Annoying behaviour of the != operator
peter at engcorp.com
Wed Jun 8 18:48:54 EDT 2005
Christopher Subich wrote:
> Perhaps the language should offer
> the sensible default of (!=) == (not ==) if one of them but not the
> other is overriden, but still allow overriding of both.
I believe that's exactly what Jordan is promoting and, having been
bitten in exactly the same way I would support the idea. On the other
hand, I was bitten only _once_ and I suspect Jordan will never be bitten
by it again either. It's pretty hard to forget this wart once you
discover it, but I think the real reason to want to have it excised is
that a large number of people will have to learn this the hard way,
documentation (thankfully) not being shoved down one's throat as one
starts intrepidly down the road of overriding __eq__ for the first time.
> This would technically break backwards compatibilty, because it changes
> default behavior, but I can't think of any good reason (from a python
> newbie perspective) for the current counterintuitive behavior to be the
> default. Possibly punt this to Python 3.0?
I'd support an effort to fix it in 2.5 actually. I suspect nobody will
pipe up with code that would actually be broken by it, though some code
(as John Roth points out) doesn't *need* to have the automatic __ne__
even if it wouldn't break because of it.
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