[Python-ideas] Revised**12 PEP on Yield-From

Erik Groeneveld erik at cq2.org
Fri Apr 24 13:27:30 CEST 2009


2009/4/24 Greg Ewing <greg.ewing at canterbury.ac.nz>:
> Seems to me you could yield a sequence of values
> to be pushed back, and use a top-level driver
> something like this:
>  def pushingback(g):
>    queue = []
>    try:
>      while 1:
>        queue.append(yield)
>        while queue:
>          pushback = g.send(queue.pop(0))
>          if pushback:
>            queue.extend(pushback)
>    except StopIteration, e:
>      return e.value

Great.  I think this is gonna work as a top level driver and I'll work
it out. Thanks!

> So when seeing the generator send/yield mechanism for
> the first time, it's tempting to think of it as being
> like sending data to a process through a pipe. But
> it's not really like that -- it's a lower-level
> facility.

I regret I apparently didn't raise your interest in mapping JSP onto
Python coroutines. If you ever get sick of queues, buffers and
callbacks, give it a try!

Thanks so far, I look forward to the definite implementation of your PEP.


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