- From: <noah_mendelsohn@us.ibm.com>
- Date: Tue, 22 Mar 2005 14:47:10 -0500
- To: Dan Connolly <connolly@w3.org>
- Cc: Chris Lilley <chris@w3.org>, "Henry S. Thompson" <ht@inf.ed.ac.uk>, www-tag <www-tag@w3.org>
Dan Connolly writes: > I have thought of it as implicit in the spec too, > but it's clearly too implicit. I hope to clarify > soon... > There's a relevant section... in the editor's > draft, at least... > http://www.w3.org/2004/01/rdxh/spec#ns-bind Cool! Am I right in suggesting that this is in part making good on the promise of Cambridge Communiqué which states [1]: "The extension mechanism should be appropriate for use to incorporate declarations ("mapping declarations") to aid the construction of application-oriented data structures (e.g. ones implementing the RDF model) as part of the schema-validation and XML infoset construction process. This facility should not be exclusive to RDF, but should also be useable to guide the construction of data structures conforming to other data models, e.g. UML." Actually, the Communiqué focussed quite a bit on putting the mapping hooks into the XML Schema for a namespace, and that seems to be exactly what's shown at [2]. So, it took 5 years, big deal! Maybe Dan's historical review at [3] should mention the Communiqué, the hooks left in the XML schema design, and the exploitation of those hooks by GRDDL? On a barely related subject: I'm tempted to ask how central the .xsl document really should be in defining the transformation. On the one hand, it obviously is. On the other, it seems to me that XSL is in some ways too high overhead to use in some of the higher performance situations where you'll want to do these mappings. Try to import 100,000 XML documents into and RDF database; running XSL 100,000 times isn't going to help if all you're doing is extracting some simple metadata about authors and creation dates. What I'm struggling to articulate is whether there should be some sense that the URI in the GRDDL should be for the transformation in the abstract, with the xsl viewed just as a representation of that transformation. Thus, we might emphasis that it's not running the .xsl per-se that's mandated by GRDDL, but implementating the correct transform. I don't know whether there are observable differences in these two views, but I think the philosphical implications are somewhat different. For example, I could invent a transform URI and document it in English or French. You or I could write C code to implement the transform. Maybe or maybe not someone would go to the trouble of offering an XSL representation of the transform, retrievable at the URI, as well. This idea seems closely related to but not quite the same as the Standard GRDDL library mentioned in Dan's note. Does this make any sense? Anyway, now that I've finally grok'd GRDDL, it looks like really nice, and more to the point, I like Dan's note at [3]. Noah [1] http://www.w3.org/TR/1999/NOTE-schema-arch-19991007#observations [2] http://www.w3.org/2003/g/po-ex [3] http://www.w3.org/2004/01/rdxh/specbg.html -------------------------------------- Noah Mendelsohn IBM Corporation One Rogers Street Cambridge, MA 02142 1-617-693-4036 --------------------------------------
Received on Tuesday, 22 March 2005 19:48:06 UTC