On Wed, Aug 26, 2020 at 10:10 AM Ricky Teachey <ri...@teachey.org> wrote:
> *Objection 1: Slowing Things Down*
> ...for actual implementation... we could wrap the existing item dunder
> methods automatically at class creation time only when the new dunder
> attribute is present. If it is not present, nothing happens. In other
> words, what has been described as the "default key or index
> translation function" already exists. Let's not change that at all for
> classes that do not choose to use it.
>
After reading Steve's response to me in the other thread, where he says
this:
On Wed, Aug 26, 2020 at 9:48 AM Steven D'Aprano <st...@pearwood.info> wrote:
> On Tue, Aug 25, 2020 at 10:51:42PM -0400, Ricky Teachey wrote:
>
> > Well it would not have to inspect the signature on every subscript call,
>
> Python is a very dynamic language and objects can change their own
> methods and even their class at any time, so, yes, it will have to
> inspect the signature on every call. Otherwise you are changing
> the language execution model.
>
> Demonstration:
>
>
> py> class Dynamic:
> ... def __getitem__(self, arg):
> ... print("original")
> ... type(self).__getitem__ = lambda *args:
> print("replaced")
> ...
> py>
> py> x = Dynamic()
> py> x[0]
> original
> py> x[0]
> replaced
>
...I am less optimistic that this can be implemented without slowing things
down. And wrapping the methods at class creation time may not be a good
idea after all.
I am a little crestfallen now, because I still think the core of the idea
is a wonderful idea.
Is there another clever way this could be implemented, to avoid the
slowdown of existing code?
---
Ricky.
"I've never met a Kentucky man who wasn't either thinking about going home
or actually going home." - Happy Chandler
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