Proposed implementation for an Ordered Dictionary

[Raymond Hettinger]

[Paul Rubin]
> Ehh, I guess I'm not surprised at the slowdown and extra complexity
> from the second dict.  Oh well.  If the module really turns out to be
> really used a lot, another (messy) approach would be to write a C
> extension that uses a doubly linked list some day.

That seems like an ideal implementation to me.

  O(1): appending, popping, searching, and deletion
  O(n): traversal

Raymond