Excerpts from Heka Treep's message of Mon Jan 23 15:11:51 -0500 2012: > -------------------------------------------------------------------------------- > import Control.Monad.STM > import Control.Concurrent > import Control.Concurrent.STM.TChan > > spawn f = do > mbox <- newTChanIO > forkIO $ f mbox > return mbox > > (!) = writeTChan > > actor mbox = do > empty <- atomically $ isEmptyTChan mbox > if empty > then actor mbox > else do > val <- atomically $ readTChan mbox
Uh, don't you want to combine isEmptyChan and readTChan into one single atomic action? > putStrLn val > actor mbox > > test = do > mbox <- spawn actor > atomically $ mbox ! "1" > atomically $ mbox ! "2" > atomically $ mbox ! "3" > > -- > test > -- 1 > -- 2 > -- 3 > -------------------------------------------------------------------------------- > > But there are several problems: > > * The @actor@ function is busy checking the channel all the time. GHC's runtime system is clever. It will block appropriately. > * Caller and callee need to perform synchronizations (for the @Chan@) > or atomically transactions (for the @TChan@). The synchronization for Chan is very cheap, and you would have needed to synchronize anyway in Erlang (Erlang message queues are not lock free!) Cheers, Edward _______________________________________________ Glasgow-haskell-users mailing list Glasgow-haskell-users@haskell.org http://www.haskell.org/mailman/listinfo/glasgow-haskell-users
