Some funky command line parsing of stuffs

app/Main.hs

@@ -1,29 +1,39 @@
 module Main where
 
 import Control.Monad
+import Data.Functor
 import System.Environment
 import System.Exit
 import Text.ParserCombinators.ReadP
 
+
+
 parse :: ReadP String -> String -> String
 parse rules = fst . last .readP_to_S rules
 
 main :: IO ()
-main = useArgs =<< ( parse argParse . unlines) <$> getArgs
+main = putStrLn =<< helper =<< getArgs
+
+helper :: [String] -> IO String
+helper []       = return usage
+helper (x:[])   = if (head x /= '-')
+                    then readFile x
+                    else return $ useArgs $ parse argParse x
+helper (x:_:[]) = return $ useArgs $ parse argParse x
+helper _        = fail "Too many arugemnts"
+
 
 argParse :: ReadP String
 argParse =
   string "-" >> (many1 (satisfy (/= ' ')))
 
-useArgs :: String -> IO a
+useArgs :: String -> String
-useArgs []       = exit
+useArgs []       = ""
-useArgs ('h':_) = usage   >> exit
+useArgs ('h':_)  = usage
-useArgs ('v':_) = version >> exit
+useArgs ('v':_)  = version
 useArgs (_:xs)   = useArgs xs
 
-usage :: IO ()
+usage :: String
-usage   = putStrLn "Usage: otm [-hv] [file]"
+usage   = "Usage: otm [-hv] [file]"
-version :: IO ()
+version :: String
-version = putStrLn "otm 0.1"
+version = "otm 0.1"
-exit :: IO a
-exit    = exitWith ExitSuccess