X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=Control%2FException.hs;h=cb4ba3e98f7ba384e24f49e051cf8a969bc69018;hb=819adca5f17b40ee129e4a30edf685f817febbf9;hp=20105e8cdd31db9bdc98e7670e2f27c5ca996380;hpb=7dce20a482831cd7a8d8f7d1f6092102d2779504;p=ghc-base.git

diff --git a/Control/Exception.hs b/Control/Exception.hs
index 20105e8..cb4ba3e 100644
--- a/Control/Exception.hs
+++ b/Control/Exception.hs
@@ -116,9 +116,9 @@ module Control.Exception (
 import GHC.Base		( assert )
 import GHC.Exception 	as ExceptionBase hiding (catch)
 import GHC.Conc		( throwTo, ThreadId )
-import GHC.IOBase	( IO(..), IORef(..), newIORef, readIORef, writeIORef )
-import GHC.Handle       ( stdout, hFlush )
-import Foreign.C.String ( CString, withCStringLen )
+import Data.IORef	( IORef, newIORef, readIORef, writeIORef )
+import Foreign.C.String ( CString, withCString )
+import System.IO	( stdout, hFlush )
 #endif
 
 #ifdef __HUGS__
@@ -130,13 +130,6 @@ import System.IO.Error	hiding ( catch, try )
 import System.IO.Unsafe (unsafePerformIO)
 import Data.Dynamic
 
-#include "Typeable.h"
-INSTANCE_TYPEABLE0(Exception,exceptionTc,"Exception")
-INSTANCE_TYPEABLE0(IOException,ioExceptionTc,"IOException")
-INSTANCE_TYPEABLE0(ArithException,arithExceptionTc,"ArithException")
-INSTANCE_TYPEABLE0(ArrayException,arrayExceptionTc,"ArrayException")
-INSTANCE_TYPEABLE0(AsyncException,asyncExceptionTc,"AsyncException")
-
 -----------------------------------------------------------------------------
 -- Catching exceptions
 
@@ -169,13 +162,12 @@ INSTANCE_TYPEABLE0(AsyncException,asyncExceptionTc,"AsyncException")
 -- might be a 'ThreadKilled', for example).  In this case it is usually better
 -- to use 'catchJust' and select the kinds of exceptions to catch.
 --
--- Also note that The "Prelude" also exports a
--- function called 'catch' which has the same type as
--- 'Control.Exception.catch', the difference being that the
--- "Prelude" version only catches the IO and user
+-- Also note that the "Prelude" also exports a function called
+-- 'Prelude.catch' with a similar type to 'Control.Exception.catch',
+-- except that the "Prelude" version only catches the IO and user
 -- families of exceptions (as required by Haskell 98).  We recommend
 -- either hiding the "Prelude" version of
--- 'catch' when importing
+-- 'Prelude.catch' when importing
 -- "Control.Exception", or importing
 -- "Control.Exception" qualified, to avoid name-clashes.
 
@@ -220,25 +212,6 @@ handleJust :: (Exception -> Maybe b) -> (b -> IO a) -> IO a -> IO a
 handleJust p =  flip (catchJust p)
 
 -----------------------------------------------------------------------------
--- evaluate
-
--- | Forces its argument to be evaluated, and returns the result in
--- the 'IO' monad.  It can be used to order evaluation with respect to
--- other 'IO' operations; its semantics are given by
---
--- >   evaluate undefined `seq` return ()  ==> return ()
--- >   catch (evaluate undefined) (\e -> return ())  ==> return ()
---
--- NOTE: @(evaluate a)@ is /not/ the same as @(a \`seq\` return a)@.
-#ifdef __GLASGOW_HASKELL__
-evaluate :: a -> IO a
-evaluate a = IO $ \s -> case a `seq` () of () -> (# s, a #)
-	-- NB. can't write  
-	-- 	a `seq` (# s, a #)
-	-- because we can't have an unboxed tuple as a function argument
-#endif
-
------------------------------------------------------------------------------
 -- 'mapException'
 
 -- | This function maps one exception into another as proposed in the
@@ -254,7 +227,7 @@ mapException f v = unsafePerformIO (catch (evaluate v)
 -- 'try' and variations.
 
 -- | Similar to 'catch', but returns an 'Either' result which is
--- @(Right a)@ if no exception was raised, or @(Left e)@ if an
+-- @('Right' a)@ if no exception was raised, or @('Left' e)@ if an
 -- exception was raised and its value is @e@.
 --
 -- >  try a = catch (Right \`liftM\` a) (return . Left)
@@ -263,6 +236,11 @@ mapException f v = unsafePerformIO (catch (evaluate v)
 -- to re-throw the exception after performing whatever cleanup is needed.
 -- Otherwise, 'tryJust' is generally considered to be better.
 --
+-- Also note that "System.IO.Error" also exports a function called
+-- 'System.IO.Error.try' with a similar type to 'Control.Exception.try',
+-- except that it catches only the IO and user families of exceptions
+-- (as required by the Haskell 98 @IO@ module).
+
 try :: IO a -> IO (Either Exception a)
 try a = catch (a >>= \ v -> return (Right v)) (\e -> return (Left e))
 
@@ -489,23 +467,6 @@ Similar arguments apply for other interruptible operations like
 'System.IO.openFile'.
 -}
 
--- -----------------------------------------------------------------------------
--- Assert
-
-#ifdef __HADDOCK__
--- | If the first argument evaluates to 'True', then the result is the
--- second argument.  Otherwise an 'AssertionFailed' exception is raised,
--- containing a 'String' with the source file and line number of the
--- call to assert.
---
--- Assertions can normally be turned on or off with a compiler flag
--- (for GHC, assertions are normally on unless the @-fignore-asserts@
--- option is give).  When assertions are turned off, the first
--- argument to 'assert' is ignored, and the second argument is
--- returned as the result.
-assert :: Bool -> a -> a
-#endif
-
 #ifndef __GLASGOW_HASKELL__
 assert :: Bool -> a -> a
 assert True x = x
@@ -525,10 +486,11 @@ uncaughtExceptionHandler = unsafePerformIO (newIORef defaultHandler)
                Deadlock    -> "no threads to run:  infinite loop or deadlock?"
                ErrorCall s -> s
                other       -> showsPrec 0 other "\n"
-         withCStringLen ("Fail: "++msg) $ \(cstr,len) -> writeErrString cstr len
-         
-foreign import ccall unsafe "writeErrString__"
-	writeErrString :: CString -> Int -> IO ()
+         withCString "%s" $ \cfmt ->
+          withCString msg $ \cmsg ->
+            errorBelch cfmt cmsg
+
+foreign import ccall unsafe errorBelch :: CString -> CString -> IO ()
 
 setUncaughtExceptionHandler :: (Exception -> IO ()) -> IO ()
 setUncaughtExceptionHandler = writeIORef uncaughtExceptionHandler