[Python-3000] Please re-add __cmp__ to python 3000

[Steven Bethard]

On 10/30/07, Adam Olsen <rhamph at gmail.com> wrote:
> cmp and __cmp__ are doomed, due to unorderable types now raising exceptions:
>
> >>> cmp(3, 'hello')
> Traceback (most recent call last):
>   File "<stdin>", line 1, in <module>
> TypeError: unorderable types: int() < str()
> >>> 3 == 'hello'
> False
>
> A mixin for __cmp__ would be sufficient for scalars (where you can
> avoid this exception and your size is constant), but not for
> containers (which need to avoid inappropriate types and wish to avoid
> multiple passes.)

I don't understand this conclusion.  If you start comparing things
that are unorderable, you'll get an exception.  But cmp() still makes
sense when you compare other things::

    >>> cmp((1, 'a', 4.5), (1, 'a', 6.2))
    -1
    >>> cmp([6, 5, 4], [6, 4, 5])
    1

I definitely don't want any cmp/__cmp__ implementation that swallows
exceptions when the types don't align, e.g.::

    >>> cmp((1, 'a'), ('a', 1))
    Traceback (most recent call last):
      File "<stdin>", line 1, in <module>
    TypeError: unorderable types: int() < str()

STeVe
-- 
I'm not *in*-sane. Indeed, I am so far *out* of sane that you appear a
tiny blip on the distant coast of sanity.
        --- Bucky Katt, Get Fuzzy