module Test.QuickCheck.Exception where
#if !defined(__GLASGOW_HASKELL__) || (__GLASGOW_HASKELL__ < 609)
#define OLD_EXCEPTIONS
#endif
#if defined(__GLASGOW_HASKELL__) && __GLASGOW_HASKELL__ >= 607
#define GHC_INTERRUPT
#if __GLASGOW_HASKELL__ < 613
#define GHCI_INTERRUPTED_EXCEPTION
#endif
#endif
#if defined(OLD_EXCEPTIONS)
import Control.Exception(evaluate, try, Exception(..), throw)
#else
import Control.Exception.Extensible(evaluate, try, SomeException(SomeException), ErrorCall(..), throw
#if defined(GHC_INTERRUPT)
, AsyncException(UserInterrupt)
#endif
)
#endif
#if defined(GHC_INTERRUPT)
#if defined(GHCI_INTERRUPTED_EXCEPTION)
import Panic(GhcException(Interrupted))
#endif
import Data.Typeable
#if defined(OLD_EXCEPTIONS)
import Data.Dynamic
#endif
#endif
#if defined(OLD_EXCEPTIONS)
type AnException = Control.Exception.Exception
#else
type AnException = SomeException
#endif
tryEvaluate :: a -> IO (Either AnException a)
tryEvaluate x = tryEvaluateIO (return x)
tryEvaluateIO :: IO a -> IO (Either AnException a)
tryEvaluateIO m = try (m >>= evaluate)
isInterrupt :: AnException -> Bool
#if defined(GHC_INTERRUPT)
#if defined(OLD_EXCEPTIONS)
isInterrupt (DynException e) = fromDynamic e == Just Interrupted
isInterrupt _ = False
#elif defined(GHCI_INTERRUPTED_EXCEPTION)
isInterrupt (SomeException e) =
cast e == Just Interrupted || cast e == Just UserInterrupt
#else
isInterrupt (SomeException e) = cast e == Just UserInterrupt
#endif
#else /* !defined(GHC_INTERRUPT) */
isInterrupt _ = False
#endif
discard :: a
isDiscard :: AnException -> Bool
(discard, isDiscard) = (throw (ErrorCall msg), isDiscard)
where
msg = "DISCARD. " ++
"You should not see this exception, it is internal to QuickCheck."
#if defined(OLD_EXCEPTIONS)
isDiscard (ErrorCall msg') = msg' == msg
isDiscard _ = False
#else
isDiscard (SomeException e) =
case cast e of
Just (ErrorCall msg') -> msg' == msg
_ -> False
#endif