- From: Dan Brickley <danbri@w3.org>
- Date: Thu, 6 Nov 2003 06:20:30 -0500
- To: Dave Beckett <dave.beckett@bristol.ac.uk>
- Cc: Graham Klyne <gk@ninebynine.org>, Jeremy Carroll <jjc@hplb.hpl.hp.com>, w3c-rdfcore-wg <w3c-rdfcore-wg@w3.org>
Perhaps the simplest clarification that would fix rdf:Alt is to make it clear that it needs to be used with supporting vocabulary, ie. this is a modelling level component of RDF, something that can be used, rather than something down deep in the RDF infrastructure. ie. I can't write <foaf:Person> <foaf:workplaceHomepage> <rdf:Alt> <rdf:li> <foaf:Document rdf:about="http://www.w3.org/"/> </rdf:li> <rdf:li> <foaf:Document rdf:about="http://ilrt.org/"/> </rdf:li> </rdf:Alt> </foaf:workplaceHomepage> </foaf:Person> ...and to expect it "just work" by the power of RDF. If foaf:Document and rdf:Alt are disjoint (which FOAF could state in OWL) this would be false, since foaf:workplaceHomepage has a range of foaf:Document. I guess the best practice guideline is that rdf:Alt is only useful when used alongside RDF vocabulary explicitly created to work with it. eg. a foaf:workplaceHomepageAlt property with rdf:Alt as its value would be OK. Would the primer be a natural home for something like this? Or maybe just shove it in the ESW wiki...? Dan * Dave Beckett <dave.beckett@bristol.ac.uk> [2003-11-06 11:09+0000] > > On Thu, 06 Nov 2003 10:41:44 +0000, Graham Klyne <gk@ninebynine.org> wrote: > > > > > At this stage of the game, if we choose to make any substantive changes in > > response to these comments I think they should be simple excisions. > > > > I could see removing the preference for the first Alt as an excision. Or > > simply removing Alt all together? There's nothing special about rdf:Alt > > that users couldn't define their own vocabulary for it. (Personally, I > > think Alt is rather like the human appendix: of little practical value and > > a potential source of inflammation.) > > We already decided not to change RDF containers, I don't see any point > doing that further now - it is not a critical change. > > RDF Semantics says on Alt: > "things of type rdf:Alt are considered to represent a collection of > alternatives, possibly with a preference ordering" > -- 3.2.2 http://www.w3.org/TR/rdf-mt/#Containers > > RDF Concepts & AS WD says nothing. > RDF/XML WD deals with the syntax use only. > > RDF Primer does mention the prefered value rdf:_1 > > "An Alt container is intended to have at least one member, identified by > the property rdf:_1. This member is intended to be considered as the > default or preferred value. Other than the member identified as rdf:_1, > the order of the remaining elements is not significant." > -- just after http://www.w3.org/TR/rdf-primer/#example15 > > Maybe there is some work to make these a little more aligned. > > Dave
Received on Thursday, 6 November 2003 06:20:55 UTC