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Re: @profile is wrong solution for indicating that RDFa is present

From: Mark Birbeck <mark.birbeck@formsPlayer.com>
Date: Mon, 10 Dec 2007 16:31:06 +0000
Message-ID: <a707f8300712100831iefc1248jfad9c4fb4787380d@mail.gmail.com>
To: "Simone Onofri" <simone.onofri@gmail.com>
Cc: "W3C RDFa task force" <public-rdf-in-xhtml-tf@w3.org>

Hi Simone,

Well, to be clear on GRDDL, it doesn't just use @profile; it says that
the document retrieved from the URL in @profile should contain
indications of a transformation. But it does this because it is
piggy-backing the 'profile definition' that an HTML author may have
already provided, which is in keeping with normal HTML behaviour. So I
might create a 'profile definition' for the hCard microformat, and add
it to @profile, and all GRDDL is doing is saying that this external
document could *additionally* carry a link to an XSLT document.

However, to use this mechanism for RDFa is to put the cart before the
horse; if all we're interested in is the XSLT for GRDDLing, we're
effectively creating an 'empty' taxonomy to carry this information.
This won't be the first time I'm accused of pedantry, I'm sure :) but
we've just spent 4 years discussing whether this or that attribute
could legitimately have this or that meaning, and it doesn't feel
right to me to now say 'let's use @profile to indicate

But as it happens, there might be a better solution anyway; just as
GRDDL piggy-backs 'profile definition' documents to obtain a link to
an associated XSLT, so too it can piggy-back XML namespace documents.
So I would prefer to see a solution that leverages that in some way.
I'm not quite sure how yet--can we leverage the XHTML namespace? do we
need a new one?--but I do feel it is worth discussing.

Another way of doing it that works in both XHTML and HTML is to use
@rel="transformation". This would put the power into the hands of the

By the way, I think we should try to solve this problem for XHTML
first, and leave HTML for later. We will have a number of other issues
to tackle to get HTML support, so we might as well leave it to one
side for now.



On 10/12/2007, Simone Onofri <simone.onofri@gmail.com> wrote:
> Dear Mark,
> Your mail presents a lot of interesting points and inspiration. So
> GRDDL choose @profile, and also Danny can explain it - I remember also
> the proposal of XHTML WG to use @rel on meta (but in this case also
> meta in on the head).
> Actually, in this moment I'm writing, I'm according to Ivan to keep
> @profile is a fine idea.
> But I'm also thinking for another trigger - and maybe fine that can
> coexist with @profile. I like @xmlns but I note that cannot be really
> compatible with HTML (I'm not happy to do HTML, I love XHTML of course
> but we may consider also for it). So another thing is for validation
> by HTML and RDF validator both, that cannot be excluded.
> Any ideas to get a brainstorm on mailing list?
> Cheers,
> Simone
> On Dec 10, 2007 4:17 PM, Mark Birbeck <mark.birbeck@formsplayer.com> wrote:
> >
> > Hello all,
> >
> > During the course of writing a blog post [1] in response to one from
> > Danny Ayers [2], I realised that the use of @profile to indicate the
> > presence of RDFa is not really in keeping with the spirit of the
> > attribute in HTML.
> >
> > Although not clearly defined, @profile is generally used to provide
> > information to a user agent about how it might interpret values in
> > <meta> and <link>. This is used to good effect in microformats and
> > GRDDL, and both uses of @profile are well within the spirit of how
> > @profile is defined in HTML.
> >
> > But RDFa already has a way to disambiguate values, based on the use of
> > CURIEs and prefix mappings. At the moment we don't use @profile to
> > indicate taxonomies, but @xmlns. What we do instead is provide a fixed
> > value for @profile that is supposed to indicate the presence of RDFa,
> > but that is not providing a 'profile' in the usual sense--a set of
> > terms that help with interpretation--but is simply using @profile to
> > set a 'boolean' flag to true.
> >
> > I feel this overloads @profile in a way that might confuse people
> > ("where is the RDFa taxonomy defined by this profile?"), and would
> > suggest we look for an alternative means of setting this 'flag'. There
> > are many ways we could do this, but for now I wanted to just flag this
> > up as an issue.
> >
> > Regards,
> >
> > Mark
> >
> > [1] <http://internet-apps.blogspot.com/2007/12/rdfa-profile-and-following-your-nose.html>
> >
> > [2] <http://dannyayers.com/2007/12/08/another-little-abstraction>
> >
> > --
> >   Mark Birbeck, formsPlayer
> >
> >   mark.birbeck@formsPlayer.com | +44 (0) 20 7689 9232
> >   http://www.formsPlayer.com | http://internet-apps.blogspot.com
> >
> >   standards. innovation.
> >
> >
> --
> Simone Onofri
> http://www.siatec.net/

  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, 10 December 2007 16:31:22 UTC

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