As someone mentioned, don't worry about being new to Haskell, but DO send your messages to haskell-cafe@haskell.org, not the main Haskell list. I'm redirecting this so that the Helpful Denizens of the Haskell Cafe can help you. Simon | -----Original Message----- | From: haskell-bounces@haskell.org [mailto:haskell-bounces@haskell.org] On Behalf Of Duong Thai Ha | Sent: 06 May 2007 17:03 | To: haskell@haskell.org | Subject: [Haskell] Monad and Monad transformer??? | | hi | I am a newbee to haskell so please forgive me if the question is not | appropreate. | | I am trying to get the idea of using Monad and have to understand the | following code. | | Can you please tell me is how different Monad and Monad transformer is? | And what is mean by | | > newtype State s a = State { runState :: s -> (a, s) } | | --------------------------------- | | Define (State s) as a State monad | | > instance Monad (State s) where | > return a = State $ \s -> (a,s) | > m >>= k = State $ \s -> let (a,s') = runState m s in runState (k | a) s' | | Thanks lot for your help | I really do appreciate that | | Best regard | _______________________________________________ | Haskell mailing list | Haskell@haskell.org | http://www.haskell.org/mailman/listinfo/haskell