[Python-Dev] PEP 520: Ordered Class Definition Namespace

[Victor Stinner]

> Abstract
> ========
>
> This PEP changes the default class definition namespace to ``OrderedDict``.
> Furthermore, the order in which the attributes are defined in each class
> body will now be preserved in ``type.__definition_order__``.  This allows
> introspection of the original definition order, e.g. by class decorators.
>
> Note: just to be clear, this PEP is *not* about changing ``__dict__`` for
> classes to ``OrderedDict``.

What is the cost in term of performance?

What can be slower: define a new class and/or instanciate a class?

Victor