Re: Proposal for an additional 'link type' for rdf:type

Hi Mark,

you beat me to it. :) I was just writing a response very close to your
thinking. But I placed the stuff in the root element instead.. Would
that not validate? (A note also: isn't @instanceof supposed to take
only CURIE values? If so, you don't need/cannot use brackets in it,
right?)

I just paste my response here; I think it pretty much supports your reasoning:

I think I'd like if this:

    <html xmlns="http://www.w3.org/1999/xhtml"
          xmlns:foaf="http://xmlns.com/foaf/0.1/"
          instanceof="foaf:PersonalProfileDocument">
        <head>
            <title>My profile</title>
        </head>
        ...

would be enough. Though it seems (to the in the *trained* eye IMHO)
that this generates a bnode for the entire content, I'd like to think
that the root element provides ("captures") the current resource,
meaning that its start tag has an implicit @about="" in it. Hence
making the above mean exactly the same as:

    <html xmlns="http://www.w3.org/1999/xhtml"
          xmlns:foaf="http://xmlns.com/foaf/0.1/"
          about=""
          instanceof="foaf:PersonalProfileDocument">
        <head>
            <title>My profile</title>
        </head>
        ...

, which does achieve what we're after..

Or is this just a stretch, making @instanceof (seem to) behave
differently on the root element? If so, is the latter so bad it really
calls for something more?

Best regards,
Niklas



On 10/1/07, Mark Birbeck <mark.birbeck@formsplayer.com> wrote:
>
> Hi Ivan,
>
> Thanks for forcing me to think it through more. :) I think that there
> is probably a neat way to write this using current mark-up, although
> working through it has highlighted something that I think we need to
> clarify.
>
> Sticking purely with trying to make the rdf:type use-case easier
> (i.e., rather than the general use of RDF/RDFS namespaces), there is
> nothing to stop us doing this:
>
>   <html
>    xmlns="http://www.w3.org/1999/xhtml"
>    xmlns:foaf="http://xmlns.com/foaf/0.1/"
>   >
>     <head>
>       <title>My profile</title>
>       <link about="" instanceof="[foaf:PersonalProfileDocument]" />
>     </head>
>      .
>      .
>      .
>   </html>
>
> It looks odd, since there is no @rel or @rev, but it is allowed by the
> syntax. But once you go down that route, you might as well use the
> following, which is also allowed by the syntax, and is probably much
> clearer in terms of intent:
>
>   <html
>    xmlns="http://www.w3.org/1999/xhtml"
>    xmlns:foaf="http://xmlns.com/foaf/0.1/"
>   >
>     <head about="" instanceof="[foaf:PersonalProfileDocument]">
>       <title>My profile</title>
>     </head>
>      .
>      .
>      .
>   </html>
>
> Which brings us to the point that I think we need to clarify; what if
> I wrote this:
>
>     <head instanceof="[foaf:PersonalProfileDocument]">
>       <title>My profile</title>
>       <meta property="dc:creator" content="John Doe" />
>     </head>
>
> In our current rules this would generate a new bnode for <head>, and
> the dc:creator property would apply to that, which I don't think is
> desirable. But if we were to make it a little more explicit that the
> 'identity' of <head> is the current document, unless overridden
> *explicitly* by @about, then my rdf:type use-case falls out quite
> neatly to the following mark-up:
>
>   <html
>    xmlns="http://www.w3.org/1999/xhtml"
>    xmlns:foaf="http://xmlns.com/foaf/0.1/"
>   >
>     <head instanceof="[foaf:PersonalProfileDocument]">
>       <title>My profile</title>
>     </head>
>       .
>       .
>      .
>   </html>
>
> I think that's actually quite clear from the point of view of what an
> author is trying to do, and it has also exposed that we might need to
> say a little more about what happens with the <head> element.
>
> What do you think?
>
> Regards,
>
> Mark
>
>
>
> On 01/10/2007, Ivan Herman <ivan@w3.org> wrote:
> > Hm. You won't like me, but I am not sure I like it:-)
> >
> > Though is see the rationale, we create some sort of an odd case. At the
> > moment the agreement is that a @rel value without a CURIE prefix is
> > considered to be in
> >
> > http://www.w3.org/1999/xhtml/vocab#
> >
> > and that is it. This is a very clear and easy-to-follow rule. What you
> > propose is that, well, this is true, _except_ for the value of
> > instanceof that behaves differently. I am not sure it is good if we
> > begin to introduce such exceptions.
> >
> > Or did I misunderstand you?
> >
> > A possible way out is to say that the 'rdf:' prefix (and probably the
> > 'rdfs:' prefix) will always be added to the result of an RDFa processor
> > with the usual values. This is not very nice either, but I would prefer
> > to solve your problem that way...
> >
> >
> > Ivan
> >
> > Mark Birbeck wrote:
> > > Hello all,
> > >
> > > Whilst considering RDFa use in the wild, it occurred to me that
> > > constructs like the following would almost certainly become quite
> > > common:
> > >
> > >   <html
> > >    xmlns="http://www.w3.org/1999/xhtml"
> > >    xmlns:foaf="http://xmlns.com/foaf/0.1/"
> > >    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
> > >   >
> > >     <head>
> > >       <title>My profile</title>
> > >       <link rel="rdf:type" resource="[foaf:PersonalProfileDocument]" />
> > >     </head>
> > >     .
> > >     .
> > >     .
> > >   </html>
> > >
> > > If the author wants to avoid having to include the RDF namespace, they
> > > would have to change their mark-up to look something like this:
> > >
> > >   <html
> > >    xmlns="http://www.w3.org/1999/xhtml"
> > >    xmlns:foaf="http://xmlns.com/foaf/0.1/"
> > >   >
> > >     <head>
> > >       <title>My profile</title>
> > >     </head>
> > >     <body about="" instanceof="foaf:PersonalProfileDocument">
> > >       .
> > >       .
> > >       .
> > >     </body>
> > >   </html>
> > >
> > > However, if we added an additional link type, such as 'a' or
> > > 'instanceof', we could also allow the following mark-up:
> > >
> > >   <html
> > >    xmlns="http://www.w3.org/1999/xhtml"
> > >    xmlns:foaf="http://xmlns.com/foaf/0.1/"
> > >   >
> > >     <head>
> > >       <title>My profile</title>
> > >       <link rel="instanceof" resource="[foaf:PersonalProfileDocument]" />
> > >     </head>
> > >     .
> > >     .
> > >     .
> > >   </html>
> > >
> > > This avoids the need to declare the RDF namespace, and keeps the
> > > metadata in the head of the document which seems more appropriate for
> > > this particular kind of statement.
> > >
> > > Regards,
> > >
> > > Mark
> > >
> > >
> >
> > --
> >
> > Ivan Herman, W3C Semantic Web Activity Lead
> > Home: http://www.w3.org/People/Ivan/
> > PGP Key: http://www.ivan-herman.net/pgpkey.html
> > FOAF: http://www.ivan-herman.net/foaf.rdf
> >
> >
>
>
> --
>   Mark Birbeck, formsPlayer
>
>   mark.birbeck@formsPlayer.com | +44 (0) 20 7689 9232
>   http://www.formsPlayer.com | http://internet-apps.blogspot.com
>
>   standards. innovation.
>
>

Received on Monday, 1 October 2007 12:18:43 UTC