Terminology: "reference" versus "pointer"

Random832 random832 at fastmail.com
Sun Sep 13 21:04:16 CEST 2015


Akira Li <4kir4.1i at gmail.com> writes:
> I'm not sure what "parcel tags" model is but if you mean these
> pictures[1] than it works in this case as well as any other (take *a*,
> *b* nametags, put them on the corresponding balloons that represents
> list objects).
>
> The only names left are *a* and *b* that refer to the corresponding
> lists. There is no ambiguity there to put *a*, *b* nametags.

But how do you make an a[0][0]/a[1][0] nametag to put on the "1" object?

> Lists as any other containers contain references to other objects and
> therefore "box and arrows" model provides _more details_ here[2,3]

Right, but why not use the *same* model to represent *namespaces*?

It seems like the "tags" model only exists to make the incorrect claim
that python doesn't have variables (the boxes are variables).

>> If the "parcel tags" model can't show it, then the "parcel tag" model
>> clearly is not a correct and complete depiction of how Python actually
>> works.
>> (If I were drawing a picture rather than ASCII I'd add something to make
>> it clear that the pairs shown are list objects Like, it's a circle with
>> the word "list" and two pointer-boxes inside it.)
>
> "correct and complete" is impossible in the general case for any
> model.

Everything you wrote here has the same issue: The "objects" you are
talking about do not physically exist, but are simply the result of
calling a method on the object. Therefore they do not *belong* on the
diagram, and the diagram not showing them does not mean the diagram is
not complete.



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