Maybe every Python object should have a flag which can be set to prevent introspection -- like the current restricted execution mechanism, but on a per-object basis. Then any object could be used as a capability.
I think the capability folks would object to calling it a capability though. :-)
- Where to store the flag? It probably would cost 4 bytes per object.
- Which attributes are considered introspective?
--Guido van Rossum (home page: http://www.python.org/%7Eguido/)