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Groups > comp.lang.python > #96437

Re: Terminology: "reference" versus "pointer"

From Emile van Sebille <emile@fenx.com>
Subject Re: Terminology: "reference" versus "pointer"
Date 2015-09-12 10:14 -0700
References (6 earlier) <m2zj0ss2md.fsf@fastmail.com> <85mvws6z45.fsf_-_@benfinney.id.au> <mailman.404.1442032934.8327.python-list@python.org> <55f45396$0$1660$c3e8da3$5496439d@news.astraweb.com> <1dabdb08-2aee-4a53-bb57-1410edd372f6@googlegroups.com>
Newsgroups comp.lang.python
Message-ID <mailman.432.1442078061.8327.python-list@python.org> (permalink)

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On 9/12/2015 9:54 AM, Rustom Mody wrote:
> On Saturday, September 12, 2015 at 10:02:40 PM UTC+5:30, Steven D'Aprano wrote:
>> On Sat, 12 Sep 2015 02:42 pm, Random832 wrote:
>>
>>> Anyway, maybe we do need a term to distinguish Python/C#/Java pointers
>>> from C/C++ pointers - maybe call it a "non-arithmetic" pointer, since
>>> the key thing about it is you can't do pointer arithmetic on them to get
>>> the object "next to" the one it points at.
>>
>> How about *just don't call them pointers*? You know, since they aren't
>> pointers in the computer science sense.
>>
>> The Free On-line Dictionary of Computing defines "pointer":
>>
>>     1. <programming> An address, from the point of view of a
>>     programming language.  A pointer may be typed, with its type
>>     indicating the type of data to which it points.
>
> <snip>
>
>> Insisting that Python has pointers is like insisting that you use a text
>> editor by flipping bits. "What happens if I press Ctrl-X?" "Well, these
>> bits on the screen flip from black to white, these bits flip from white to
>> black, and these stay the same."
>>
>
> This is from the docs
> https://docs.python.org/3/library/functions.html#id
>
> id(object)
>
>      Return the "identity" of an object. This is an integer which is guaranteed to be unique and constant for this object during its lifetime. Two objects with non-overlapping lifetimes may have the same id() value.
>
>      CPython implementation detail: This is the address of the object in memory.

Quoting from above:

 >> The Free On-line Dictionary of Computing defines "pointer":
 >>
 >>     1. <programming> An address, from the point of view of a
 >>     programming language.

So, how does the CPython program access the contents given its 'address 
in memory'?  From the definition it would seem it's not a pointer, as 
from the perspective of the programming language, you can't get there 
from the id.

