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Re: [RDFa] ISSUE-28: following your nose to the RDFa specification

From: Ben Adida <ben@adida.net>
Date: Thu, 21 Jun 2007 12:12:45 -0700
Message-ID: <467ACDAD.7060101@adida.net>
To: Dan Connolly <connolly@w3.org>
CC: mark.birbeck@x-port.net, RDFa <public-rdf-in-xhtml-tf@w3.org>, SWD WG <public-swd-wg@w3.org>

Dan Connolly wrote:
> This issue is about the case where you do find an RDFa
> attribute (about/resource/etc); how do
> you know that the author meant it in the RDFa sense?

[...]

> No, at worse you get some triples out that the author didn't intend
> because s/he didn't mean the markup to have RDFa meaning.

You have to be realistic: separate the spec from what people do in
practice. Take microformats for example. Their spec says that users must
have a PROFILE attribute. Deployments show that this is almost never the
case, meaning that microformat parsers out there are assuming tons of
stuff about what authors say when they didn't "intend to."

I don't see you arguing that these parsers should stop what they're
doing, rather I see you arguing that people should add profiles.
Similarly, we're not going to tell people to stop looking for RDFa, but
we are going to tell RDFa publishers to put the right DTD declaration
and we are going to tell the HTML WG to make their spec extensible
enough so that publishers can do the right thing and declare their usage
of RDFa.

(It is interesting to note that if the HTML WG chooses to not make HTML
extensible, then that will clearly encourage ad-hoc HTML extensions
where you *can't* follow your nose. You can't stop the desire for
semantic markup, you can only attempt to guide it.)

If you're arguing that we should tell people to strictly *not* look for
RDFa unless there is a DTD or profile, then I strongly disagree.

In an ideal world, folks will move to a DTD/schema where the RDFa syntax
means something explicitly every time. If they don't, assuming RDFa
markup is certainly no worse than assuming 20 different microformat
profiles. In fact, I consider it a much lesser offense, since we've
already modified the RDFa syntax a few times so that it is extremely
unlikely for someone to write RDFa syntax without actually intending to.
It is a lot easier to accidentally use a "reserved" microformat class name.

As to the copy-and paste issue... there's a point that you seem to miss
when you conflate DTD/mime-type and GRDDL PROFILE. With GRDDL and
microformats, the PROFILE is *necessary* to figure out what the author
means: you can copy and paste ONLY if you modify the HEAD of the
document with each copy-paste operation to keep the *meaning* around. If
all pages are RDFa enabled with the right DTD, then copy-and-paste works
just fine: the HEAD of the document does not need to contain any
vocabulary-specific information, so it does not need to change with
every copy-and-paste operation. In other words, the isse is not whether
you have to modify the HEAD of the document, it's whether that
modification is vocabulary-specific. In the case of RDFa, it's not. That
makes the inevitable promiscuous parsing situation a bit more reasonable.

-Ben
Received on Thursday, 21 June 2007 19:13:20 UTC

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