W3C home > Mailing lists > Public > public-rdfa@w3.org > April 2010

Re: rdf:XMLLiteral and the RDF namespace

From: Ivan Herman <ivan@w3.org>
Date: Thu, 29 Apr 2010 07:28:43 -0400
Cc: Toby Inkster <tai@g5n.co.uk>, Constantine Hondros <Constantine.Hondros@wolterskluwer.com>, "public-rdfa@w3.org Community" <public-rdfa@w3.org>, W3C RDFa WG <public-rdfa-wg@w3.org>
Message-Id: <0466B3A9-95CE-4866-8322-B58559995B90@w3.org>
To: Mark Birbeck <mark.birbeck@webbackplane.com>
(I add the RDFa WG to the cc list, because that discussion should be properly followed and archived as part of the WG list)

On Apr 29, 2010, at 06:16 , Mark Birbeck wrote:

> Hi Ivan,
>>> But now that RDFa 1.1 has a more cohesive story about about CURIEs and
>>> tokens being applied consistently across all of our attributes, we
>>> should consider creating an 'xmlliteral' token to sit alongside
>>> 'next', 'prev', 'license', etc.
>> But this is not only an rdf:XMLLiteral issue, is it?
> That's true, but rdf:XMLLiteral is the only data type that is referred
> to in the processing rules. It does therefore have a special position
> in RDFa.

Formally yes. But we do refer to xsd explicitly all over the place, too... 

>> If the XHTML code contains an explicit
>> @datatype="xsd:integer", this also requires the definition of the xsd prefix. Do you mean
>> that we should define a term for all the XSD datatypes?
> No, I wasn't suggesting that...but now you say it, I don't think it's
> such a bad idea. :)


> At the very least, we should consider defining
> some basic types, such as integers and dates.

Yes, we could think of doing that, indeed. See also below

>> There is quite a load of them, and
>> there is a danger that those terms would clash with terms used elsewhere (remember that
>> we do not have any association that says that a specific term can be used with a specific
>> attribute only...)
> That's true, although I'm not sure what the scenarios would be where
> we clash with tokens that people have defined, such as 'integer',
> 'date', etc.

Maybe true. I should go through all the xsd datatypes to see if there is any danger and I am at WWW right now, with not that much time for checking something like that:-)

(I still have the eery feeling that we may need that extra possibility to restrict a specific term to specific attributes...)

>> We had some discussion about defining default prefixes. One possibility would be to say
>> that prefixes for all standard W3C URIs vocabularies are automatically defined by default,
>> ie, rdf, rdfs, skos, owl, xsd, powder (I may forget some). The inclusion of non-standard
>> prefixes like foaf, dc, or cc, might be more touchy in terms of (social) process, but I do not
>> see any issue with standard w3c vocabularies...
> That's also a way to go, but forgive me for saying that I don't think
> it aims high enough.
> I think we want Microformats-like simplicity in the resulting markup,
> and that means we need to exposed complex features in a simple way.
> With tokens and @vocab, authors can go a long way without having to
> make use of prefix mappings, so I'd like to see us continue in that
> direction.

So a default profile (if we go down that line, that is) could

- include prefixes for standard vocabularies
- include terms for some of the most important datatypes, including XMLLiteral
- maybe, but only maybe, terms for some of the most important rdf/rdfs/owl terms like seeAlso or sameAs

although, I must admit, I am quite weary about the third thing because, well, how would we pick those terms? We do not really have a statistics to rely on... But that important point is that a profile file can include all these in one place



> Regards,
> Mark
> --
> Mark Birbeck, webBackplane
> mark.birbeck@webBackplane.com
> http://webBackplane.com/mark-birbeck
> webBackplane is a trading name of Backplane Ltd. (company number
> 05972288, registered office: 2nd Floor, 69/85 Tabernacle Street,
> London, EC2A 4RR)

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 Thursday, 29 April 2010 11:29:25 UTC

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