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Groups > comp.lang.python > #27332

Re: set and dict iteration

Newsgroups comp.lang.python
Date 2012-08-18 13:29 -0700
References (2 earlier) <7xy5le7cli.fsf@ruckus.brouhaha.com> <mailman.3404.1345158704.4697.python-list@python.org> <502dab6c$0$29978$c3e8da3$5496439d@news.astraweb.com> <fe95c29c-2289-4e9c-870e-e3c475f13459@googlegroups.com> <mailman.3435.1345240665.4697.python-list@python.org>
Subject Re: set and dict iteration
From Aaron Brady <castironpi@gmail.com>
Message-ID <mailman.3473.1345321756.4697.python-list@python.org> (permalink)

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On Friday, August 17, 2012 4:57:41 PM UTC-5, Chris Angelico wrote:
> On Sat, Aug 18, 2012 at 4:37 AM, Aaron Brady <castironpi@gmail.com> wrote:
> 
> > Is there a problem with hacking on the Beta?
> 
> 
> 
> Nope. Hack on the beta, then when the release arrives, rebase your
> 
> work onto it. I doubt that anything of this nature will be changed
> 
> between now and then.
> 
> 
> 
> ChrisA

Thanks Chris, your post was encouraging.

I have a question about involving the 'tp_clear' field of the types.

http://docs.python.org/dev/c-api/typeobj.html#PyTypeObject.tp_clear

'''
...The tuple type does not implement a tp_clear function, because it’s possible to prove that no reference cycle can be composed entirely of tuples. 
'''

I didn't follow the reasoning in the proof; the premise is necessary but IMHO not obviously sufficient.  Nevertheless, the earlier diagram contains an overt homogeneous reference cycle.

Reposting: http://home.comcast.net/~castironpi-misc/clpy-0062%20set%20iterators.png

In my estimate, the 'tp_traverse' and 'tp_clear' fields of the set doesn't need to visit the auxiliary collection; the same fields of the iterators don't need to visit the primary set or other iterators; and references in the linked list don't need to be included in the iterators' reference counts.

Can someone who is more familiar with the cycle detector and cycle breaker, help prove or disprove the above?

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set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-08-16 11:00 -0700
  Re: set and dict iteration Dave Angel <d@davea.name> - 2012-08-16 15:49 -0400
    Re: set and dict iteration Paul Rubin <no.email@nospam.invalid> - 2012-08-16 14:26 -0700
      Re: set and dict iteration Dave Angel <davea@dejaviewphoto.com> - 2012-08-16 19:11 -0400
        Re: set and dict iteration Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-17 02:24 +0000
          Re: set and dict iteration Paul Rubin <no.email@nospam.invalid> - 2012-08-16 19:30 -0700
            Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-08-17 11:11 -0700
          Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-08-17 11:37 -0700
            Re: set and dict iteration Chris Angelico <rosuav@gmail.com> - 2012-08-18 07:57 +1000
              Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-08-18 13:29 -0700
              Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-08-18 13:29 -0700
                Re: set and dict iteration MRAB <python@mrabarnett.plus.com> - 2012-08-18 23:14 +0100
                Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-08-18 19:28 -0700
                Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-08-23 09:49 -0700
                Re: set and dict iteration Ian Kelly <ian.g.kelly@gmail.com> - 2012-08-27 13:17 -0600
                Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-09-02 10:43 -0700
                Re: set and dict iteration Ian Kelly <ian.g.kelly@gmail.com> - 2012-09-03 13:29 -0600
                Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-09-03 13:04 -0700
                Re: set and dict iteration Dave Angel <d@davea.name> - 2012-09-03 16:27 -0400
                Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-09-03 17:24 -0700
                Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-09-03 17:24 -0700
                Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-09-03 13:04 -0700
                Re: set and dict iteration Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-09-04 01:26 +0000
                Re: set and dict iteration Dave Angel <d@davea.name> - 2012-09-03 21:50 -0400
                Re: set and dict iteration Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-09-04 01:59 +0000
                Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-09-08 08:42 -0700
                Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-09-02 10:43 -0700
                Re: set and dict iteration Serhiy Storchaka <storchaka@gmail.com> - 2012-09-04 00:46 +0300
                Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-08-23 09:49 -0700
                Re: set and dict iteration Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2012-08-23 18:11 +0000
                Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-08-27 11:10 -0700
                Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-09-08 15:07 -0700
                Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-08-18 19:28 -0700
                Re: set and dict iteration Thomas Rachel <nutznetz-0c1b6768-bfa9-48d5-a470-7603bd3aa915@spamschutz.glglgl.de> - 2012-09-08 22:06 +0200
                Re: set and dict iteration Hans Mulder <hansmu@xs4all.nl> - 2012-09-08 23:18 +0200
                Re: set and dict iteration MRAB <python@mrabarnett.plus.com> - 2012-09-08 22:22 +0100
      Re: set and dict iteration Ian Kelly <ian.g.kelly@gmail.com> - 2012-08-16 17:43 -0600
        Re: set and dict iteration Paul Rubin <no.email@nospam.invalid> - 2012-08-16 18:01 -0700
          Re: set and dict iteration Ulrich Eckhardt <ulrich.eckhardt@dominolaser.com> - 2012-08-17 13:16 +0200
          Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-08-17 11:03 -0700
          Re: set and dict iteration 88888 Dihedral <dihedral88888@googlemail.com> - 2012-09-10 13:14 -0700
  Re: set and dict iteration Ian Kelly <ian.g.kelly@gmail.com> - 2012-08-16 16:55 -0600
  Re: set and dict iteration Ian Kelly <ian.g.kelly@gmail.com> - 2012-08-16 17:07 -0600
    Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-08-17 10:47 -0700
    Re: set and dict iteration Aaron Brady <castironpi@gmail.com> - 2012-08-17 10:47 -0700

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