how-do-i-have-a-global-state-in.hs

data ShellState = ShellState {
                    count :: Int
                  }




main = do
         ls <- getContents
         s <- return $ ShellState 0
         loop s $ lines ls

loop :: ShellState -> [String] -> IO ()
loop s [] = return ()
loop s (l:ls) = do
                  x <- executeCommand s l
                  putStrLn $ (show $ count $ fst x) ++ ", " ++ (snd x)
                  loop (fst x) ls

executeCommand :: ShellState -> String -> IO (ShellState, String)
executeCommand s line = return (ShellState $ 1 + count s, line)