- From: Andy Seaborne <andy.seaborne@epimorphics.com>
- Date: Mon, 07 Mar 2011 08:40:11 +0000
- To: Ivan Herman <ivan@w3.org>
- CC: Steve Harris <steve.harris@garlik.com>, Sandro Hawke <sandro@w3.org>, Pat Hayes <phayes@ihmc.us>, RDF Working Group WG <public-rdf-wg@w3.org>
rdf:PlainLiteral should never appear in RDF as a datatype. The literal should have been written in normal RDF form. http://www.w3.org/TR/rdf-plain-literal/ [[ Sec 4: Therefore, typed literals with rdf:PlainLiteral as the datatype are considered by this specification to be not valid in syntaxes for RDF graphs or SPARQL. To implement this design and provide this interoperability, applications that employ this datatype MUST use plain literals (instead of rdf:PlainLiteral typed literals) whenever a syntax for plain literals is provided, such as in existing syntaxes for RDF graphs and SPARQL results. ]] Andy On 07/03/11 05:46, Ivan Herman wrote: > > On Mar 6, 2011, at 09:12 , Steve Harris wrote: > [snip] >> >>> (FWIW, offhand, I think this is a better solution than the one in my >>> email of 2 minutes ago.) >>> >>> (I don't think rdf:PlainLiteral is a problem. It was designed not to >>> be, and I haven't heard any reports of it turning out to be. It's just a >>> way to express plain literals in systems like RIF and OWL 2 that don't >>> have native plain literals. It doesn't manifest in systems like RDF and >>> SPARQL that do have native plain literals.) >> >> I'm not really clear on what rdf:PLainLiteral does, or is for, so I don't really have an opinion. >> > > My own elevator pitch: if I want do to any time of datatype reasoning (in RDFS, OWL, or RIF) with a literal that has language tags, then I need a datatype that has language tags. xsd:string does not have languag tags, and RDF's plain literal is not a datatype. Hence rdf:PlainLiteral that is a datatype for strings with language tags. > >> Is it likely to encounter rdf:PlainLiteral in the wild? I don't off-hand know of any RDF parsers that do anything special with it. > > The answer is probably not really. But if RIF-like or OWL-like reasoning (and that includes OWL RL in this case, too, ie, a relatively simple OWL reasoning layer) is used on multilingual data, then rdf:PlainLiteral (or something like that) becomes unavoidable. > > The more generic fact is: my feeling is that RDF data (or vocabularies) in the wild is still dominated by English data (although I do not have exact measure). That is a separate problem but obviously related to the issue of rdf:PlainLiteral and its occurrence. > > Ivan > > >> >> - Steve >> >> -- >> Steve Harris, CTO, Garlik Limited >> 1-3 Halford Road, Richmond, TW10 6AW, UK >> +44 20 8439 8203 http://www.garlik.com/ >> Registered in England and Wales 535 7233 VAT # 849 0517 11 >> Registered office: Thames House, Portsmouth Road, Esher, Surrey, KT10 9AD >> >> > > > ---- > Ivan Herman, W3C Semantic Web Activity Lead > Home: http://www.w3.org/People/Ivan/ > mobile: +31-641044153 > PGP Key: http://www.ivan-herman.net/pgpkey.html > FOAF: http://www.ivan-herman.net/foaf.rdf > > > > >
Received on Monday, 7 March 2011 08:40:50 UTC