Ordered Sets

[pataphor]

On Mon, 30 Mar 2009 19:57:39 -0700 (PDT)
Alex_Gaynor <alex.gaynor at gmail.com> wrote:

> I really like the Ordered Set class(I've been thinking about one ever
> since ordered dict hit the std lib), is there any argument against
> adding one to the collections module?  I'd be willing to write a PEP
> up for it.

Suppose the implementation would use a circular linked list. Then the
iteration could start from any point, the thing is symmetric after all.
But this would also mean we could add items to the left of that new
starting point, since that would now be the 'end' of the circle. This
is something different from merely remembering insertion order. How do
you feel about that?

P.