Scope rule pecularities

[Antoon Pardon]

Op 2004-05-09, Josiah Carlson schreef <jcarlson at uci.edu>:
>>>Except when the /referenced object/ is immutable.  Name rebinding is 
>>>necessary to reference the newly created immutable object that was 
>>>created through the +=, -=, /=, %=, *=, &=, |=, or ^= operations.
>> 
>> 
>> IMO having operators that should work in place for object that
>> are immutable, sound contradictory. Having the following code:
>> 
>>   a = ...
>>   b = ...
>>   c = a
>>   a += b
>> 
>> I now expect a and c still to be the same object.
>
> If 'a' is mutable, and 'a' has the proper __iadd__ operator, then 'a' 
> and 'c' will be the same object when you are done.  However, integers, 
> strings, floats,... are immutable, so 'a' and 'c' won't be the same 
> object in those cases (Python only rebinds objects that are specified, 
> due to the whole "explicit is better than implicit" Zen).

Python does more than enought things in an implicit way.

> The real thing to remember is that Python isn't <insert the language you 
> expect Python to behave like>,

I think it is reasonable to expect a language to behave consistently.

> and your expectations are not what 
> actually happens.  What you think /should/ happen is not what /does/ 
> happen, and I am quite sure it is not what /Guido thinks should happen/.

So? Is what Guido thinks should happen above criticism. I think
that if what Guido thinks should happen makes the language
behave inconsistenly then 

> Once you wrap your mind around the implications of mutables and 
> immutables,

Well the more I wrap my mind around them, the less I like
them.

> and what you can/can't do with them, then perhaps the += 
> semantics will seem less confusing.

I would like to be able the understand what += does to
an object without the need of knowing it is mutable or
not.

-- 
Antoon Pardon