- From: Sean B. Palmer <sean@mysterylights.com>
- Date: Wed, 22 Aug 2001 14:36:59 +0100
- To: <Patrick.Stickler@nokia.com>
- Cc: <www-rdf-interest@w3.org>, <uri@w3.org>
> Hmmmm.... do we need then to use DAML equivalence > constructs for basic RDF?! E.g. > > <qn:{http://description.org/schema/}Creator> > daml:equivalentTo > <qn:{http://description.org/schema/}@Creator> . No, because those QNames are in RDF, and RDF processors handle them by concatenating them and forming a URI. The XML Namespace specification defines a difference between the QNames, but it doesn't tell you how to handle them. The RDF specification comes in and tells people what to do with the QNames. It tells one to concatenate the QNames togther minus partition information, to form a URI. There's no problem with that, except there's no way to identify a QName as a first class object without some extra properties, or a new URI scheme. So there's no particular need to map every QName in XML RDF to your URI scheme - to do so would be silly - but it doesn't stop people using it. In other words, you've accomplished all that you want to accomplish simply by inventing this URI scheme. If you force people to adopt it *instead* of the concatenation mechanism in XML RDF, then you'll form an utter mess, because the Semantic Web deals with URIs, and not just QNames. Using the concatenation mechanism is an excellent and quick way to form those URIs out of QNames. Your URI scheme is good (saves the need for even decentralized QName properties), and I'm sure that I will be recommending it to anyone that needs to map between QNames, define them using RDF, or whatever. WAI PF have been looking for something like this for quite a while. But RDF uses URIs and not QNames, and now that you've come up with representing an XML QName (i.e. with all the details preserved as in the XML namespace specification) as a URI, that's fine. Now, there are only two errors with your URI scheme. The first is that the characters "{" and "}" are disallowed in URIs per section 2.4.3 of RFC 2396. This can be easily gotten round by using "(" and ")" instead, e.g.:- qn:(http://www.w3.org/1999/xhtml)title that's a shame because I often use "{}" for QNames. The problem is more difficult. Namespaces are actually URI References, and yet you need to include them in a URI scheme. URI References with a "#" aren't allowed in URIs. In other words, the following is illegal:- qn:(http://infomesh.net/2001/08/example#)myElement Because the "#" character is also disallowed by section 2.4.3 of RFC 2396. Perhaps you can just %HH encode it? qn:(http://infomesh.net/2001/08/example%23)myElement Which *should* be O.K., but it needs further discussion. Note that if your namespace ends (or contains) a "%23", then you can escape the "%" to use that; i.e. "%2523". qn = 'qn:' '(' absoluteURIexc [ '%23' fragment ] ')' ( elem | glob | per ) elem = NCName glob = '@' NCName per = NCName '@' NCname BTW, I know that you've only just invented this scheme and so on, but once people on uri@w3.org have discussed it, could you create an Internet Draft of it, and send it to the IETF for consideration? Cheers. -- Kindest Regards, Sean B. Palmer @prefix : <http://webns.net/roughterms/> . :Sean :hasHomepage <http://purl.org/net/sbp/> .
Received on Wednesday, 22 August 2001 09:36:59 UTC