[Python-Dev] Dict suppressing exceptions

[Guido van Rossum]

On 8/10/06, "Martin v. Löwis" <martin at v.loewis.de> wrote:
> Guido van Rossum schrieb:
> > Hmm... Here's an idea... How about we change unicode-vs-str __eq__ to
> > issue a warning (and return False) instead of raising
> > UnicodeException?
>
> I'm in favour of having this __eq__ just return False. I don't think
> the warning is necessary, and believe that people will complain about
> getting it, but if that is the only way to achieve consensus,
> so be it.

Not sure I agree. I think that users would find it disturbing (and it
could hide bugs) if u"\xff" == "\xff" returned False without warning
while u"\x7f" == "\x7f" returns True.

> > A warning would arguably have the same helping effect. (I suspect
> > actually that we would have used warnings all along except we didn't
> > have the warning framework when unicode was first introduced.)
>
> I believe we would have neither had we rich comparisons available
> at the time. That unicode-vs-str-__eq__ raises an exception is just
> a fall-out of not supporting __cmp__ (and it is good that __cmp__
> is not supported - there is no meaningful way to order str/unicode
> if the string is not in the system encoding).

Maybe. I agree that 3-way compare has no business guessing the
ordering of u"\xff" and "\xff". I'm not so sure that if we'd had rich
comparison we'd have chosen __eq__ to return False for these.

-- 
--Guido van Rossum (home page: http://www.python.org/~guido/)