[Python-Dev] redefining is

[Josiah Carlson]

[snip]

> perhaps two distinct objects.  How can one determine straightforwardly
> whether those objects are members of the same equivalence class?

You were there and helped point out some of the limitations of the
original code I posted, which now has a _straightforward_ recursive
implementation here:
http://mail.python.org/pipermail/python-dev/2004-March/043357.html

It holds up to the equivalence class requirements and is easy to use. As
far as I can tell, it would be relatively straightforward to convert it
into a C implementation and give it some sort of keyword name. Whether
the conversion and keyword makes sense in the future, or whether a
function is sufficient, I'll leave to others.

 - Josiah