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.

On 02/11/11 13:08, exarkun@twistedmatrix.com wrote:

Yes. Cooperator is for iterators, not generators, making send unusable

Ah of course.

in the general case. Cooperator also isn't a replacement for inlineCallbacks.

That was essentially my question ;o)