Thanks, Ryan, for the reminder and explanation of this problem. - Conal On Mon, Apr 28, 2008 at 8:01 PM, Ryan Ingram <[EMAIL PROTECTED]> wrote:
> The problem I have with all of these STM-based solutions to this > problem is that they don't actually cache until the action fully > executes successfully. > > For example, if you have a :: TIVal a, and f :: a -> TIVal b, and you > execute > force (a >>= f) > > and the action returned by f executes retry for whatever reason, then > the caching done in "a" gets undone. Ideally I want to be able to > provide some proof that the result of a is pure and have it committed > immediately when it finishes. > > Every attempt I've had so far to solve this problem ends up being some > type of the form > newtype X a = IO (STM (Either a (X a))) > which has its own problems. > > -- ryan >
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