[Python-Dev] Why doesn't `functools.total_ordering` use the existing ordering methods?

[Raymond Hettinger]

On Apr 25, 2011, at 11:43 AM, cool-RR wrote:

> Today I was trying to use `total_ordering` for the first time. I was expecting that in order to implement e.g. `x > y` it would do `not x < y and not x == y`, assuming that `__lt__`  and `__eq__` are defined.

This was fixed.  The current code has:

    convert = {
        '__lt__': [('__gt__', lambda self, other: not (self < other or self == other)),
                   ('__le__', lambda self, other: self < other or self == other),
                   ('__ge__', lambda self, other: not self < other)],
        '__le__': [('__ge__', lambda self, other: not self <= other or self == other),
                   ('__lt__', lambda self, other: self <= other and not self == other),
                   ('__gt__', lambda self, other: not self <= other)],
        '__gt__': [('__lt__', lambda self, other: not (self > other or self == other)),
                   ('__ge__', lambda self, other: self > other or self == other),
                   ('__le__', lambda self, other: not self > other)],
        '__ge__': [('__le__', lambda self, other: (not self >= other) or self == other),
                   ('__gt__', lambda self, other: self >= other and not self == other),
                   ('__lt__', lambda self, other: not self >= other)]
    }


> Why not have `total_ordering` work in the way I suggested?

To avoid needless posts, you should use the tracker.


Raymond