ghc-6.10.1: The GHC APIContentsIndex
Exception
Synopsis
catchIO :: IO a -> (IOException -> IO a) -> IO a
handleIO :: (IOException -> IO a) -> IO a -> IO a
tryIO :: IO a -> IO (Either IOException a)
class Monad m => ExceptionMonad m where
gcatch :: Exception e => m a -> (e -> m a) -> m a
gblock :: m a -> m a
gunblock :: m a -> m a
gbracket :: m a -> (a -> m b) -> (a -> m c) -> m c
gfinally :: m a -> m b -> m a
gtry :: (ExceptionMonad m, Exception e) => m a -> m (Either e a)
ghandle :: (ExceptionMonad m, Exception e) => (e -> m a) -> m a -> m a
gonException :: ExceptionMonad m => m a -> m b -> m a
Documentation
catchIO :: IO a -> (IOException -> IO a) -> IO a
handleIO :: (IOException -> IO a) -> IO a -> IO a
tryIO :: IO a -> IO (Either IOException a)
class Monad m => ExceptionMonad m where

A monad that can catch exceptions. A minimal definition requires a definition of gcatch.

Implementations on top of IO should implement gblock and gunblock to eventually call the primitives block and unblock respectively. These are used for implementations that support asynchronous exceptions. The default implementations of gbracket and gfinally use gblock and gunblock thus rarely require overriding.

Methods
gcatch :: Exception e => m a -> (e -> m a) -> m a
Generalised version of catch, allowing an arbitrary exception handling monad instead of just IO.
gblock :: m a -> m a
Generalised version of block, allowing an arbitrary exception handling monad instead of just IO.
gunblock :: m a -> m a
Generalised version of unblock, allowing an arbitrary exception handling monad instead of just IO.
gbracket :: m a -> (a -> m b) -> (a -> m c) -> m c
Generalised version of bracket, allowing an arbitrary exception handling monad instead of just IO.
gfinally :: m a -> m b -> m a
Generalised version of finally, allowing an arbitrary exception handling monad instead of just IO.
show/hide Instances
gtry :: (ExceptionMonad m, Exception e) => m a -> m (Either e a)
ghandle :: (ExceptionMonad m, Exception e) => (e -> m a) -> m a -> m a
Generalised version of handle, allowing an arbitrary exception handling monad instead of just IO.
gonException :: ExceptionMonad m => m a -> m b -> m a
Always executes the first argument. If this throws an exception the second argument is executed and the exception is raised again.
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