Hi Chris. I don't think that version could type-check. Try it out. - Conal On Dec 3, 2007 8:52 AM, Chris Kuklewicz wrote:

In State, the tuple order that is use is

...

newtype State s a = State { runState :: (s -> (a, s)) }

So I would expect you to use the same order for writer. This only changes (>>) below:

...

instance Monoid o => Monad ((,) o) where return = (a,mempty) (a,o) >>= f = (a',o `mappend` o') where (a',o') = f a

-- Chris