wc :: A.Args -> IO ()
wc args = case A.files0from args of
               Just f   -> files0from f >>= doFiles args
               Nothing  -> case A.files args of
                                Nothing -> doStdin args
                                Just fs -> doFiles args fs
wc :: A.Args -> IO ()
wc args = case A.files0from args of
               Just f   -> files0from f >>= doFiles args
               Nothing  -> case A.files args of
                                Nothing -> doStdin args
                                Just fs -> doFiles args fs
wc args = case A.files0from args of
               Just f   -> files0from f >>= doFiles args
               Nothing  -> case A.files args of
                                Nothing -> doStdin args
                                Just fs -> doFiles args fs