Call by binding [was Re: [Tutor] beginning to code]

[Chris Angelico]

On Tue, Sep 26, 2017 at 3:04 AM, Antoon Pardon
<antoon.pardon at rece.vub.ac.be> wrote:
> On 25-09-17 16:29, Marko Rauhamaa wrote:
>> Antoon Pardon <antoon.pardon at vub.be>:
>>
>>> Op 25-09-17 om 15:16 schreef Marko Rauhamaa:
>>>> No, I'm not. I'm talking about pointers in the abstract sense, both in
>>>> case of Python and Pascal. Neither language gives any hint as to the
>>>> physical nature of the pointer.
>>>
>>> Yes you are. Python doesn't have pointers at the language level. So if
>>> you start talking pointers you are talking about implementations
>>> however abstract.
>>
>> It is difficult to say what is the "native" Python term for the thing.
>> "Binding," maybe? The language spec fails to give it a name.
>>
>> However, when comparing different languages, you had better unify the
>> terminology or you'll be confused by purely terminological issues.
>
> Fine, you have two mappings, a mapping from names to identities and a
> mapping from identities to values. In languages like C, Pascal, ...
> an assignment changes the mapping between the identities and the
> values. In languages like Python, Smalltalk, ... an assignment
> changes the mapping between the names and the identities.

If by "identity" you mean the integer values returned by id(), then
nope, you're still wrong - there is no mapping from identities to
values. There is a mapping from name to object/value, and from an
object, you can determine its identity. If you like, there's a mapping
from values to identities, but not the other way around.

Unless, of course, you can find something in the Python documentation
that supports this two-step indirection?

ChrisA