[Python-Dev] PyObject_RichCompareBool identity shortcut

[Nick Coghlan]

On Fri, Apr 29, 2011 at 2:55 AM, Guido van Rossum <guido at python.org> wrote:
> Raymond strongly believes that containers must be allowed to use the
> modified definition, I believe purely for performance reasons.
> (Without this rule, a list or tuple could not even cut short being
> compared to *itself*.) It seems you are in that camp too.

I'm a fan of the status quo, but not just for performance reasons -
there is quite a bit of set theory that breaks once you allow
non-reflexive equality*, so it makes sense to me to make it official
that containers should ignore any non-reflexivity they come across.

*To all the mathematicians in the audience yelling at their screens
that the very idea of "non-reflexive equality" is an oxymoron... yes,
I know :P

Cheers,
Nick.

P.S. It's hard to explain the slightly odd point of view that seeing
standard arithmetic constructed from Peano's Axioms and set theory can
give you on discussions like this. It's a seriously different (and
strange) way of thinking about the basic arithmetic constructs we
normally take for granted, though :)

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia