[Python-Dev] PEP 520: Ordered Class Definition Namespace (round 3)

[Émanuel Barry]

> From: Eric Snow
> Sent: Saturday, June 11, 2016 11:02 PM
> To: Émanuel Barry
> Cc: Python-Dev
> Subject: Re: [Python-Dev] PEP 520: Ordered Class Definition Namespace
> (round 3)
> 
> On Sat, Jun 11, 2016 at 7:51 PM, Émanuel Barry <vgr255 at live.ca> wrote:
> >> From: Eric Snow
> >>   1. if ``__definition_order__`` is defined in the class body then it
> >>      must be a ``tuple`` of identifiers or ``None``; any other value
> >>      will result in ``TypeError``
> >
> > Why not just any arbitrary iterable, which get converted to a tuple at
> > runtime?
> 
> An arbitrary iterable does not necessarily infer a definition order.
> For example, dict is an iterable but the order is undefined.  Also,
> I'd rather favor simplicity for this (most likely) uncommon corner
> case of manually setting __definition_order__, particularly at the
> start.  If it proves to be a problematic restriction in the future we
> can loosen it.

Point. This can always be revised later (I'm probably overthinking this as always ;)

> 
> -eric

-Emanuel