On 09/08/2017 11:38 AM, Steven D'Aprano wrote:
On Fri, Sep 08, 2017 at 10:37:12AM -0700, Nick Coghlan wrote:
def __eq__(self, other):
if other.__class__ is self.__class__:
return (self.name, self.unit_price, self.quantity_on_hand) ==
(other.name, other.unit_price, other.quantity_on_hand)
return NotImplemented
My one technical question about the PEP relates to the use of an exact
type check in the comparison methods, rather than "isinstance(other,
self.__class__)".
I haven't read the whole PEP in close detail, but that method stood out
for me too. Only, unlike Nick, I don't think I agree with the decision.
I'm also not convinced that we should be adding ordered comparisons
(__lt__ __gt__ etc) by default, if these DataClasses are considered
more like structs/records than tuples. The closest existing equivalent
to a struct in the std lib (apart from namedtuple) is, I think,
SimpleNamespace, and they are unorderable.
I'll split the difference. ;)
I agree with D'Aprano that an isinstance check should be used, but I disagree with him about the rich comparison methods
-- please include them. I think unordered should only be the default when order is impossible, extremely difficult, or
nonsensical.
--
~Ethan~
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