- From: Henrik Frystyk Nielsen <frystyk@microsoft.com>
- Date: Thu, 7 Sep 2000 08:35:57 -0700
- To: "Simon St.Laurent" <simonstl@simonstl.com>, <michaelm@netsol.com>
- Cc: <XML-uri@w3.org>
> Abstract concepts don't have to be that airy. Nouns aren't, > for instance, > and the noun to which 'New York' refers changes every second > of every day. 'New York' is an identifier that identifies a fuzzy thing that changes all the time and looks different to all people. At some abstract level, however, we all agree on that it is something that looks like a city on the US east coast. A URI is an identifier that identifiers abstract resources that may change all the time and may look different to different people. What's the difference other than the generalization? > If I describe the namespace URI "http://www.w3.org/1999/xhtml", am I > describing the entity body (a resource, I think) stored at > that address? > Am I describing a 'namespace', something which exists purely in the > abstract? Am I describing (as I think would be intended) > XHTML itself? > We've had very different answers on xml-uri, and I'm not > convinced that the > flaws are on the XML side of the equation. Resources are first class objects - you identify them using URIs. When describing or talking about a resource, you use the URI to refer to that resource. You can never get to the resource - you can get a manifestation of the resource - for example by performing an HTTP GET request on it. A resource can have any number of manifestations - think of each manifestation as a snapshot of a living thing: you can take as many snapshots you like - some may be the same and some may not. > The URI opens possibilities, but it provides no way to choose > among those > possibilities. This isn't a problem peculiar to Namespaces > in XML, either. > It arises any time you need to describe a resource or a URI, > since the two > are effectively blurred by the practices enshrined in RFC 2396. I don't believe it mentions anywhere that you are describing URIs because that wouldn't make sense. > On a more mechanical level, I think the xml-uri discussions > have made it > clear that rules for comparing URIs are broken at worst, > contested at best. > Providing a baseline comparison that could be used across > schemes - even > at the cost of false negatives - would have made all of this > much easier. A baseline comparison is exactly what RFC 2396 defines - you keep saying this - what is it that you don't see defined? Henrik
Received on Thursday, 7 September 2000 11:35:24 UTC