-tryMost :: IO a -> IO (Either Exception.Exception a)
-tryMost action = do r <- try action; filter r
- where
- filter (Left e@(Exception.DynException d))
- | Just ghc_ex <- fromDynamic d
- = case ghc_ex of
- Interrupted -> Exception.throw e
- Panic _ -> Exception.throw e
- _other -> return (Left e)
- filter other
- = return other
-
--- | tryUser is like try, but catches only UserErrors.
--- These are the ones that are thrown by the TcRn monad
--- to signal an error in the program being compiled
-tryUser :: IO a -> IO (Either Exception.Exception a)
-tryUser action = tryJust tc_errors action
- where
- tc_errors e@(Exception.IOException ioe) | isUserError ioe = Just e
- tc_errors _other = Nothing
-\end{code}
+-- XXX I'm not entirely sure if this is catching what we really want to catch
+tryMost :: IO a -> IO (Either SomeException a)
+tryMost action = do r <- try action
+ case r of
+ Left se ->
+ case fromException se of
+ -- Some GhcException's we rethrow,
+ Just (Signal _) -> throwIO se
+ Just (Panic _) -> throwIO se
+ -- others we return
+ Just _ -> return (Left se)
+ Nothing ->
+ case fromException se of
+ -- All IOExceptions are returned
+ Just (_ :: IOException) ->
+ return (Left se)
+ -- Anything else is rethrown
+ Nothing -> throwIO se
+ Right v -> return (Right v)
+\end{code}