I don't understand generator.send()

[Ian Kelly]

On Sat, May 14, 2011 at 7:17 PM, Chris Angelico <rosuav at gmail.com> wrote:
> You're right. It needs a while loop instead of the if (and some slight
> reordering):
>
> def ints():
>   i=0
>   queue=[]
>   while True:
>       if queue:  # see other thread, this IS legal and pythonic and
> quite sensible
>           sent=(yield queue.pop(0))
>       else:
>           sent=(yield i)
>           i+=1
>       while sent is not None:
>           queue.append(sent)
>           sent=(yield None)  # This is the return value from gen.send()
>
> That should work.

Yeah, that should do it.  But this is so much easier to get right and
to understand:

import itertools

class Ints(object):

    def __init__(self):
        self.ints = itertools.count()
        self.queue = []

    def __iter__(self):
        return self

    def next(self):
        if self.queue:
            return self.queue.pop(0)
        else:
            return self.ints.next()

    def insert(self, x):
        self.queue.append(x)