At 2002-02-05 16:54, I wrote:
> data Ref m a = MkRef
> {
> get :: m a,
> set :: a -> m (),
> modify :: (a -> a) -> m ()
> };
Better,
data Ref m a = MkRef
{
get :: m a,
set :: a -> m ()
};
modify :: (Monad m) => Ref m a -> (a -> a) -> m ();
modify ref map = (get ref) >>= ((set ref) . map);
--
Ashley Yakeley, Seattle WA
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