On Apr 27, 2008, at 10:05 AM, Jake Mcarthur wrote:
On Apr 27, 2008, at 9:36 AM, Conal Elliott wrote:
I think we *do* want unsafeNewEmptyTMVar inlined. Here's a convenient caching wrapper:
cached :: STM a -> TIVal a cached m = TIVal m (unsafePerformIO newEmptyTMVarIO)
Yes, this is essentially what I am working with in Reaction at the moment.
Actually, that is not quite what I have been doing. Here is what I had: cachedFuture :: STM (a, Time) -> Future a cachedFuture stm = unsafePerformIO $ return . Future stm =<< newEmptyTMVarIO {-# NOINLINE cachedFuture #-} (Clearly I am skipping right past an implementation of TIVals, despite the fact that they may be useful as a separate abstraction. This is just laziness.) If I replace the above with... cachedFuture :: STM (a, Time) -> Future a cachedFuture stm = Future stm (unsafePerformIO newEmptyTMVarIO) then my test program hangs, with or without the NOINLINE pragma. I can't guess why because, like I already said, I haven't yet thought all the way through the relationship between unsafePerformIO and NOINLINE. - Jake