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Groups > comp.lang.python > #67799

Re: Reference

From Ben Finney <ben+python@benfinney.id.au>
Subject Re: Reference
Date 2014-03-05 15:32 +1100
References (7 earlier) <53155c15$0$2923$c3e8da3$76491128@news.astraweb.com> <mailman.7693.1393910647.18130.python-list@python.org> <op.xb75g7ap5079vu@gnudebeest> <roy-A9E76C.21091704032014@news.panix.com> <164d209c-ba5e-449f-bc25-c27ebfb1fc0f@googlegroups.com>
Newsgroups comp.lang.python
Message-ID <mailman.7791.1393993951.18130.python-list@python.org> (permalink)

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Rustom Mody <rustompmody@gmail.com> writes:

> * ... which summarizes my objection in this thread:

Your long post references many things. Which is the “which” to which you
refer? What is it you're referring to that summarises your position?

> Python's 'is' leaks the machine abstraction.

No, it does not. The ‘is’ operator compares object identity, which is
itself an abstraction. What is leaking?

Note that the “location of the object in memory” is not a guarantee made
by either Python's object identity nor the ‘id’ function. There's no
need to treat “object location in memory” as equal to “object identity”,
and code which makes that assumption is buggy. The documentation doesn't
promise they will be the same.

So, the fact that some Python implementations happen to present
‘id(foo)’ values that coincide with a representation of memory location,
does not constitute a leaky abstraction: there is no need for any Python
programmer to care about what the memory location is. So if that's the
basis of your objection, I don't consider that objection to be
legitimate.

> 'id' does it legitimately (somewhat), 'is' does it illegitimately

What would, in your view, be a legitimate way for Python to present
object identity to the programmer? How would it differ substantially
from Python's existing abstraction of object identity?

-- 
 \          “That's all very good in practice, but how does it work in |
  `\                                             *theory*?” —anonymous |
_o__)                                                                  |
Ben Finney

