Boilerplate in rich comparison methods

[Steven D'Aprano]

I'm writing a class that implements rich comparisons, and I find myself
writing a lot of very similar code. If the calculation is short and
simple, I do something like this:


class Parrot:
    def __eq__(self, other):
        return self.plumage() == other.plumage()
    def __ne__(self, other):
        return self.plumage() != other.plumage()
    def __lt__(self, other):
        return self.plumage() < other.plumage()
    def __gt__(self, other):
        return self.plumage() > other.plumage()
    def __le__(self, other):
        return self.plumage() <= other.plumage()
    def __ge__(self, other):
        return self.plumage() >= other.plumage()

If the comparison requires a lot of work, I'll do something like this:

class Aardvark:
    def __le__(self, other):
        return lots_of_work(self, other)
    def __gt__(self, other):
        return not self <= other
    # etc.

But I can't help feeling that there is a better way. What do others do?



-- 
Steven.