On Jan 19, 2010, at 1:10 PM, Simon Brunning wrote:
2010/1/19 cool-RR <cool-rr@cool-rr.com>:
Is there a reason that queues don't have an `__iter__` method? I mean both `Queue.Queue` and `multiprocessing.Queue`.
Could it be made threadsafe?
To me, this is exactly the right line of questioning. Is there a use case for iterating through a queue that is being mutated by consumers and producers? If so, should the consumers and producers be locked out during iteration or should the iterator fail if it detects a mutation (like we currently do for dictionaries that change during iteration). The semantics should be dictated by use cases. When someone writes "for t in q: action(q)" what is the most useful thing to happen when another thread does a get or put? My personal opinion is that queues are better-off without an iterator. They serve mainly to buffer consumers and producers and iteration does fit in well. In other words, adding __iter__ to queues in threaded environment may do more harm than good. Raymond