[Python-Dev] PEP 520: Ordered Class Definition Namespace
ericsnowcurrently at gmail.com
Fri Jun 10 12:42:32 EDT 2016
On Thu, Jun 9, 2016 at 2:39 PM, Nick Coghlan <ncoghlan at gmail.com> wrote:
> I'm guessing Ethan is suggesting defining it as:
> __definition_order__ = tuple(ns["__definition_order__"])
> When the attribute is present in the method body.
Ah. I'd rather stick to "consenting adults" in the case that
__definition_order__ is explicitly set. We'll strongly recommend
setting it to None or a tuple of identifier strings.
> That restriction would be comparable to what we do with __slots__ today:
> >>> class C:
> ... __slots__ = 1
> Traceback (most recent call last):
> File "<stdin>", line 1, in <module>
> TypeError: 'int' object is not iterable
Are you suggesting that we require it be a tuple of identifiers (or
None) and raise TypeError otherwise, similar to __slots__? The
difference is that __slots__ has specific type requirements that do
not apply to __definition_order__, as well as a different purpose.
__definition_order__ is about preserving definition-type info that we
are currently throwing away.
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