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[Python-Dev] PEP-435 reference implementation

Nick Coghlan ncoghlan at gmail.com
Fri May 3 03:10:04 CEST 2013 
On Thu, May 2, 2013 at 11:37 AM, Steven D'Aprano <steve at pearwood.info> wrote:
> On 02/05/13 08:54, Nick Coghlan wrote:
>
>> If enums had an "as_dict" method that returned an ordered dictionary, you
>> could do:
>>
>> class MoreColors(Enum):
>>      locals().update(Colors.as_dict())
>
>
>
> Surely that is an implementation-specific piece of code? Writing to locals()
> is not guaranteed to work, and the documentation warns against it.
>
> http://docs.python.org/3/library/functions.html#locals

I've long thought we should stop being wishy-washy about modification
of locals(), and make the current CPython behaviour part of the
language spec:

- at module scope, locals() must return the same thing as globals(),
which must be the actual module namespace
- at class scope, it must return the namespace returned by __prepare__()
- at function scope, it returns a snapshot of the current locals and
free variables, and thus does not support modifications (and may not
see subsequent changes)

I'll start a separate thread about that.

Cheers,
Nick.

--
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia
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