[project @ 2003-04-01 16:30:37 by simonpj]

[ghc-base.git] / GHC / Exception.lhs

diff --git a/GHC/Exception.lhs b/GHC/Exception.lhs
index 5822ea8..a98ca19 100644 (file)
--- a/GHC/Exception.lhs
+++ b/GHC/Exception.lhs
@@ -14,20 +14,15 @@
 -- 
 -----------------------------------------------------------------------------
 
-#ifndef __HUGS__
 module GHC.Exception 
        ( module GHC.Exception, 
          Exception(..), AsyncException(..), 
          IOException(..), ArithException(..), ArrayException(..),
-         throw, ioError ) 
+         throw, throwIO, ioError ) 
   where
 
-import Data.Either
-
 import GHC.Base
 import GHC.IOBase
-
-#endif
 \end{code}
 
 %*********************************************************
@@ -50,60 +45,17 @@ have to work around that in the definition of catchException below).
 
 \begin{code}
 catchException :: IO a -> (Exception -> IO a) -> IO a
-#ifdef __HUGS__
-catchException m k =  ST (\s -> unST m s `primCatch'` \ err -> unST (k err) s)
-#else
 catchException (IO m) k =  IO $ \s -> catch# m (\ex -> unIO (k ex)) s
-#endif
 
-catch           :: IO a -> (Exception -> IO a) -> IO a 
+catch           :: IO a -> (IOError -> IO a) -> IO a 
 catch m k      =  catchException m handler
-  where handler err@(IOException _) = k err
+  where handler (IOException err)   = k err
        handler other               = throw other
 \end{code}
 
 
 %*********************************************************
 %*                                                     *
-\subsection{Try and bracket}
-%*                                                     *
-%*********************************************************
-
-The construct @try comp@ exposes errors which occur within a
-computation, and which are not fully handled.  It always succeeds.
-
-These are the IO-only try/bracket.  For the full exception try/bracket
-see hslibs/lang/Exception.lhs.
-
-\begin{code}
-try            :: IO a -> IO (Either Exception a)
-try f          =  catch (do r <- f
-                            return (Right r))
-                        (return . Left)
-
-bracket        :: IO a -> (a -> IO b) -> (a -> IO c) -> IO c
-bracket before after m = do
-        x  <- before
-        rs <- try (m x)
-        after x
-        case rs of
-           Right r -> return r
-           Left  e -> ioError e
-
--- variant of the above where middle computation doesn't want x
-bracket_        :: IO a -> (a -> IO b) -> IO c -> IO c
-bracket_ before after m = do
-         x  <- before
-         rs <- try m
-         after x
-         case rs of
-            Right r -> return r
-            Left  e -> ioError e
-\end{code}
-
-
-%*********************************************************
-%*                                                     *
 \subsection{Controlling asynchronous exception delivery}
 %*                                                     *
 %*********************************************************
@@ -126,13 +78,8 @@ block :: IO a -> IO a
 -- be disabled again.
 unblock :: IO a -> IO a
 
-#ifndef __HUGS__
 block (IO io) = IO $ blockAsyncExceptions# io
 unblock (IO io) = IO $ unblockAsyncExceptions# io
-#else
-unblock :: IO a -> IO a
-unblock (IO io) = IO io
-#endif
 \end{code}