W3C home > Mailing lists > Public > public-rdf-in-xhtml-tf@w3.org > October 2006

Re: Using the CLASS attribute - Request for Feedback

From: Bjoern Hoehrmann <derhoermi@gmx.net>
Date: Thu, 12 Oct 2006 23:48:26 +0200
To: Ben Adida <ben@mit.edu>
Cc: public-rdf-in-xhtml-tf@w3.org
Message-ID: <vkcti2dvab0dc8tmend9vn44b7l25o54nh@hive.bjoern.hoehrmann.de>

* Ben Adida wrote:
>All active members of the task force are currently in agreement that the
>CLASS attribute in HTML should be viewed as an rdf:type declaration on
>that element. Of course, we want to do this such that no unexpected
>triples are produced by unsuspecting HTML authors.

What is the requirement this proposal attempts to address?

>Under our proposal, here's what would happen:
>EXAMPLE 1: non-namespaced CLASS

This is a pleonasm.

><div class="menu">
>yields the triple:
>_:div0 rdf:type :menu
>where ":menu" is locally scoped (in some way we're still working on.)

If you are not actually sure what you are proposing, why are you
proposing it then?

>This effectively expresses exactly what the HTML says: this DIV is of
>type "menu", where the concept of "menu" is defined locally and likely
>has nothing to do with any other web page's concept of "menu."

No, "the HTML" does not "say" that. The class attributes associates
elements with a set of class names, the element is said to belong to
the set of class names. You are trying to turn this into an instance
of relationship. A "break" belongs to a "car", it is not however an
instance of a car. Likewise, the HTML 4.01 specification does not re-
quite a specific class name to imply the same thing regardless of
where it occurs. Finally, I do not understand what it could mean for
something to be an instance of a "small", "invisble", "whiteout",
"hide", or "conform", all of which would be rdf:types of the W3C home
page under your proposal.

Of course, none of this a problem for your proposal as deriving the
triples as you propose is entirely meaningless. Which, again, leaves
me wonder what requirement you are trying to address. What is it that
requires an application to derive triples like

  _:x0 rdf:type :small

from <http://www.w3.org/>?

>EXAMPLE 2: namespaced CLASS

There is no such thing in any current or proposed version of HTML or

><div class="foaf:plan">
>yields the triple:
>_:div0 rdf:type foaf:plan
>exactly as expected.

Again, you completely fail to actually propose how this would look
like, I cannot tell from your proposal what, for example, any of the
following map to,

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

even though these are all perfectly permissable class names in HTML
4.01, XHTML 1.0, etc.

>Please send your feedback in response to this message. There's good
>precedent for using the CLASS attribute in this way (eRDF,
>microformats), and we feel that the result should never yield anything
>unexpected to the HTML author.

No, neither of them do anything similar.
Björn Höhrmann · mailto:bjoern@hoehrmann.de · http://bjoern.hoehrmann.de
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Received on Thursday, 12 October 2006 21:48:35 UTC

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