- From: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
- Date: Wed, 20 Feb 2002 22:59:33 +0000
- To: Pat Hayes <phayes@ai.uwf.edu>
- Cc: w3c-rdfcore-wg@w3.org
At 11:41 AM 2/20/02 -0600, Pat Hayes wrote: >>Oh dear, it's looking as if I seriously dropped the ball on this... >> >>With my CC/PP hat on I don't see the following "long-range" usage is >>supported: >> >> _:SomeClientComponent client-property:dpi "100" . >> >> : >> >> client-property:dpi rdfs:range datatype:number . >> >>i.e. does not define support for idiom B in the datatyping desiderata >>document: >> >> >>http://lists.w3.org/Archives/Public/www-archive/2002Jan/att-0133/00-gk.htm >> >>What also now seriously bothers me is that I can't see how the full >>proposal [1] supports this either. I had earlier convinced myself that >>this was all OK, but now I can't see it. Aaargh! > >No, it definitely does not support it, in fact in its current form it >effectively deprecates it, since literals always denote themselves, and >there is no way to change the meaning of an in-line literal. But I thought >that was what we had all decided to do?? The proposals have been saying >this loud and clear in paragraph 1 from the beginning, and people were >sending me only positive comments, so.... Yeah... I don't know how I missed it... I guess I've been looking at so many proposals over the past couple of weeks I'm just not seeing the wood for the trees. >To fix this, at the very least, you would have to use rdfs:drange instead >of rdfs:range. Right now that would not work either, but I can tweak the >semantics to make it work. But at a cost: we have to allow nonmonotonic >datatyping, in the sense that adding an rdfs:drange assertion *alters* the >interpretation of the in-line idiom. There's no way around that, seems to >me. But maybe we can live with this much nonmonotonicity when considering >datatypes. > >Can I ask y'all for some clarification. Do people want to support BOTH >in-line and bnode forms at the same time? That is, should the following >mean the same thing and be affected in the same way by a drange assertion >on ex:age ??: >(1) >person:Jenny ex:age "10" . >(2) >person:Jenny ex:age _:x . >_:x rdfs:dlex "10" . I think both have their place: (1) is how CC/PP currently works, but (2) provides a more flexible way of modelling going forwards. >As things are at present, (1) means that Jenny's age is a character >string, no matter what else you say, whereas (2) says her age is something >that can be described by a character string, so can be modified by other >datatyping. We can change this, as I say, but only at a cost. I have no problem with that bit ... I just want to be able to say that not all strings are valid here, only those which can represent (in this case) Jenny's age. (It doesn't really matter to CC/PP what the "10" formally denotes, but I don't want to avoid the possible conclusion that person:Jenny ex:age "Humpty Dumpty" is equally meaningful.) Also, I don't think they have to be available for the same property, though they may be needed for different properties in the same graph; e.g. person:Jenny ex:age "10" . person:Jenny ex:weight _:x . _:x xsd:number "10" . (Did you mean to use rdfs:dlex in your example above?) #g ------------------------------------------------------------ Graham Klyne MIMEsweeper Group Strategic Research <http://www.mimesweeper.com> <Graham.Klyne@MIMEsweeper.com>
Received on Wednesday, 20 February 2002 18:16:53 UTC