[Python-Dev] PEP 447: add type.__locallookup__

Mark Shannon mark at hotpy.org
Mon Sep 9 17:43:31 CEST 2013


I would like time to investigate this further, but at the moment I think it will either make attribute lookup poorly defined or slow.

Of the top of my head, the problem as a I see it is basically this:
Currently, type.__getattribute__() is a fixed point in the lookup of attributes.
The proposal means that a fixed point is not reached until the cls parameter of type.__getattribute__() is either object or type,
otherwise type.__getattribute__() and type.__locallookup__ must bounce back and forth.

This will slow down *every* attribute lookup for what is a fairly obscure use case.

Cheers,
Mark.

On 09/09/13 16:27, Guido van Rossum wrote:
> Let's just accept this PEP. It looks like a nice addition to the metaclass machinery and I don't think we'll get much more useful feedback by waiting.
>
>
> On Mon, Sep 9, 2013 at 7:30 AM, Ethan Furman <ethan at stoneleaf.us <mailto:ethan at stoneleaf.us>> wrote:
>
>     On 07/30/2013 11:17 PM, Ronald Oussoren wrote:
>
>
>         And something I forgot to ask: is anyone willing to be the BDFL-Delegate for
>         PEP 447?
>
>
>     *Bump*.
>
>     It would be nice if this could make into 3.4.
>
>     --
>     ~Ethan~
>
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