On 11:24 am, p.mayers@imperial.ac.uk wrote:

I only just noticed today that if a generator passed to a CooperativeTask does:

result = yield some_deferred()

...it doesn't work, because CooperativeTask doesn't .send() the result of the deferred bacn into the generator.

Is this intentional?

Yes. Cooperator is for iterators, not generators, making send unusable in the general case. Cooperator also isn't a replacement for inlineCallbacks. You can build a wrapper for a generator that works together with Cooperator and sends results back in. If it ends up being useful, it might be something to add to Twisted. Jean-Paul

If not, would that behaviour be desirable? It seems like it would be a useful pattern to me.

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On 02/11/11 12:39, Itamar Turner-Trauring wrote:

On Wed, 2011-11-02 at 11:24 +0000, Phil Mayers wrote:

...

I only just noticed today that if a generator passed to a CooperativeTask does:

result = yield some_deferred()

...it doesn't work, because CooperativeTask doesn't .send() the result of the deferred bacn into the generator.

Is this intentional? If not, would that behaviour be desirable? It seems like it would be a useful pattern to me.

Could you give an example snippet? I don't really understand the question, sorry.

I meant this: from twisted.internet import task, reactor, defer def dowork(n): d = defer.Deferred() result = 'waited %i' % (n,) reactor.callLater(n, d.callback, result) return d def work(): for i in (1,2,3): rv = yield dowork(i) print rv task.coiterate(work()) reactor.run() ...prints: None None None rather than waited 1 waited 2 waited 3 i.e. the iterator that is yielding deferreds doesn't "see" the results emerge from the "yield" in the same way inlineCallbacks do. Obviously it's pretty trivial to get at the results: holder = {} def cb(r): holder['result'] = r return r yield dowork(i).addCallback(cb) print holder['result'] But the essential point I was missing is that Cooperator is for general purpose iterators, not just generators.