learning python ...

[hw]

On 5/24/21 4:37 PM, Chris Angelico wrote:
> On Tue, May 25, 2021 at 12:31 AM Michael Torrie <torriem at gmail.com> wrote:
>>
>> On 5/24/21 8:24 AM, Chris Angelico wrote:
>>> On Tue, May 25, 2021 at 12:18 AM hw <hw at adminart.net> wrote:
>>>> There are more alternatives:  Python might create a new variable with
>>>> the same name and forget about the old one.  Or it doesn't forget about
>>>> the old one and the old one becomes inaccessible (unless you have a
>>>> reference to it, if there is such a thing in python).  How do you call that?
>>>
>>> It's the latter option: create a new variable, and the old one becomes
>>> inaccessible. That's called "shadowing". It's how scoping works in
>>> most languages (called "lexical scope").
>>
>> Is it really shadowing, though?  The old one is not only inaccessible,
>> it's possibly reaped by the garbage collector, no?  Both nums are in the
>> same scope so the one overwrote the other in the name table.  Or am I
>> missing something.
>>
> 
> We're talking about many different things. If it's simply "num = ..."
> followed by "num = ...", then it's not a new variable or anything,
> it's simply rebinding the same name. But when you do "int = ...", it's
> shadowing the builtin name.

Why?  And how is that "shadowing"?

What if I wanted to re-define the built-in thing?