Class Variable Access and Assignment

Antoon Pardon apardon at forel.vub.ac.be
Fri Nov 4 09:23:05 CET 2005


Op 2005-11-03, Magnus Lycka schreef <lycka at carmen.se>:
> Antoon Pardon wrote:
>> There is no instance variable at that point. How can it add 2, to
>> something that doesn't exist at the moment.
>
> Because 'a += 1' is only a shorthand for 'a = a + 1' if a is an
> immutable object? Anyway, the behaviour is well documented.
>
> http://docs.python.org/ref/augassign.html says:
>
> An augmented assignment expression like x += 1 can be rewritten as x = x 
> + 1 to achieve a similar, but not exactly equal effect. In the augmented 
> version, x is only evaluated once.

Then couldn't we expect that the namespace resolution is also done
only once?

I say that if the introduction on += like operators implied that the
same mentioning of a name would in some circumstances be resolved to
two different namespaces, then such an introduction would better have
not occured.

Would it be too much to ask that in a line like.

  x = x + 1.

both x's would resolve to the same namespace?

-- 
Antoon Pardon



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