On Feb 22, 2015, at 7:52 AM, Laura Creighton <l...@openend.se> wrote:
> In a message of Sun, 22 Feb 2015 07:16:14 -0500, Cem Karan writes: > >> This was PRECISELY the situation I was thinking about. My hope was >> to make the callback mechanism slightly less surprising by allowing >> the user to track them, releasing them when they aren't needed >> without having to figure out where the callbacks were registered. >> However, it appears I'm making things more surprising rather than >> less. > > You may be able to accomplish your goal by using a Queue with a > producer/consumer model. > see: > http://stackoverflow.com/questions/9968592/turn-functions-with-a-callback-into-python-generators > > especially the bottom of that. > > I haven't run the code, but it looks mostly reasonable, except that > you do not want to rely on the Queue maxsize being 1 here, and > indeed, I almost always want a bigger Queue in any case. Use > Queue.task_done if blocking the producer features in your design. > > The problem that you are up against is that callbacks are inherantly > confusing, even to programmers who are learning about them for the > first time. They don't fit people's internal model of 'how code works'. > There isn't a whole lot one can do about that except to > try to make the magic do as little as possible, so that more of the > code works 'the way people expect'. I think what you're suggesting is that library users register a Queue instead of a callback, correct? The problem is that I'll then have a strong reference to the Queue, which means I'll be pumping events into it after the user code has gone away. I was hoping to solve the problem of forgotten registrations in the library. Thanks, Cem Karan -- https://mail.python.org/mailman/listinfo/python-list
