[Python-Dev] Third and hopefully final post: PEP 557, Data Classes (original) (raw)

Eric V. Smith eric at trueblade.com
Wed Nov 29 19:08:47 EST 2017

On 11/29/2017 6:51 PM, Carl Meyer wrote:

On 11/29/2017 03:26 PM, Eric V. Smith wrote:

I've posted a new version of PEP 557, it should soon be available at https://www.python.org/dev/peps/pep-0557/.

The only significant changes since the last version are: - changing the "compare" parameter to be "order", since that more accurately reflects what it does. - Having the combination of "eq=False" and "order=True" raise an exception instead of silently changing eq to True. There were no other issues raised with the previous version of the PEP. Not quite; I also raised the issue of isdataclass(ADataClass) returning False. I still think that's likely to be a cause of bug reports if left as-is.

Oops, sorry about that!

I think you're probably right. attr.has(), which is the equivalent attrs API, returns True for both classes and instances (although interestingly, the code only talks about it working on classes).

https://github.com/ericvsmith/dataclasses/issues/99

Eric.

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