- From: Graham Klyne <gk@ninebynine.org>
- Date: Wed, 10 Sep 2003 08:54:12 +0100
- To: Brian McBride <bwm@hplb.hpl.hp.com>
- Cc: rdf core <w3c-rdfcore-wg@w3.org>, Martin Duerst <duerst@w3.org>, Richard Ishida <ishida@w3.org>, i18n <w3c-i18n-ig@w3.org>
At 17:15 09/09/03 +0100, Brian McBride wrote: >Graham Klyne wrote: >>Brian, >>As I understand it, this proposal > >Its not a proposal - at least I'm not making a proposal. OK, I misinterpreted you. So, to be clear, what follows is on the understanding that we are exploring alternative designs, not proposing them... (I have raised non-exploratory points arising in separate messages.) > could break existing RDF data. E.g. >> <rdf:Description> >> <eg:prop>foo < bar</eg:prop> >> </rdf:Description> >>would no longer be valid RDF. > >It would remain legal rdf/xml. Ah, this depends on different understanding of the current RDF/XML syntax; I've raised this as an issue for clarification in a separate message. [...] >>Then: >><rdf:Description> >> <eg:prop>foo <br /> bar</eg:prop> >></rdf:Description >>parses to: >> _:a eg:prop "foo <br /> bar" . >>and >> <rdf:Description> >> <eg:prop rdf:parseType="Literal"><br /></eg:prop> >> </rdf:Description> >>parses to: >> _:a eg:prop "foo <br></br> bar" . > >Interesting - similar idea - treat all literals as XML but you've got it a >different way round somehow. Not quite: treat all literals as plain text, which MAY be used to encode XML. That's the "different way round". Yours, I think, is to treat all literals as XML which MAY be used to encode plain text. >How do we distinguish between text and markup e.g. how to I represent the >book title I don't. At least, not as part of the literal itself. The property used would determine that. So, considering: _:a eg:title "The <b><b></b> Element Considered Harmful" . the property eg:title would relate the plain text strings used above to the rich text you described: > The <b> Element Considered Harmful > >where "<b>" is in bold? However, a different property: _:a eg:rel "foo < big" . might relate the plain text given to an expression that performs a comparison. [...] >Hmmm, but you would allow "<" as a legal rdf literal lexical form and the >other design didn't. Yes. I have always understood RDF to be this way. Indeed, I have real RDF (N3) data that contains *HTML* (not XML) markup in literal values. I'd be most surprised if I'm alone in this. > That means we can't treat all rdf literals as xml. So how do we know > when they are and when they are not? See above. There's no absolute rule, and I don't see why there should be. >>I think there remains a question: can parseType=Literal be used in >>conjunction with rdf:datatype=...? > >Not in the design I described, but in yours ... > > I see no reason why not. Then the >>current functionality of XML literals is possible without making it part >>of the RDF core specification; e.g. >> <eg:prop rdf:parseType="Literal" rdf:datatype="foo:XMLLiteral"> >> The <em>best</em> solution? >> </eg:prop> >>(Note: I expect that rdf:datatype continues to ignore language >>information, so the above example would not be sensitive to language tagging.) >>I think this approach has similar advantages to what you propose, without >>some of the disadvantages, also separates XML syntax issues from datatype >>issues, which I think is a distinct improvement, and remains fully >>backward compatible with (my understanding of) existing RDF. > >The backward compatibility is certainly a plus. Just a little ;-) #g ------------ Graham Klyne GK@NineByNine.org
Received on Wednesday, 10 September 2003 04:07:44 UTC