import System.Environment
import System.IO.Error
data Parameters = Parameters String String [Int]

main :: IO ()
main = getArgs
   >>= processArgs
   >>= either putStrLn doRealWork

processArgs :: [String] -> IO (Either String Parameters)
processArgs args = (return $ enumerateArgs args)
               >>= (either (return . Left) parseArgs)
                -- This maybe could be improved, but it's not the focus

doRealWork     :: Parameters -> IO ()
doRealWork     = undefined -- I'll implement the real work part later

enumerateArgs  :: [String] -> Either String (String,String,String)
enumerateArgs list
  | length list == 3 = Right (a,b,c)
  | otherwise        = Left $ "Incorrect Argument Count,n"
                          ++  "Expected 3 parametersn"
                          ++  "Received: " ++ show list
  where (a:b:c:[]) = list

readFileEither :: String -> IO (Either String String)
readFileEither = undefined -- it actually works, implementation is irrelevant

parseArgs'     :: String -> String -> String -> Either String Parameters
parseArgs'     = undefined -- it actually works, implementation is irrelevant

parseArgs :: (String,String,String) -> IO (Either String Parameters)
parseArgs (a,b,c) = readFileEither c >>= (x -> return . (x >>= (parseArgs' a b)))
                          -- IO bind ^^^        Either bind ^^^

Couldn't match expected type `IO (Either String Parameters)'
            with actual type `a0 -> c0'
In the expression: return . (x >>= (parseArgs' a b))
In the second argument of `(>>=)', namely
  `( x -> return . (x >>= (parseArgs' a b)))'
In the expression:
  readFileEither c >>= ( x -> return . (x >>= (parseArgs' a b)))

instance Monad (Either e) where
    return = Right
    Left  l >>= _ = Left l
    Right r >>= k = k r