[Python-ideas] Eliminating special method lookup (was Re: Missing Core Feature: + - * / | & do not call __getattr__)

[Brendan Barnwell]

On 2015-12-04 12:02, Andrew Barnert wrote:
> So, maybe the way to get from here to there is to explicitly document
> the methods CPython treats as magic methods, and allow only allow
> other implementations to do the same for (a subset of) the same, and
> people can gradually tackle and remove parts of that list as people
> come up with ideas, and if the list eventually becomes empty (or gets
> to the point where it's 2 rare things that aren't important enough to
> keep extra complexity in the language), then the whole notion of
> special method lookup can finally go away.

	Presumably you mean "treats as magic methods for the purposes of this 
lookup short-circuiting"?  To me the term "magic methods" just means the 
ones that are implicitly invoked by syntax (e.g., operator overloading), 
and what those are is already documented.

	If that's what you mean, I agree that would be a good starting point. 
I am always nervous when the docs say the kind of thing they say for 
this, which is "implicit special method lookup generally also bypasses 
the __getattribute__() method even of the object’s metaclass". 
"Generally"?  What does that mean?  It seems to me that whether and when 
__getattribute__ is called should be a clearly-specified part of the 
semantics of magic methods, and it's somewhat disturbing that it doesn't 
seem to be.

---
Brendan Barnwell
"Do not follow where the path may lead.  Go, instead, where there is no
path, and leave a trail."
    --author unknown