Look-ma,-no-pointers-ly y'rs,

Emile

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Re: Python handles globals badly. tdev@freenet.de - 2015-09-11 14:26 -0700
  Re: Python handles globals badly. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-11 23:50 +0200
    Re: Python handles globals badly. Michael Torrie <torriem@gmail.com> - 2015-09-11 18:01 -0600
      Re: Python handles globals badly. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-12 07:22 +0200
        Re: Python handles globals badly. MRAB <python@mrabarnett.plus.com> - 2015-09-12 18:05 +0100
          Re: Python handles globals badly. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-13 14:04 +0200
            Re: Python handles globals badly. Steven D'Aprano <steve@pearwood.info> - 2015-09-13 22:06 +1000
              Re: Python handles globals badly. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-13 14:11 +0200
                Re: Python handles globals badly. Ned Batchelder <ned@nedbatchelder.com> - 2015-09-13 05:17 -0700
                Re: Python handles globals badly. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-15 05:36 +0200
        Re: Python handles globals badly. Emile van Sebille <emile@fenx.com> - 2015-09-12 10:18 -0700
          Re: Python handles globals badly. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-13 14:06 +0200
            Re: Python handles globals badly. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-13 14:10 +0200
        Re: Python handles globals badly. Michael Torrie <torriem@gmail.com> - 2015-09-12 20:32 -0600
          Re: Python handles globals badly. "Skybuck Flying" <skybuck2000@hotmail.com> - 2015-09-13 14:05 +0200
    Re: Python handles globals badly. random832@fastmail.us - 2015-09-11 20:11 -0400
    Re: Python handles globals badly. Michael Torrie <torriem@gmail.com> - 2015-09-11 18:34 -0600
    Re: Python handles globals badly. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-09-12 03:57 +0100
    Re: Python handles globals badly. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-09-12 04:01 +0100
    Re: Python handles globals badly. Random832 <random832@fastmail.com> - 2015-09-12 00:06 -0400
    Re: Python handles globals badly. Random832 <random832@fastmail.com> - 2015-09-12 00:16 -0400
    Re: Python handles globals badly. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-09-12 05:17 +0100
    Terminology: “reference” versus “pointer” (was: Python handles globals badly.) Ben Finney <ben+python@benfinney.id.au> - 2015-09-12 14:27 +1000
    Re: Python handles globals badly. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-09-12 05:34 +0100
    Re: Python handles globals badly. Random832 <random832@fastmail.com> - 2015-09-12 00:34 -0400
    Re: Terminology: “reference” versus “pointer” Random832 <random832@fastmail.com> - 2015-09-12 00:42 -0400
      Re: Terminology: “reference” versus “pointer” Steven D'Aprano <steve@pearwood.info> - 2015-09-13 02:32 +1000
        Re: Terminology: "reference" versus "pointer" Rustom Mody <rustompmody@gmail.com> - 2015-09-12 09:54 -0700
          Re: Terminology: "reference" versus "pointer" Chris Angelico <rosuav@gmail.com> - 2015-09-13 03:06 +1000
          Re: Terminology: "reference" versus "pointer" Emile van Sebille <emile@fenx.com> - 2015-09-12 10:14 -0700
          Re: Terminology: "reference" versus "pointer" Steven D'Aprano <steve@pearwood.info> - 2015-09-13 03:24 +1000
            Re: Terminology: "reference" versus "pointer" Chris Angelico <rosuav@gmail.com> - 2015-09-13 03:34 +1000
    Re: Python handles globals badly. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-09-12 05:45 +0100
    Re: Terminology: “reference” versus “pointer” Ben Finney <ben+python@benfinney.id.au> - 2015-09-12 14:52 +1000
    Re: Terminology: “reference” versus “pointer” Random832 <random832@fastmail.com> - 2015-09-12 01:03 -0400
