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Re: XHTML2 and metainformation

From: Andy Powell <a.powell@ukoln.ac.uk>
Date: Fri, 16 May 2003 23:54:57 +0100 (BST)
To: www-html@w3.org
Message-ID: <Pine.GSO.4.53.0305162330400.4812@lamin.ukoln.ac.uk>

Ernest Cline wrote...

> Let me first quote from an earlier post of mine on this subject, since
> its been almost a month since it was made:
> # If RFC 2731 is to be adapted so as to be part of XHTML2, then it
> # should be referenced normativly in the recommendation.  Currently
> # it has only a mention as part of an unreferenced example in the
> # Metainformation Module.
> #
> # Clearly a method of associating metainformation with a
> # schema/profile SHOULD be standardized in XHTML2 and incorporated
> # as part of the Metainformation Module.  The chosen method is of
> # secondary importance.
> # There are three methods I see of doing this in XHTML. One would be a
> # minimal rewriting of RFC 2731 so as to adapt it to syntax of XHTML2.
> #
> # This would look something like:
> #     <link rel="schema.DC" href="http://purl.org/dc/elements/1.1/" />
> #     <meta name="DC.Date">2000-01-01</meta>
> # Another would be similar to RFC 2731, but instead of link would use a
> # new element defined in the Metainformation Module and look something
> # like this:
> #     <schema name="DC" profile="http://purl.org/dc/elements/1.1/" />
> #     <meta name="DC.Date">2000-01-01</meta>
> # The third would be like my initial proposal:
> #     <ml profile="http://purl.org/dc/elements/1.1/">
> #       <mi name="Date">2000-01-01</mi>
> #     </ml>
> # Of these three formats, I really don't like the first as I think that
> # associating metainformation with its schema is a task that should not
> # be left to <link> but should have its own element. I have a slight
> # preference for the third format, but would have no complaints if
> # something like the second format were incorporated into XHTML2.
> # Leaving the association of metainformation with its schema to a
> # non-W3C extension is in my opinion totally unacceptable. Even
> # sanctioning the first format above and making it normative would be
> # preferable.
> At the time of that discussion, no mention was made of the desirability
> of using a schema to specify new link types for use with <link> or <a>.
> If such an ability is desirable then I agree that the third format
> I gave is insufficient.  Of the two remaining formats, I'd prefer
> something like the second where a specific element such as <schema> for
> making that association is used instead of doling that job off to
> <link>, especially if one of the jobs of the this method is to assign
> possible linktypes for <link> to use. Elements that could modify their
> own interpretation make me suspiscious.

It'd be good to try and find a way to involve the DCMI (in particular the
DCMI Architecture WG at http://dublincore.org/groups/architecture/ ) in
your discussions about embedding DC metadata in XHTML 2.  In particular,
you might be interested in the DCMI Working Draft at


I'd certainly be interested in your comments on this document.  The
current intention is to move this document, or a version of it, thru the
DCMI Recommendation process.

In any case, it is worth noting that

- all DC element names start with a lower-case letter (i.e. date rather
  than Date)

- it seems sensible to move to a syntax that more closely mirrors the
  encoding of DC in XML and RDF/XML (i.e. dc:date rather than DC.Date)

- it is not clear to me that it is sensible to re-use DCMI namespace URIs
  (e.g. http://purl.org/dc/elements/1.1/) to identify 'profiles' - a
  profile (at least as far as I understand it) may want to use metadata
  properties from multiple namespaces.  Keeping these things separate is
  akin to the  separation of XML namespace URIs and XML schema URIs.

- DC applications currently use the scheme attribute of the HTML
  meta element (see the document above).  It'd be good not to lose this
  attribute (or an equivalent) in XHTML 2.

Distributed Systems, UKOLN, University of Bath, Bath, BA2 7AY, UK
http://www.ukoln.ac.uk/ukoln/staff/a.powell       +44 1225 383933
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Received on Saturday, 17 May 2003 15:50:07 GMT

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