Re: [Haskell-cafe] MonadMemory class

Hi Ariel J. Birnbaum wrote:

Two questions came to mind while thinking of memory references in Haskell:

1. Is there a "standard" equivalent of the following:

class (Monad m) => MonadMemory m r | m -> r where new :: a -> m (r a) read :: r a -> m a write :: r a -> a -> m ()

I do not think you can call it standard, but TypeCompose http://hackage.haskell.org/cgi-bin/hackage-scripts/package/TypeCompose-0.5 do implement Data.RefMonad, which does what you are describing. Greetings, Mads Lindstrøm

What kind of axioms should an instance of this class satisfy?

2. How would a "pure" instance of this class look like (obvious unsafePerformIO-based solutions aside)? Is it even possible in pure Haskell?

Thanks much!