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{- Simple IO exception handling
-
- Copyright 2011-2012 Joey Hess <joey@kitenet.net>
-
- Licensed under the GNU GPL version 3 or higher.
-}
module Utility.Exception where
import Prelude hiding (catch)
import Control.Exception
import Control.Applicative
{- Catches IO errors and returns a Bool -}
catchBoolIO :: IO Bool -> IO Bool
catchBoolIO a = catchDefaultIO a False
{- Catches IO errors and returns a Maybe -}
catchMaybeIO :: IO a -> IO (Maybe a)
catchMaybeIO a = catchDefaultIO (Just <$> a) Nothing
{- Catches IO errors and returns a default value. -}
catchDefaultIO :: IO a -> a -> IO a
catchDefaultIO a def = catchIO a (const $ return def)
{- Catches IO errors and returns the error message. -}
catchMsgIO :: IO a -> IO (Either String a)
catchMsgIO a = dispatch <$> tryIO a
where
dispatch (Left e) = Left $ show e
dispatch (Right v) = Right v
{- catch specialized for IO errors only -}
catchIO :: IO a -> (IOException -> IO a) -> IO a
catchIO = catch
{- try specialized for IO errors only -}
tryIO :: IO a -> IO (Either IOException a)
tryIO = try
|
