On Thu, Apr 1, 2010 at 8:20 PM, Jason J. W. Williams <jasonjwwilli...@gmail.com> wrote: > Would it be fair to say that when developing code that utilizes > inlineCallbacks, your function is a generator that returns a deferred > whose callback is the coroutine that's yielding?
It pays to be very very specific about all the different objects and interactions going on with generators in Python and especially with inlineCallbacks to avoid confusion.There are a couple of inaccuracies in this statement, some which I think are just about poor wording and some which come from misunderstanding. In Python, there are generator functions and there are generators. Calling a generator function returns a generator, which has next() and send() methods. Generators do not return things, though a generator's next() or send() methods do (I say this because you mentioned a "generator that returns a deferred"). Also, there's nothing called a "coroutine" that's related to inlineCallbacks at all, and the word is fraught with ambiguities in Python, so it's best to just avoid it entirely. In inlineCallbacks, nobody but the person writing the inlineCallbacks-using function knows that there's a generator involved. The person calling your inlineCallbacks-using function can't see any generators; they just get a Deferred object which fires when the generator is exhausted. The interesting part is that inlineCallbacks is the thing responsible for iterating the generator, not user-code. It is responsible for calling .send() on the generator object when previously yielded deferreds have fired. The value of the Deferred returned will be whatever is passed to returnValue in the inlineCallbacks-using function. -- Christopher Armstrong http://radix.twistedmatrix.com/ http://planet-if.com/ _______________________________________________ Twisted-Python mailing list Twisted-Python@twistedmatrix.com http://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
