Re: [Haskell-cafe] Relaxing atomicity of STM transactions

On Sep 28, 2010, at 6:36 PM, Tom Hawkins wrote: Thanks for the responses, but I think I should explain a bit more. I'm not interested in being able to read the live value of a TVar at any arbitrary time (via. unsafeIOToSTM). But rather I would like looslyReadTVar to have exactly the same semantics as readTVar, except that the STM runtime would not reject the transaction if the TVar is modified by another transaction before the atomic commit takes place. Given the current implementation, I think the easiest way to get those semantics is to lift the untracked readTVarIO into STM with unsafeIOToSTM.