      Re: Terminology: “reference” versus “pointer” Steven D'Aprano <steve@pearwood.info> - 2015-09-13 02:50 +1000
        Re: Terminology: "reference" versus "pointer" Rustom Mody <rustompmody@gmail.com> - 2015-09-12 10:04 -0700
    Re: Python handles globals badly. Random832 <random832@fastmail.com> - 2015-09-12 01:07 -0400
    Re: Terminology: “reference” versus “pointer” Ben Finney <ben+python@benfinney.id.au> - 2015-09-12 15:20 +1000
    Re: Python handles globals badly. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-09-12 06:25 +0100
    Re: Python handles globals badly. Random832 <random832@fastmail.com> - 2015-09-12 01:35 -0400
    Re: Terminology: “reference” versus “pointer” Random832 <random832@fastmail.com> - 2015-09-12 01:42 -0400
    Re: Python handles globals badly. Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-09-12 06:54 +0100
    Re: Terminology: “reference” versus “pointer” Chris Angelico <rosuav@gmail.com> - 2015-09-12 16:02 +1000
    Re: Terminology: “reference” versus “pointer” Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-09-12 07:05 +0100
    Re: Python handles globals badly. Chris Angelico <rosuav@gmail.com> - 2015-09-12 16:13 +1000
    Re: Terminology: “reference” versus “pointer” Random832 <random832@fastmail.com> - 2015-09-12 02:15 -0400
    Re: Python handles globals badly. Random832 <random832@fastmail.com> - 2015-09-12 02:25 -0400
    Re: Terminology: “reference” versus “pointer” Ben Finney <ben+python@benfinney.id.au> - 2015-09-12 16:26 +1000
      Re: Terminology: "reference" versus "pointer" Rustom Mody <rustompmody@gmail.com> - 2015-09-12 05:46 -0700
        Re: Terminology: "reference" versus "pointer" Laura Creighton <lac@openend.se> - 2015-09-12 16:41 +0200
          Re: Terminology: "reference" versus "pointer" Rustom Mody <rustompmody@gmail.com> - 2015-09-12 08:13 -0700
            Re: Terminology: "reference" versus "pointer" rurpy@yahoo.com - 2015-09-12 09:17 -0700
              Re: Terminology: "reference" versus "pointer" Rustom Mody <rustompmody@gmail.com> - 2015-09-12 10:12 -0700
                Re: Terminology: "reference" versus "pointer" Steven D'Aprano <steve@pearwood.info> - 2015-09-13 04:14 +1000
              Re: Terminology: "reference" versus "pointer" Steven D'Aprano <steve@pearwood.info> - 2015-09-13 03:48 +1000
                Re: Terminology: "reference" versus "pointer" rurpy@yahoo.com - 2015-09-12 11:45 -0700
                Re: Terminology: "reference" versus "pointer" Steven D'Aprano <steve@pearwood.info> - 2015-09-13 22:50 +1000
                Re: Terminology: "reference" versus "pointer" Steven D'Aprano <steve@pearwood.info> - 2015-09-13 23:29 +1000
                Re: Terminology: "reference" versus "pointer" rurpy@yahoo.com - 2015-09-13 18:34 -0700
                Re: Terminology: "reference" versus "pointer" Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-09-14 04:34 +0100
                Re: Terminology: "reference" versus "pointer" rurpy@yahoo.com - 2015-09-12 12:58 -0700
                Re: Terminology: "reference" versus "pointer" Emile van Sebille <emile@fenx.com> - 2015-09-12 15:14 -0700
                Re: Terminology: "reference" versus "pointer" rurpy@yahoo.com - 2015-09-12 15:34 -0700
                Re: Terminology: "reference" versus "pointer" Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-09-13 00:14 +0100
                Re: Terminology: "reference" versus "pointer" Ned Batchelder <ned@nedbatchelder.com> - 2015-09-12 17:02 -0700
                Re: Terminology: "reference" versus "pointer" Rustom Mody <rustompmody@gmail.com> - 2015-09-12 17:28 -0700
                Re: Terminology: "reference" versus "pointer" rurpy@yahoo.com - 2015-09-12 17:44 -0700
                Re: Terminology: "reference" versus "pointer" Mark Lawrence <breamoreboy@yahoo.co.uk> - 2015-09-13 03:22 +0100
