- From: Miles Sabin <miles@milessabin.com>
- Date: Tue, 3 Dec 2002 11:32:18 +0000
- To: www-tag@w3.org
Larry Masinter wrote, > I think at the root of many of the difficulties in this discussion is > what seems like an assumption that there is (or should be) only one > notion of "equivalence" for URIs. > > But among the set of all possible strings (sequences of characters), > there are many different equivalence relationships. <snip/> I think this is exactly right. > And it would be helpful for applications that use a fine granularity > equivalence relationship to avoid the situation where two identifiers > that are equivalent under some relationships are used differently, > e.g., mandate that once a namespace name is assigned, no other string, > equivalent under coarser rules, should also be used as a namespace > name. This too. To spell it out a bit more, the problem here is that we have the same string functioning in two roles (as a namespace identifier, as a resource identifier), where each role implies a different equivalence relation. To illustrate, <foo:wibble xmlns:foo="http://a/b/c/%7A" xmlns:bar="http://a:80/x/../b/c/%7a"> </foo:wibble> Applying the current namespace identifier equivalence relation, foo and bar are distinct namespaces. However, applying the RFC 2396/2616 rules the two are equivalent and an attempt to retrieve a namespace document will have the same result in both cases. If the two namespaces really are distinct that seems wrong. So if namespace identifiers _are_ to be used for the retrieval of namespace documents there doesn't seem to be much option but to use RFC 2396 + scheme-specific rules for the namespace identifier equivalence relation too ... which would be unfortunate IMO. Cheers, Miles
Received on Tuesday, 3 December 2002 06:32:52 UTC