Official definition of call-by-value (Re: Finding the instance reference...)

[Craig Allen]

> >> * Do all objects have values? (Ignore the Python
> >>  docs if necessary.)
>
> > If one allows null values, I am current thinking yes.
>
> I don't see a difference between a "null value"
> and not having a value.
>

I think the difference is concrete... an uninitialized variable in C
has no value, I'd say, because the value it will have is
indeterminate, it will be whatever happens to be sitting at that
location in memory, inconsistent.  If that variable is initialized to
some value representing "none", like NULL, then it has a consistent
value of "none".  There is no way to have an uninitialized variable in
python, so they are always consistently set, so they always have
values.

?