I said: > In that case, we can treat subatomic as a "hint" to the STM runtime. It > could have a simpler type, and the semantics of "id": > > subatomic :: STM a -> STM a > > If the subatomic transaction turns out to be read-only, then we get the > benefit of all four cases Ryan describes above. If it turns out to be > read-write, we only get the benefit of cases 2 to 4, while case 1 must > restart. It doesn't matter if the subatomic transaction captures > variables which depend on previous reads, since changes to those reads > would cause a restart regardless of the outcome of the subatomic > transaction.
Scrap that. I realise now that it allows leakage of information read from variables. It would need to be: subatomic :: STM a -> STM () Which means it's no longer just a hint. _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe
