- From: <noah_mendelsohn@us.ibm.com>
- Date: Sat, 28 Aug 2004 21:07:22 -0400
- To: Rick Jelliffe <ricko@allette.com.au>
- Cc: Dare Obasanjo <dareo@microsoft.com>, www-tag@w3.org
Rick Jeliffe writes: > At the moment, when you derive a new schema, you > cannot really create a new namespace for the > pragmatic reason that stylesheets and namespace-aware > software breaks. Ignoring for the moment the question of whether leveraging a namespace hierarchy is an inappropriate break with the desire to treat URIs as opaque where practical, I agree that hierarchies would help with compatible consumption of evolving versions by namespace-aware tools. That's potentially important. The problem I see is that it doesn't help at all with another show stopper: I believe that any versioning architecture must scale for use over tens, perhaps hundreds of revisions. In part because the instance syntax for namespace prefixes is unaware of any hierarchy, an instance document would presumably have to define and track prefixes for each level of the hiearchy actually used. Perhaps worse, the user would have to remember which constructs were introduced by which version. It seems to me that the proposal scales in practice only if we are willing to have prefix bindings in instances that are themselves aware of the hierarchy, Maybe you had this in mind, but your note referred only to awareness of the hierarchy in the schema language and other namespace-aware tools. Am I missing something? Thanks. I do agree that an opportunity was missed to consider the admittedly very thorny problem of versioning when namespaces were being developed. I understand that was a painful enough process in any case, but I agree with your intuition that tying versioning to namespaces would have been a fruitful angle to explorer. FWIW, and as Matt Fuchs has often pointed out, what XML Schema calls local scoping might well have been easier to do clearly with, e.g., some facility for signaling that each element implied or was associated with its own default namespace. We never worked out the details, but there too the intuition seems right to me. -------------------------------------- Noah Mendelsohn IBM Corporation One Rogers Street Cambridge, MA 02142 1-617-693-4036 --------------------------------------
Received on Sunday, 29 August 2004 01:08:58 UTC