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Re: script uses up all memory

From Marko Rauhamaa <marko@pacujo.net>
Newsgroups comp.lang.python
Subject Re: script uses up all memory
Date 2014-03-07 01:53 +0200
Organization A noiseless patient Spider
Message-ID <878usmrijk.fsf@elektro.pacujo.net> (permalink)
References (4 earlier) <mailman.7879.1394144925.18130.python-list@python.org> <87ha7bq7ls.fsf@elektro.pacujo.net> <mailman.7880.1394145824.18130.python-list@python.org> <87d2hyrkf4.fsf@elektro.pacujo.net> <mailman.7881.1394148716.18130.python-list@python.org>

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Chris Angelico <rosuav@gmail.com>:

> Can you give a useful example of a closure that does create a refloop?

Just the other day, I mentioned the state pattern:

   class MyStateMachine:
       def __init__(self):
           sm = self

           class IDLE:
               def ding(self):
                   sm.open_door()
                   sm.state = AT_DOOR()

           class AT_DOOR:
               ...

           self.state = IDLE()

       def ding(self):
           self.state.ding()


So we have:

    MyStateMachine instance
      -> MyStateMachine instance.ding
         -> IDLE instance
            -> IDLE instance.ding
               -> MyStateMachine instance

plus numerous others in this example alone.

In general, event-driven programming produces circular references left
and right, and that might come into wider use with asyncio.

I suspect generators might create circular references as well.

Any tree data structure with parent references creates cycles.

In fact, I would imagine most OO designs create a pretty tight mesh of
back-and-forth references.


Marko

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Thread

Re: script uses up all memory Chris Angelico <rosuav@gmail.com> - 2014-03-07 09:28 +1100
  Re: script uses up all memory Marko Rauhamaa <marko@pacujo.net> - 2014-03-07 00:34 +0200
    Re: script uses up all memory Chris Angelico <rosuav@gmail.com> - 2014-03-07 09:43 +1100
      Re: script uses up all memory Marko Rauhamaa <marko@pacujo.net> - 2014-03-07 01:12 +0200
        Re: script uses up all memory Chris Angelico <rosuav@gmail.com> - 2014-03-07 10:31 +1100
          Re: script uses up all memory Marko Rauhamaa <marko@pacujo.net> - 2014-03-07 01:53 +0200
            Re: script uses up all memory Chris Angelico <rosuav@gmail.com> - 2014-03-07 11:11 +1100
              Re: script uses up all memory Marko Rauhamaa <marko@pacujo.net> - 2014-03-07 02:31 +0200

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