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Re: Using the CLASS attribute - Request for Feedback

From: Elias Torres <elias@torrez.us>
Date: Thu, 12 Oct 2006 18:21:56 -0400
Message-ID: <452EC004.30806@torrez.us>
To: Bjoern Hoehrmann <derhoermi@gmx.net>
CC: public-rdf-in-xhtml-tf@w3.org

Bjoern Hoehrmann wrote:
> * Elias Torres wrote:
>> Maybe that's the very reason we have GRDDL for which is to have specific
>> logic to extract semantics from existing web pages. However, if someone
>> were to use the same combination (e.g. just "fn") in a @class in a
>> webpage GRDDL will extract a vcard and that was very much unexpected.
> These are all opt-in processes, if you want your markup interpreted in
> some specific way, you identify what your markup conforms to, or how to
> map it to something else, using a 'transform' link relationship, or a
> proper profile="..." list, or whatever the applicable specification
> recommends.

That's correct. The author has to specify intention through profile/link
which is really good, as good as GRDDL is because everyone is stating
their intentions very clearly. However neither of those are widely
deployed or in place for use (I confess I have not been following the
TODO from DanC to institute profile URLs for most microformats) and the
current state of the world for microformats and their parsers is to go
directly at the class names.

>> Microformats uses @class for both types and predicates and only a
>> specific extraction mechanism is capable of understanding the
>> difference. I like that (GRDDL) and actually drives me to wrestle with
>> the problem (I think) that whether we use @class or not, we still use
>> rel/rev/href/meta/property and there's always going to be the question
>> whether extracted triples from the page were expected or not.
> How is this true for, say, eRDF?

In a previous email to Ben you came with excellent cases we need to
consider in the spec. That's exactly what we were hoping by asking the

  class='http://example.org/a http://example.org/b'
  class='a#b#c #d#e#f#'

In the same way eRDF uses @class to specify triples but uses '-' instead
of ':'.

For example:

<span class="foaf-name"><span class="foaf-firstName">Anna</span>
<span class="foaf-surname">Wilder</span></span>.
<img src="pic.jpg" class="foaf-depiction" alt="A picture of me"/>

However the difference is that eRDF does make use of the profile
attribute to indicate intent. Would you think that adding a profile to a
page to indicate RDFa intent would solve the expectation problem? We
could also define ways to exclude invalid class names as the ones you
point out from generating triples. Your feedback is appreciated and most
definitely welcome.

Received on Thursday, 12 October 2006 22:22:15 UTC

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