Explanation of list reference

Ian Kelly ian.g.kelly at gmail.com
Sat Feb 15 09:08:07 CET 2014


On Fri, Feb 14, 2014 at 11:07 PM, Rustom Mody <rustompmody at gmail.com> wrote:
> On Saturday, February 15, 2014 10:50:35 AM UTC+5:30, Ian wrote:
>> This is false.  It happens to hold for CPython, but that's an
>> implementation detail.  The definition of object identity does not
>> depend on memory address.  It also doesn't have anything to do with
>> space-time coordinates.  The concept of object identity is an
>> abstraction, not an analogy from physics.
>
>> The language reference states, "Every object has an identity, a type
>> and a value. An object's identity never changes once it has been
>> created; you may think of it as the object's address in memory."
>> Okay, so that quote does bring up memory address, but in my
>> interpretation that's just an analogy to introduce the concept.  The
>> more important part of that sentence is the first part, which ties an
>> object's identity to its creation.  If two objects share the same
>> creation, then they're the same object.
>
> Whats the notion of object identity is the question.
> Ok so you reject the memory addr as an 'implementation detail'
> Then you are obliged to provide some other way of understanding object-identity

I thought that I did.  Repeating myself from what you quoted above:

    If two objects share the same creation, then they're the same object.



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