- From: David G. Durand <david.durand@prov.ingenta.com>
- Date: Mon, 11 Nov 2002 14:55:25 -0500
- To: www-xml-linking-comments@w3.org
- Cc: fielding@apache.org
Roy Fielding wrote: >The interpretation of fragment identifiers is media-type specific. >That does not mean that it is a good idea to define the format of >a fragment differently for every media type. Allowing the same >identifier to apply to multiple media types isn't always possible, >but it is desirable except in those very rare situations >where the user actually intends to identify a specific XML element >(as opposed to the content encapsulated by that element). Which can be regarded as a good support for the fact that the proposed framework supports "bare names" as an addressing mode, defined to work in the most natural way for XML documents. I'd argue that the W3C framework explicitly supports the case that you are worried about (one where the media type of a resolution is unpredictable), while also supporting the important case of more-precise addressing when the media types _are_ more predictable. the W3C has also made no recommendation to the IETF at this point about whether the more-complex XPointer pointer scheme should be optional, recommended, or required. So at least part of your objection seems to be to a proposal that has not yet been made, and may never be made. I personally don't favor making the most-complex pointer schemes mandatory for applications. I think that the notion of schemes itself is actually very good, as can be judged from the fact that people who are not fans of the XPointer scheme are already proposing alternate schemes in its place. The fallback semantics of the XPointer framework provide a nice way to deal with the uncertainty inherent in having a per-media-type addressing syntax that must be packaged along with pointers (URI references) that may return data conforming to a number of media types. Without such a scheme, it's very hard to create URI fragments because any proposal must work across an unbounded number of media types. Adopting this as a practical principle, furthermore, means that no media type can allow any addressing modes that are unique. You may thin XPointers are not an ideal solution for XML documents, but the same arguments would prevent indexing multimedia presentations by time code, or spatial extent, because those addressing modes would not be valid for other media types. -- David -- David G. Durand VP, Software Architecture 12 Bassett St. Providence RI, 02903-4628 USA T: +1 401-331-2014 x111 T: +1 401-935-5317 Mobile E: david.durand@ingenta.com
Received on Monday, 11 November 2002 14:58:17 UTC