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Thread

Reference "ast" <nomail@invalid.com> - 2014-03-03 10:42 +0100
  Object identity (was: Reference) Ben Finney <ben+python@benfinney.id.au> - 2014-03-03 21:00 +1100
    Re: Object identity (was: Reference) "ast" <nomail@invalid.com> - 2014-03-03 11:21 +0100
  Re: Reference "Mark H. Harris" <harrismh777@gmail.com> - 2014-03-03 05:09 -0800
  Re: Reference Grant Edwards <invalid@invalid.invalid> - 2014-03-03 14:29 +0000
  Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-03 07:52 -0800
    Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-04 08:10 +1100
    Re: Reference Tim Chase <python.list@tim.thechases.com> - 2014-03-03 15:24 -0600
    Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-04 08:31 +1100
    Re: Reference Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-03 21:35 +0000
      Re: Reference Marko Rauhamaa <marko@pacujo.net> - 2014-03-04 00:07 +0200
        Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-04 09:18 +1100
          Re: Reference Alister <alister.ware@ntlworld.com> - 2014-03-04 11:10 +0000
            Re: Reference Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-04 11:48 +0000
              Re: Reference "Rhodri James" <rhodri@wildebst.org.uk> - 2014-03-05 00:25 +0000
    Re: Reference Tim Chase <python.list@tim.thechases.com> - 2014-03-03 15:51 -0600
    Re: Reference Jerry Hill <malaclypse2@gmail.com> - 2014-03-03 17:02 -0500
      Re: Reference Marko Rauhamaa <marko@pacujo.net> - 2014-03-04 00:22 +0200
        Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-04 09:27 +1100
        Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-04 09:33 +1100
        Re: Reference Steven D'Aprano <steve@pearwood.info> - 2014-03-04 04:52 +0000
          Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-04 16:24 +1100
            Re: Reference "Rhodri James" <rhodri@wildebst.org.uk> - 2014-03-05 01:08 +0000
              Re: Reference Roy Smith <roy@panix.com> - 2014-03-04 21:09 -0500
                Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-04 19:36 -0800
                Re: Reference Ian Kelly <ian.g.kelly@gmail.com> - 2014-03-04 21:08 -0700
                Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-04 20:31 -0800
                Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-05 15:32 +1100
                Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-04 20:47 -0800
                Re: Reference Steven D'Aprano <steve@pearwood.info> - 2014-03-05 05:06 +0000
                Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-04 21:47 -0800
                Re: Reference alex23 <wuwei23@gmail.com> - 2014-03-05 16:01 +1000
                Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-04 22:10 -0800
                Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-05 17:22 +1100
                Re: Reference alex23 <wuwei23@gmail.com> - 2014-03-05 16:28 +1000
                Re: Reference Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-05 12:24 +0000
                Re: Reference Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-05 12:21 +0000
                Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-05 17:20 +1100
                Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-05 09:40 -0800
                Re: Reference Tim Chase <python.list@tim.thechases.com> - 2014-03-05 12:12 -0600
                Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-06 05:33 +1100
                Re: Reference Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-05 18:19 +0000
                Re: Reference Marko Rauhamaa <marko@pacujo.net> - 2014-03-05 22:23 +0200
                Re: Reference Grant Edwards <invalid@invalid.invalid> - 2014-03-05 20:31 +0000
                Re: Reference Marko Rauhamaa <marko@pacujo.net> - 2014-03-05 22:46 +0200
                Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-06 08:07 +1100
                Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-06 08:10 +1100
                Re: Reference Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-05 21:34 +0000
                Re: Reference Terry Reedy <tjreedy@udel.edu> - 2014-03-05 18:00 -0500
                Re: Reference Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-06 03:01 +0000
                Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-04 22:03 -0800
                Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-05 17:26 +1100
                Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-05 17:32 +1100
                Re: Reference Tim Chase <python.list@tim.thechases.com> - 2014-03-05 08:24 -0600
                Re: Reference Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-05 18:29 +0000
                Re: Reference Marko Rauhamaa <marko@pacujo.net> - 2014-03-05 22:34 +0200
                Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-06 08:01 +1100
                Re: Reference Marko Rauhamaa <marko@pacujo.net> - 2014-03-05 23:14 +0200
                Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-06 08:26 +1100
                Re: Reference Marko Rauhamaa <marko@pacujo.net> - 2014-03-05 23:50 +0200
                Re: Reference Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-06 00:35 +0000
                Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-06 11:50 +1100
                Re: Reference Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-06 17:46 +0000
                Re: Reference Tim Chase <python.list@tim.thechases.com> - 2014-03-05 15:33 -0600
                Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-06 08:37 +1100
                Re: Reference Marko Rauhamaa <marko@pacujo.net> - 2014-03-06 02:52 +0200
                Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-06 12:05 +1100
                Re: Reference alex23 <wuwei23@gmail.com> - 2014-03-06 12:12 +1000
                Re: Reference Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-05 21:46 +0000
                Re: Reference Marko Rauhamaa <marko@pacujo.net> - 2014-03-05 08:23 +0200
                Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-04 22:33 -0800
                Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-05 17:40 +1100
                Re: Reference Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-03-05 12:35 +0000
                Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-05 23:45 +1100
          Re: Reference Jerry Hill <malaclypse2@gmail.com> - 2014-03-04 10:19 -0500
            Re: Reference Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-03-04 15:42 +0000
              Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-05 03:02 +1100
                Re: Reference Roy Smith <roy@panix.com> - 2014-03-04 11:14 -0500
              Re: Reference MRAB <python@mrabarnett.plus.com> - 2014-03-04 17:12 +0000
            Re: Reference Rustom Mody <rustompmody@gmail.com> - 2014-03-04 08:24 -0800
          Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-05 02:25 +1100
          Re: Reference Antoon Pardon <antoon.pardon@rece.vub.ac.be> - 2014-03-05 14:37 +0100
      Re: Reference Steven D'Aprano <steve@pearwood.info> - 2014-03-04 03:59 +0000
    Re: Reference Ben Finney <ben+python@benfinney.id.au> - 2014-03-04 09:17 +1100
      Re: Reference Roy Smith <roy@panix.com> - 2014-03-03 18:02 -0500
        Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-04 10:09 +1100
        Re: Reference Steven D'Aprano <steve@pearwood.info> - 2014-03-04 04:38 +0000
  Re: Reference Terry Reedy <tjreedy@udel.edu> - 2014-03-03 13:48 -0500
    Re: Reference Steven D'Aprano <steve@pearwood.info> - 2014-03-04 03:45 +0000
    Re: Reference Alexander Blinne <news@blinne.net> - 2014-03-04 13:55 +0100
      Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-05 01:06 +1100
        Re: Reference Alexander Blinne <news@blinne.net> - 2014-03-04 22:53 +0100
          Re: Reference Chris Angelico <rosuav@gmail.com> - 2014-03-05 09:01 +1100

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