W3C home > Mailing lists > Public > www-rdf-calendar@w3.org > December 2003

RE: Syntactic profile of RDFiCal?

From: Danny Ayers <danny666@virgilio.it>
Date: Fri, 19 Dec 2003 13:05:45 +0100
To: "Garret Wilson" <garret@globalmentor.com>, "Libby Miller" <Libby.Miller@bristol.ac.uk>
Cc: <www-rdf-calendar@w3.org>
Message-ID: <BKELLDAGKABIOCHDFDBPEEDBENAA.danny666@virgilio.it>

So DTD & XSD don't sound too promising..! I've seen this stuff talked about
so many times, but I think this is the first time I've read what happens if
you actually try it.

Anyhow, I've no personal experience, but I believe RelaxNG allows a lot of
flexibility not found in XSD - might that be an option?


> -----Original Message-----
> From: www-rdf-calendar-request@w3.org
> [mailto:www-rdf-calendar-request@w3.org]On Behalf Of Garret Wilson
> Sent: 16 December 2003 18:03
> To: Libby Miller
> Cc: www-rdf-calendar@w3.org
> Subject: Re: Syntactic profile of RDFiCal?
> We explored this option for probably over a year with XPackage (
> http://www.xpackage.org/ ) in the Open eBook Forum (OEBF). We had really
> strong pullback in the OEBF against the use of RDF, on the theory that
> (1) we need to get book publishers to adopt OEB, (2) publishers can't
> understand RDF, and therefore (3) we have to use plain XML.
> In the end, after the OEBF's plans for its next version stalled, I
> decided to take out the normative XML Schema version of XPackage
> altogether---it simply wasn't worth the effort. (The above logic forgot
> to figure in that publishers don't understand XML, either.) I left in an
> XML Schema version only for informative purposes.
> * Creating an XSD version of XPackage in many ways negated the benefits
> of RDF.
> * As you mention, if we want collections we *must* require an "ugly"
> rdf:parseType---it's not good enough to just make it a default attribute
> in a DTD.
> * A pure XML version that is RDF-compatible still requires rules for
> processing rdf:about/rdf:resource---unless you intend to make *every*
> resource inline.
> * Extensibility is basically gone, unless you introduce rules about how
> new XML elements can be added to the XML Schema, in ways that are RDF
> compatible. At this point, you're almost creating a separate framework
> that duplicates RDF.
> * With an XSD or DTD version, the pure RDF version would be useless, as
> we would need to support the lowest common denominator. Otherwise, there
> would be both a pure XML version and a pure RDF version, in which case
> who cares if the XML version is RDF-compliant or not if there are two
> versions anyway?
> I could go on and on. At first this sounds like a good idea, but the
> more you try to *work* with it, you realize that it's just a feeble
> attempt to placate those who claim they either (A) don't understand RDF,
> or (B) don't see the need for it. Either of those is a dubious reason to
> begin with, I've come to believe.
> (Is Patrick Stickler on the list? Maybe he can share some of his
> opinions from helping me try to do this with XPackage.)
> Cheers,
> Garret Wilson
> GlobalMentor, Inc.
> Libby Miller wrote:
> >
> > hi,
> >
> > On the IETF calendar mailing list [1] they are currently talking about
> > reviving Xcal, which was an XML DTD for iCalendar. I was wondering if
> > we might want to think about a syntactic profile of RDFiCal, as the RSS
> > 1.0 group did for RSS 1.0 with Leigh Dodd's Schematron schema [2], and
> > as we have been doing in the foaf project, again with Leigh's help [3].
> >
> > There are many disadvantages to doing this, the main one being that with
> > all the RDF toolkits I have seen you can't control the output of the
> > RDF, making a specific syntactic output difficult or awkward to create.
> >
> > Additionally, I think we might have to rethink some of the syntax that
> > is currently outputted by the iCalendar to RDF tools, as it often uses
> > parseType="resource", which can make it difficult to use other
> > namespaces with it, e.g.
> >
> > http://swordfish.rdfweb.org/discovery/2003/09/foafcal/foaficaleg.rdf
> >
> > shows an example of using foaf:Person with attendee. regardless of
> > whether this is the right way to do it, if we use
> >
> > <attendee rdf:parseType='Resource'>
> >
> > in a syntactic profile, then there's no way we can get the foaf:Person
> > tag in there. And that may not be too important for some people who
> > focus on properties, but our foaf experience suggests that many people
> > focus on objects when manipulating foaf files for display (and don't do
> > any inference from the schema).
> >
> > These caveats aside, I think an XML version of iCalendar that could be
> > parsed and used by pure XML tools might be very well recieved, and
> > we've done a lot of the hard work already. It'd be annoying to have
> > another XML format in this space, although we could specify mappings to
> > it if it was created.
> >
> > What do you think?
> >
> > Libby
> >
> >
> > [1] http://www.imc.org/ietf-calendar/mail-archive/msg11885.html
> > [2] http://www.ldodds.com/rss_validator/1.0/
> > [3] http://rdfweb.org/pipermail/rdfweb-dev/2003-August/011890.html (see
> > thread for useful discussion of some of the potential issues)
Received on Friday, 19 December 2003 07:14:09 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 20:14:12 UTC