[Python-Dev] __contains__ hook

[Fred L. Drake, Jr.]

Moshe Zadka writes:
 > I totally agree with Guido -- for me, the whole point of this hack is
 > to avoid people asking for 'in' in dicts: this way we can code a class

  That's not a good enough reason to add it.

 > I'm not quite sure where we want to put the C API version of __contains__
 > - I'd add a tp_as_set, but the only method seems to be 'in', so it seems
 > like a waste of valuable real-estate before we are driven into
 > non-backwards-compatability. I think I should at least ask permission from
 > the owner before I move over there, trampling everything in my way<wink>

  I suspect there will be fairly few set implementations in C; there
will be something like a dictionary (kjSet might be updated, for
instance), but that's probably about it.
  The "in"/"not in" operation can work off the contains slot, and I
expect set union would be expressed as +, which is already in the
as_number structure.  Everything else should probably be implemented
as a method or a function rather than as an operator overload.


  -Fred

--
Fred L. Drake, Jr.	  <fdrake at acm.org>
Corporation for National Research Initiatives