On 6/8/2016 4:07 AM, Victor Stinner wrote:
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?
A class is defined once, used many times to instantiate instances. Each
instance is typically used many times, with many lookups. So it is
self.class_attribute lookups, like method lookups, that likely matter
the most, and which are not changed by the PEP.
--
Terry Jan Reedy
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