\begin{code}
import IO
findM f [] = return Nothing
findM f (x:xs) = do { b <- f x; if b then return (Just x) else findM f xs }
isLeft (Left _) = True
isLeft _ = False
main =
findM (>>=return.isLeft) $
map (try . uncurry (>>=)) $
zip (hGetCharS stdin) (hPutCharS stdout)
where
hGetCharS h = hGetChar h : hGetCharS h
hPutCharS h = hPutChar h : hPutCharS h
\end{code}
Joining input list and output list by uncurried >>=
IO errors such as EOF are enclosed by try.
findM finds those EOF or IO errors.
_______________________________________________
Haskell-Cafe mailing list
[EMAIL PROTECTED]
http://www.haskell.org/mailman/listinfo/haskell-cafe
