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

Serhiy Storchaka storchaka at gmail.com
Thu Nov 30 06:56:52 EST 2017

30.11.17 03:02, Guido van Rossum пише:

I tried to look up the discussion but didn't find much except that you flagged this as an issue. To repeat, your concern is that isdataclass() applies to instances, not classes, which is how Eric has designed it, but you worry that either through the name or just because people don't read the docs it will be confusing. What do you suppose we do? I think making it work for classes as well as for instances would cause another category of bugs (confusion between cases where a class is needed vs. an instance abound in other situations -- we don't want to add to that). Maybe it should raise TypeError when passed a class (unless its metaclass is a dataclass)? Maybe it should be renamed to isdataclassinstance()? That's a mouthful, but I don't know how common the need to call this is, and people who call it a lot can define their own shorter alias.

There is isdatadescriptor() which is not too shorter.

More information about the Python-Dev mailing list