On 9 Sep, 2013, at 17:43, Mark Shannon <mark@hotpy.org> wrote:
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.
I did a benchmark run (see the pep for details) and that seems to indicate that the performance impact is very small, possibly because the patch keeps the attribute lookup cache used by _PyType_Lookup. Anyway, I'm glad that there is now some real discussion on the proposal. Not unsurprisingly I'd love to have this, or something simular, in 3.4. I had hoped to repost the PEP a while back with more information on how the API would affect PyObjC (code removal, performance impact), but haven't had time to move forward on that front :-( Ronald
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@stoneleaf.us <mailto:ethan@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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