FibbSlow.hs

module Main where

import Prelude
import System.Environment

fibb_slow :: Integer -> Integer
fibb_slow 1 = 1
fibb_slow 2 = 1
fibb_slow x = fibb_slow (x-1) + fibb_slow (x-2)


main :: IO ()
main = do
  args <- getArgs
  if length args < 1
  then
    putStrLn "Usage fibb_hs <number>"
  else do
    let num = read $ head args :: Integer
--  putStrLn $ show __GLASGOW_HASKELL__
    putStrLn $ "Haskell says: " ++ show (fibb_slow num)