IO exception rework

ghc 7.4 comaplains about use of System.IO.Error to catch exceptions.
Ok, use Control.Exception, with variants specialized to only catch IO
exceptions.
This commit is contained in:
Joey Hess 2012-02-03 16:47:24 -04:00
parent 05f89123e0
commit 146c36ca54
14 changed files with 56 additions and 44 deletions

View file

@ -8,9 +8,7 @@
module Utility.Misc where
import System.IO
import System.IO.Error (try)
import Control.Monad
import Control.Applicative
{- A version of hgetContents that is not lazy. Ensures file is
- all read before it gets closed. -}
@ -37,22 +35,3 @@ separate c l = unbreak $ break c l
{- Breaks out the first line. -}
firstLine :: String-> String
firstLine = takeWhile (/= '\n')
{- 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 = catch a (const $ return def)
{- Catches IO errors and returns the error message. -}
catchMsgIO :: IO a -> IO (Either String a)
catchMsgIO a = dispatch <$> try a
where
dispatch (Left e) = Left $ show e
dispatch (Right v) = Right v