Exactly what do you see as the required "non-linear extensibility"? These are ultimately requests to a server. Each new extension is coded in that server. There is no value in a client making up its own extensions that are not understood by the server. What is relevant is a server continuing to support clients that have not yet been updated to understand a new format. As I stated in my first post, that problem was solved in ANSI C. Python/JSON is trivial. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.openstack.org/pipermail/openstack/attachments/20120413/62a5aa39/attachment.html>