[Haskell-cafe] Tricky exception handling

[Joel Reymont]

Folks,

I have a thread that launches socket reader and writer threads. My  
intent is to notify the main thread when an exception is caught by  
the reader/writer. Is this code proper?

---
withException :: (Event a -> IO ())
                  -> IO ()
                  -> IO Bool
withException post action =
     handle (\e -> do case e of
                        AsyncException ThreadKilled -> return ()
                        _ -> post $ NetworkError e
                      return False
            ) $ do { action; return True }

writeLoop :: (Event a -> IO ()) -> Handle -> (SSL, BIO, BIO) -> IO ()
writeLoop post h ssl =
     do go <- withException post $
              do cmd <- read h ssl
                 post $! Cmd $! cmd
        when go $ writeLoop post h ssl
---

	Thanks, Joel

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