[Python-3000] PEP 3119 - Introducing Abstract Base Classes

[Thomas Lotze]

Jim Jewett wrote:

> Yes, but it is a TypeError today.  Is it worth the backwards
> compatibility?

I'd say yes for the sake of doing things right, in particular as we are
talking about Py3k, but then I don't think I have a good picture of all
the things that would be broken by this change.

> That makes sense.  Looking at unordered containers like sets, should
> 
> {"a", "b"} in {"b", "a", "d"} be able to return true, by deriving from
> Searchable?

No. {"a", "b"} clearly is a subset of {"b", "a", "d"}, not an element. So
{"a", "b"} < {"b", "a", "d"}, but {"a", "b"} not in {"b", "a", "d"}.

-- 
Thomas