safe-failure 0.1 → 0.2

raw patch · 2 files changed

+28/−14 lines, 2 filesdep +transformersdep −extensible-exceptionsdep ~base

Dependencies added: transformers

Dependencies removed: extensible-exceptions

Dependency ranges changed: base

Files

• Safe/Failure.hs +25/−0
• safe-failure.cabal +3/−14

@@ -31,6 +31,10 @@ Safe.Failure.read, -- * Useful combinators def, note,+-- * Assertions+Safe.Failure.assert,+-- * IO functions+Safe.Failure.readFile, -- * Exceptions SafeException(..), HeadFailure(..), TailFailure(..), InitFailure(..), LastFailure(..),@@ -45,9 +49,11 @@ import Control.Monad.Failure import Data.Maybe import Data.Typeable+import Control.Monad.Trans #ifdef CME import Control.Monad.Exception.Throws #endif+import Control.Monad (liftM)  {-| @def@, use it to return a default value in the event of an error. @@ -198,6 +204,25 @@ lookup :: (Eq a, MonadFailure (LookupFailure a) m) => a -> [(a,b)] -> m b lookup key = maybe (failure (LookupFailure key)) return . Prelude.lookup key +-- | Assert a value to be true. If true, returns the first value as a succss.+-- Otherwise, returns the second value as a failure.+assert :: (MonadFailure e m, Exception e)+       => Bool+       -> v+       -> e+       -> m v+assert b v e = if b then return v else failure e++-- | The standard readFile function with any 'IOException's returned as a+-- failure instead of a runtime exception.+readFile :: (MonadFailure IOException m, MonadIO m) => FilePath -> m String+readFile fp = do+    contents <- liftIO $ handle+                    (\e -> return $ Left (e :: IOException))+                    (liftM Right $ Prelude.readFile fp)+    case contents of+        Left e -> failure e+        Right v -> return v  #ifdef CME 

@@ -1,7 +1,7 @@ Name:           safe-failure Build-Type:     Simple Cabal-Version:  >= 1.2-Version:        0.1+Version:        0.2 License:        BSD3 License-File:   LICENSE Copyright:      2007-8, Neil Mitchell@@ -9,7 +9,7 @@ Author:         Neil Mitchell, Jose Iborra (2009), Michael Snoyman (2009) Homepage:       http://www-users.cs.york.ac.uk/~ndm/safe/ Category:       Unclassified-Synopsis:       Library for safe functions+Synopsis:       Partial functions from the prelude with a MonadFailure interface Description:     Partial functions from the base library, such as @head@ and @!!@, modified     to fail in a @MonadFailure@ monad.@@ -21,20 +21,9 @@   description: build with special support for control-monad-exception   default: True -Flag extensibleExceptions-  description: Use extensible-exception package-  default: False- Library    buildable: True-   build-depends: control-monad-failure-  if flag(extensibleExceptions)-    build-depends:-      extensible-exceptions >= 0.1 && <0.2,-      base >= 3.0 && <4-  else-    build-depends:-      base >= 4 && < 5+   build-depends:  base >= 4 && < 5, control-monad-failure, transformers    exposed-modules:         Safe.Failure    ghc-options: -Wall