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 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