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Re: title element, meta, h1 and rdfa

From: Mark Birbeck <mark.birbeck@formsPlayer.com>
Date: Fri, 31 Aug 2007 12:46:31 +0100
Message-ID: <a707f8300708310446l1230ea91xbb1d6da3da968b6e@mail.gmail.com>
To: "Karl Dubost" <karl@w3.org>
Cc: RDFa <public-rdf-in-xhtml-tf@w3.org>

Hi Karl,

I don't recall this being discussed in the task force, so it would be
interesting to hear other views. However, it *was* discussed in the
XHTML 2 Working Group when we first started to work on RDFa, and we
concluded:

 * that you can't really have priorities for the triples, since that
makes parsing very complex. Any
   'priorities' or overlaid meanings need to come from an
interpretation of the derived triples, and
   not by trying to understand the triples in the parsing stage;

 * as with your comment, we also thought that <title> should express dc:title.

The h:title => dc:title part is a little controversial, and in
particular it does favour one taxonomy over others. As a consequence
it hasn't been introduced into the XHTML+RDFa 'dialect' that is being
worked on in the task-force. However, seeing your examples, I'm now
wondering whether having this 'shorthand' for dc:title is a good idea
at all!

What we could do instead is to say that, yes, <title> is a shorthand,
but that it generates a predicate in the XHTML namespace, rather than
Dublin Core's:

  <> xh:title "The Old Man And The Sea - Literature" .

(Note that if there is no mark-up in the element content, we don't
default to XML literals.)

With this triple it would be a simple matter to establish precedence
when presented with the following triples from your example:

  <> dc:title "The Old Man And The Sea, Ernest Hemingway" .
  <> dc:title "The Old Man And The Sea, Hemingway" .
  <> xh:title "The Old Man And The Sea - Literature" .

The key point is that the precedence is worked out at the level of the
generated triples, and not whilst in the process of parsing the
initial mark-up, which is bound to be better.

Note by the way that strictly speaking the <title> is the title of the
information resource sitting at the current URL, and therefore can't
be the title of a book. So in reality this problem of 'priority'
arises in situations like news stories, where the article title is in
the first <h1> as well as in <title>. The odd thing here though is
that you might actually want <h1> to take precedence.

The situation that would seem to be the most common would be something
like the following, from today's Times:

  <html>
    <head>
      <title>
        Empty seats at service show scars of Diana&rsquo;s life have
not all healed
      </title>
    </head>
    <body>
      <h1 class="heading">
        Empty seats at service show scars of Diana&rsquo;s life have
not all healed
      </h1>
      ...
    </body>
  </html>

Reading @class="heading" as @property="dc:title", we see that the two
titles are exactly the same.

However, The Sun, has the story like this:

  <html>
    <head>
      <title>
        The Sun Online - Royals: Diana tribute gets underway
      </title>
    </head>
    <body>
      <h1 class="black32">
        Diana tribute gets underway
      </h1>
      ...
    </body>
  </html>

It's quite a reasonable use of <title> since it will appear in search
engines and in the title bar of the browser--but which would we say is
the 'real' title here?

Regards,

Mark

On 31/08/2007, Karl Dubost <karl@w3.org> wrote:
>
> Hi,
>
> I would like to know if there's a rule for getting the meaning of
> this document.
>
> The XHTML document is located at
> http://example.org/foo/bar
>
> The markup is
>
> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML+RDFa 1.0//EN"
>   "http://www.w3.org/MarkUp/DTD/xhtml-rdfa-1.dtd">
> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
> <head>
>      <meta name="dc:title" content="The Old Man And The Sea, Ernest
> Hemingway" />
>      <title>The Old Man And The Sea - Literature</title>
> </head>
> <body>
> <h1>Book <span property="dc:title">The Old Man And The Sea,
> Hemingway</span></h1>
> </body>
> </html>
>
>
> Two solutions
> <> dc:title "The Old Man And The Sea, Ernest Hemingway"^^XMLLiteral .
> <> dc:title "The Old Man And The Sea, Hemingway"^^XMLLiteral .
>
> And another third one from the XHTML title element?
>         (if title is considered to be dc:title. More on that later.)
> <> dc:title "The Old Man And The Sea - Literature"^^XMLLiteral .
>
>
> * Are there rules of precedence in RDFa?
> * Is there a need to explain the semantics conformance of HTML-like
> languages?
>
>
>
> --
> Karl Dubost - http://www.w3.org/People/karl/
> W3C Conformance Manager, QA Activity Lead
>    QA Weblog - http://www.w3.org/QA/
>       *** Be Strict To Be Cool ***
>
>
>
>
>


-- 
  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 Friday, 31 August 2007 11:46:46 GMT

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