Hi Tom, you can do this with Twilight STM. I recently uploaded the first version on hackage[1]. The next version including a better algorithm and examples is about to be released in a few days. Twilight STM features include tagging of variables and fine-grained conflict detection, flexible isolation level semantics (snapshot isolation and opacity) as well as safe integration of I/O. - Annette [1] http://hackage.haskell.org/package/twilight-stm Am 28.09.2010 15:35, schrieb Tom Hawkins:
Has anyone in the STM community considered the ability to read a TVar, such that it would allow the transaction to complete even if the TVar was modified by another transaction? (I am assuming this is not how STM works by default.) For example:
looselyReadTVar :: TVar a -> STM a
Atom [1] has similar semantics to STM. If Atom were to relax it's rule atomicity in this fashion, it could open the door to improved task scheduling and higher levels of program description. Has STM research already gone down this path?
-Tom
[1] http://hackage.haskell.org/package/atom _______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe