W3C home > Mailing lists > Public > public-rdf-in-xhtml-tf@w3.org > June 2007

Re: Validation Update: success!

From: Ben Adida <ben@adida.net>
Date: Mon, 25 Jun 2007 16:53:03 -0700
Message-ID: <4680555F.2090809@adida.net>
To: Keith Alexander <k.j.w.alexander@gmail.com>
CC: CÚdric Mesnage <cedric.mesnage@lu.unisi.ch>, RDFa <public-rdf-in-xhtml-tf@w3.org>

Keith Alexander wrote:
> The problem is quality and not quantity. If you parse in a different way
> than I intended, you risk getting factually and/or syntactically
> incorrect RDF. So it's important that it be clear whether I am
> publishing bad RDF, or you are interpreting it badly.

Okay, but if you use the RDFa DTD, then you clearly intend RDFa, right?
Otherwise, you're saying that @profile is the only way to provide
semantics. That seems a bit too GRDDL-centric a view. See below: I think
existing HTML DTDs provide plenty of semantics already.

> Not can't, but doesn't in it's current incarnation (so I think anyway),
> because it doesn't say anything about RDF in the HTML spec. So it seems
> unfair on HTML authors to change the rules on them after the fact. As a
> developer, you are always free to screen-scrape of course, but I don't
> think the semantics are built in. I don't think you could get a lot
> further than <document> html:title /html/head/title/text() without
> running into trouble.

Ah, you and DanC agree on this :) I am thoroughly confused by this
concept that since the HTML spec doesn't say RDF, then it can never
imply RDF triples. HTML implies a whole bunch of semantics. This
semantic data can be expressed using RDF. It seems we all agree that

<document> html:title /html/head/title/text()

is clearly implied by HTML... who cares that that is RDF? It's abstract
semantics, which happens to be representable as RDF. Could you really
argue that the above triple is *not* implied by an HTML document's title?

In fact, in HTML, there's the title attribute, but there's also all the
reserved keywords for REL and REV, the META and LINK attributes in the
HEAD, the CLASS attributes (which really are meant for semantic markup).
The semantics of all of these things can only be determined by following
your nose to the HTML DTD spec.

[...]

> 1/ It might not be the same triples - and some of them might be wrong.
> 2/ In this case, two rdf:IDs with the same value is syntactically
> incorrect RDF/XML.
> 
> I don't think the profile and the DTD are really (or ought to be) doing
> the same thing  - the DTD is defining the syntax, but how the triples
> are generated is defined by the profile. The DTD can let you determine
> if the document is valid against that DTD, but can it define the triples
> generation rules and tell you if the RDF that you can derive from the
> document according to them, is valid?
> 
> I'm inclined to agree with Dan's comments on DTDs not conveying semantics.

But you agree that if we had XML schema-defined XHTML+RDFa, then it
would be no problem to GRDDL the document using a namespace-level
transformation, correct? In other words, an XML schema can convey
semantics. So why not a DTD? They play essentially the same role. We'd
love to be doing XML-schema only, but the w3c validator isn't quite
ready for that.

-Ben
Received on Monday, 25 June 2007 23:53:09 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 21:50:23 UTC