                Re: Terminology: "reference" versus "pointer" Ned Batchelder <ned@nedbatchelder.com> - 2015-09-12 19:25 -0700
                Re: Terminology: "reference" versus "pointer" Michael Torrie <torriem@gmail.com> - 2015-09-12 20:35 -0600
                Re: Terminology: "reference" versus "pointer" Ben Finney <ben+python@benfinney.id.au> - 2015-09-13 12:42 +1000
                Re: Terminology: "reference" versus "pointer" rurpy@yahoo.com - 2015-09-13 08:31 -0700
                Re: Terminology: "reference" versus "pointer" Chris Angelico <rosuav@gmail.com> - 2015-09-14 01:39 +1000
                Re: Terminology: "reference" versus "pointer" Ben Finney <ben+python@benfinney.id.au> - 2015-09-14 06:48 +1000
                Re: Terminology: "reference" versus "pointer" rurpy@yahoo.com - 2015-09-13 18:13 -0700
                Re: Terminology: "reference" versus "pointer" Dennis Lee Bieber <wlfraed@ix.netcom.com> - 2015-09-13 12:32 -0400
                Re: Terminology: "reference" versus "pointer" rurpy@yahoo.com - 2015-09-12 17:23 -0700
                Re: Terminology: "reference" versus "pointer" Rustom Mody <rustompmody@gmail.com> - 2015-09-12 16:39 -0700
                Re: Terminology: "reference" versus "pointer" Chris Angelico <rosuav@gmail.com> - 2015-09-13 10:19 +1000
                Re: Terminology: "reference" versus "pointer" rurpy@yahoo.com - 2015-09-12 17:25 -0700
                Re: Terminology: "reference" versus "pointer" rurpy@yahoo.com - 2015-09-12 18:07 -0700
            Re: Terminology: "reference" versus "pointer" Akira Li <4kir4.1i@gmail.com> - 2015-09-12 20:54 +0300
              Re: Terminology: "reference" versus "pointer" Rustom Mody <rustompmody@gmail.com> - 2015-09-12 11:21 -0700
                Re: Terminology: "reference" versus "pointer" Jussi Piitulainen <harvesting@makes.email.invalid> - 2015-09-12 23:02 +0300
                Re: Terminology: "reference" versus "pointer" Random832 <random832@fastmail.com> - 2015-09-12 17:10 -0400
                Re: Terminology: "reference" versus "pointer" Steven D'Aprano <steve@pearwood.info> - 2015-09-13 12:30 +1000
                Re: Terminology: "reference" versus "pointer" Jussi Piitulainen <harvesting@makes.email.invalid> - 2015-09-13 09:40 +0300
                Re: Terminology: "reference" versus "pointer" Akira Li <4kir4.1i@gmail.com> - 2015-09-12 23:13 +0300
                Re: Terminology: "reference" versus "pointer" Random832 <random832@fastmail.com> - 2015-09-12 17:27 -0400
                Re: Terminology: "reference" versus "pointer" Akira Li <4kir4.1i@gmail.com> - 2015-09-13 21:04 +0300
                Re: Terminology: "reference" versus "pointer" Chris Angelico <rosuav@gmail.com> - 2015-09-14 05:03 +1000
                Re: Terminology: "reference" versus "pointer" Random832 <random832@fastmail.com> - 2015-09-13 15:04 -0400
                Re: Terminology: "reference" versus "pointer" Akira Li <4kir4.1i@gmail.com> - 2015-09-14 02:17 +0300
                Re: Terminology: "reference" versus "pointer" Steven D'Aprano <steve@pearwood.info> - 2015-09-14 11:10 +1000
                Re: Terminology: "reference" versus "pointer" Akira Li <4kir4.1i@gmail.com> - 2015-09-14 04:22 +0300
                Re: Terminology: "reference" versus "pointer" Steven D'Aprano <steve@pearwood.info> - 2015-09-14 12:38 +1000
                Re: Terminology: "reference" versus "pointer" Akira Li <4kir4.1i@gmail.com> - 2015-09-14 06:23 +0300
                Re: Terminology: "reference" versus "pointer" Steven D'Aprano <steve@pearwood.info> - 2015-09-15 02:59 +1000
                Re: Terminology: "reference" versus "pointer" Akira Li <4kir4.1i@gmail.com> - 2015-09-14 20:24 +0300
                Re: Terminology: "reference" versus "pointer" Ned Batchelder <ned@nedbatchelder.com> - 2015-09-14 11:29 -0700
