[Python-Dev] Meta-reflections (original) (raw)

Martin v. Loewis martin@v.loewis.de
18 Feb 2002 22:31:22 +0100

Kevin Jacobs <jacobs@penguin.theopalgroup.com> writes:

1) Should class instances explicitly/directly know all of their attributes?

Since types are classes, this is the same question as "should type instances know all their attributes?" I don't think they should, in general: For example, there is no way to find out whether a string object has an interned pointer, and I don't think there should be.

The slots aren't really different here. In fact, if you do

class Spam(object): slots = ('a','b')

s = Spam() s.a = {} del Spam.a

you loose access to s.a, even though it is still available (I guess it is actually a bug that cyclic garbage collection won't find cycles involving slots).

2) Should attribute access follow the same resolution order rules as methods?

Yes, I think so.

4) Should slots be flat?

Yes. They should also be a property of the type, not a member of the dict of the type, and they should be a tuple of member object, not a list of strings. It might be reasonable to call this property members.

> ('c','d') # current behavior or > ('a','b','c','d') # alternate behavior

Neither, nor; assuming you meant Bar to inherit from Foo, it should be

(<member 'a' of 'Foo' objects>, <member 'b' of 'Foo' objects>, <member 'c' of 'Bar' objects>, <member 'd' of 'Bar' objects>)

Regards, Martin