import Random

-- generate random input files of various sizes for the additive parser


generateRandom :: Int -> IO String
generateRandom x = ans x >>= return . ($ []) where
    ans x = do
        r <- randomIO
        case abs r `mod` 7 :: Int of
            1 -> do
                s <- ans x
                return (showString "(" . s . showString ")")
            2 -> do
                s1 <- ans (x - 1)
                s2 <- ans (x - 1)
                return (s1 . showString "*" . s2)
            3 -> do
                s1 <- ans (x - 1)
                s2 <- ans (x - 1)
                return (s1 . showString "+" . s2)
            _ | x < 0 -> do
                n <- randomIO
                return (shows (n `mod` 256::Int))
            _ -> ans x

main = do
    flip mapM_ [2 .. 15] $ \x -> do
        s <- generateRandom x
        let fn = "test" ++ show x ++ ".txt"
        putStrLn $ "Writing '" ++ fn ++ "'"
        writeFile fn s