Home Original page

[Python-Dev] super() does not work during class initialization

Nick Coghlan ncoghlan at gmail.com
Wed Mar 25 13:32:03 CET 2015 
On 24 March 2015 at 08:22, Greg Ewing <greg.ewing at canterbury.ac.nz> wrote:
> Martin Teichmann wrote:
>>
>> maybe
>> we could just change the compiler to leave the order in which things are
>> defined
>> in a class in the class namespace, say as a member __order__? Then we
>> could
>> use plain-old dicts for the class namespace, and we would not slow down
>> class
>> creation (not that it matters much), as determining the order would happen
>> at
>> compile time.
>
>
> I don't think the compiler can determine the order in
> all cases. Consider:
>
>   class Spam:
>
>     if moon_is_full:
>       alpha = 1
>       beta = 2
>     else:
>       beta = 2
>       alpha = 1

This is also expected to work in class namespaces:

    locals()["alpha"] = 1

The language reference suggests it isn't, there's an open tracker
issue I filed some time ago to suggest clarifying it but haven't found
the time to actually sit down and come up with readable wording:
http://bugs.python.org/issue17960

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia
More information about the Python-Dev mailing list