                Re: Terminology: "reference" versus "pointer" Akira Li <4kir4.1i@gmail.com> - 2015-09-14 22:30 +0300
                Re: Terminology: "reference" versus "pointer" Ned Batchelder <ned@nedbatchelder.com> - 2015-09-14 13:16 -0700
                Re: Terminology: "reference" versus "pointer" Akira Li <4kir4.1i@gmail.com> - 2015-09-14 23:32 +0300
                Re: Terminology: "reference" versus "pointer" Chris Angelico <rosuav@gmail.com> - 2015-09-14 11:30 +1000
                Re: Terminology: "reference" versus "pointer" Akira Li <4kir4.1i@gmail.com> - 2015-09-14 05:26 +0300
                Re: Terminology: "reference" versus "pointer" Chris Angelico <rosuav@gmail.com> - 2015-09-14 09:52 +1000
                Re: Terminology: "reference" versus "pointer" Akira Li <4kir4.1i@gmail.com> - 2015-09-14 03:30 +0300
                Re: Terminology: "reference" versus "pointer" Chris Angelico <rosuav@gmail.com> - 2015-09-14 10:58 +1000
                Re: Terminology: "reference" versus "pointer" Random832 <random832@fastmail.com> - 2015-09-13 19:38 -0400
                Re: Terminology: "reference" versus "pointer" Akira Li <4kir4.1i@gmail.com> - 2015-09-14 17:48 +0300
                Re: Terminology: "reference" versus "pointer" Random832 <random832@fastmail.com> - 2015-09-14 11:10 -0400
                Re: Terminology: "reference" versus "pointer" Steven D'Aprano <steve@pearwood.info> - 2015-09-15 03:03 +1000
                Re: Terminology: "reference" versus "pointer" Random832 <random832@fastmail.com> - 2015-09-14 13:34 -0400
                Re: Terminology: "reference" versus "pointer" Steven D'Aprano <steve@pearwood.info> - 2015-09-16 00:26 +1000
                Re: Terminology: "reference" versus "pointer" Emile van Sebille <emile@fenx.com> - 2015-09-14 10:51 -0700
                Re: Terminology: "reference" versus "pointer" Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2015-09-16 20:14 +1200
                Re: Terminology: "reference" versus "pointer" Chris Angelico <rosuav@gmail.com> - 2015-09-16 18:18 +1000
                Re: Terminology: "reference" versus "pointer" Ben Finney <ben+python@benfinney.id.au> - 2015-09-16 18:24 +1000
                Re: Terminology: "reference" versus "pointer" Chris Angelico <rosuav@gmail.com> - 2015-09-16 18:33 +1000
                Re: Terminology: "reference" versus "pointer" Chris Angelico <rosuav@gmail.com> - 2015-09-15 03:59 +1000
                Re: Terminology: "reference" versus "pointer" Random832 <random832@fastmail.com> - 2015-09-14 14:02 -0400
                Re: Terminology: "reference" versus "pointer" Steven D'Aprano <steve@pearwood.info> - 2015-09-16 00:14 +1000
                Re: Terminology: "reference" versus "pointer" Akira Li <4kir4.1i@gmail.com> - 2015-09-14 20:45 +0300
                Re: Terminology: "reference" versus "pointer" Random832 <random832@fastmail.com> - 2015-09-14 14:00 -0400
                Re: Terminology: "reference" versus "pointer" Akira Li <4kir4.1i@gmail.com> - 2015-09-14 21:17 +0300
        Re: Terminology: "reference" versus "pointer" Steven D'Aprano <steve@pearwood.info> - 2015-09-13 03:08 +1000
          Re: Terminology: "reference" versus "pointer" Rustom Mody <rustompmody@gmail.com> - 2015-09-12 10:26 -0700
        Re: Terminology: "reference" versus "pointer" Ben Finney <ben+python@benfinney.id.au> - 2015-09-13 11:13 +1000
    Re: Python handles globals badly. Chris Angelico <rosuav@gmail.com> - 2015-09-12 16:27 +1000
    Re: Terminology: “reference” versus “pointer” Chris Angelico <rosuav@gmail.com> - 2015-09-12 16:31 +1000
  Re: Python handles globals badly. Ian Kelly <ian.g.kelly@gmail.com> - 2015-09-11 16:10 -0600
  Re: Python handles globals badly. MRAB <python@mrabarnett.plus.com> - 2015-09-12 00:03 +0100

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