> The previous "newtype Labeller a = Labeller (Int -> (Int, a))" (the
> result tuple is reversed within Control.Monad.State) would simply become
> (untested):
>
> newtype Labeller a = State Int a
>
> newLabel = do { n <- get; put (n + 1); return (Label n) }
>
> runLabeller l = execState l minBound
it must be "evalState" instead of "execState"