weidagang · March 2, 2017 02:29
diff --git a/ioref.hs b/ioref.hs
 import Data.IORef

 main :: IO ()
 main = do
  putStrLn "Create a mutable state 0."
  ref <- newIORef (0 :: Int)
  putStrLn "Increase by 1."
  modifyIORef ref (+1)
  result <- readIORef ref
  print result
	import Data.IORef

	main :: IO ()
	main = do
	putStrLn "Create a mutable state 0."
	ref <- newIORef (0 :: Int)
	putStrLn "Increase by 1."
	modifyIORef ref (+1)
	result <- readIORef ref
	print result