diff options
Diffstat (limited to 'libraries/base/GHC/IO.hs')
| -rw-r--r-- | libraries/base/GHC/IO.hs | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/libraries/base/GHC/IO.hs b/libraries/base/GHC/IO.hs index 9fa0aff929..1e8c74e5c1 100644 --- a/libraries/base/GHC/IO.hs +++ b/libraries/base/GHC/IO.hs @@ -23,7 +23,7 @@ ----------------------------------------------------------------------------- module GHC.IO ( - IO(..), unIO, failIO, liftIO, + IO(..), unIO, failIO, liftIO, mplusIO, unsafePerformIO, unsafeInterleaveIO, unsafeDupablePerformIO, unsafeDupableInterleaveIO, noDuplicate, @@ -45,7 +45,7 @@ import GHC.ST import GHC.Exception import GHC.Show -import {-# SOURCE #-} GHC.IO.Exception ( userError ) +import {-# SOURCE #-} GHC.IO.Exception ( userError, IOError ) -- --------------------------------------------------------------------------- -- The IO Monad @@ -292,6 +292,12 @@ catchAny :: IO a -> (forall e . Exception e => e -> IO a) -> IO a catchAny (IO io) handler = IO $ catch# io handler' where handler' (SomeException e) = unIO (handler e) + +mplusIO :: IO a -> IO a -> IO a +mplusIO m n = m `catchIOError` \ _ -> n + where catchIOError :: IO a -> (IOError -> IO a) -> IO a + catchIOError = catchException + -- | A variant of 'throw' that can only be used within the 'IO' monad. -- -- Although 'throwIO' has a type that is an instance of the type of 'throw', the |