception.MonadException (Control.Monad.Trans.Except.ExceptT e' m)
instance Control.Monad.Exception.MonadException m => Control.Monad.Exception.MonadException (Control.Monad.Trans.Identity.IdentityT m)
instance Control.Monad.Exception.MonadException m => Control.Monad.Exception.MonadException (Control.Monad.Trans.List.ListT m)
instance Control.Monad.Exception.MonadException m => Control.Monad.Exception.MonadException (Control.Monad.Trans.Maybe.MaybeT m)
instance (GHC.Base.Monoid w, Control.Monad.Exception.MonadException m) => Control.Monad.Exception.MonadException (Control.Monad.Trans.RWS.Lazy.RWST r w s m)
instance (GHC.Base.Monoid w, Control.Monad.Exception.MonadException m) => Control.Monad.Exception.MonadException (Control.Monad.Trans.RWS.Strict.RWST r w s m)
instance Control.Monad.Exception.MonadException m => Control.Monad.Exception.MonadException (Control.Monad.Trans.Reader.ReaderT r m)
instance Control.Monad.Exception.MonadException m => Control.Monad.Exception.MonadException (Control.Monad.Trans.State.Lazy.StateT s m)
instance Control.Monad.Exception.MonadException m => Control.Monad.Exception.MonadException (Control.Monad.Trans.State.Strict.StateT s m)
instance (GHC.Base.Monoid w, Control.Monad.Exception.MonadException m) => Control.Monad.Exception.MonadException (Control.Monad.Trans.Writer.Lazy.WriterT w m)
instance (GHC.Base.Monoid w, Control.Monad.Exception.MonadException m) => Control.Monad.Exception.MonadException (Control.Monad.Trans.Writer.Strict.WriterT w m)
