On Thu, 2009-05-07 at 06:31 +0000, Antoine Pitrou wrote:
John Graham <john.a.graham@...> writes:
If the OP is asking for futures, couldn't that be implemented in a library without touching the language? It's a powerful enough feature to consider putting it in a library.
I don't know what C++ futures are but you should take a look at Twisted Deferred objects. The official implementation is in Python but a C implementation has been lingering on for years, you may be able to give them some help: http://twistedmatrix.com/trac/ticket/2245
Futures block, Defereds call forward. foo = something_returning_a_future() # does not block foo.get_value() # blocks def something_returning_a_future(): def worker(): [some code here that will does expensive work] return Future(worker) class Future: def __init__(callable): # imagine thread-safe code here to run callable in a thread def get_value(self): if not self.result: self.result = self.queue.pop() return self.result This is approximately a Future implementation for python. The difference - and its quite a big one - to Defereds is that defereds are a call-forward approach, whereas Futures are proxy objects that are waited on to get their results. twisted depends on never blocking as a core part of the design, Futures and Promises don't work well here. -Rob