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About the implementation of del in Python 3


MRAB <python at mrabarnett.plus.com> writes:

> On 2017-07-06 15:29, Jussi Piitulainen wrote:
>> Marko Rauhamaa writes:
>>
>>> While talking about addresses might or might not be constructive,
>>> let me just point out that there is no outwardly visible distinction
>>> between "address" or "identity".
>>
>> With a generational or otherwise compacting garbage collector there
>> would be. I believe that to be a valid implementation strategy.
>>
>> Or you are using "address" in some abstract sense so that the
>> "address" does not change when the internal representation of the
>> object is moved to another location.
>>
>>> Ignoring the word that is used to talk about object identity, it
>>> would be nice to have a precise formal definition for it. For
>>> example, I know that any sound implementation of Python would
>>> guarantee:
>>>
>>>     >>> def f(a): return a
>>>     ...
>>>     >>> a = object()
>>>     >>> a is f(a)
>>>     True
>>>
>>> But how do I know it?
>>
>> For me it's enough to know that it's the object itself that is passed
>> around as an argument, as a returned value, as a stored value, as a
>> value of a variable. This is the basic fact that lets me understand
>> the behaviour and performance of programs.
>>
> Perhaps you should be thinking of it as passing around the end of a
> piece of string, the other end being tied to the object itself. :-)

I don't find that helpful, and I don't find myself in need of such help.
Most of the time that piece of string is (those pieces of string are)
just a distraction to me. They get in the way. So I *don't*.