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Re: RDFa Core 1.1 feedback

From: Toby Inkster <tai@g5n.co.uk>
Date: Sun, 2 May 2010 12:52:21 +0100
To: Gregg Kellogg <gregg@kellogg-assoc.com>
Cc: "public-rdfa-wg@w3.org" <public-rdfa-wg@w3.org>
Message-ID: <20100502125221.32c917d2@miranda.g5n.co.uk>
On Sat, 1 May 2010 22:59:27 -0400
Gregg Kellogg <gregg@kellogg-assoc.com> wrote:

>  *   Section 9 Note 3: Indicates that if a subject has more than one
> triple with a predicate of rdfa:uri or rdfa:term, all triples
> associated with the subject should be ignored (how I read it). What
> if there are multiple values for rdfa:prefix? Does this imply
> multiple prefix mappings, is is this also invalid?

Indeed, this section needs tightening up.

We need to consider what mappings are established in these three cases:

	## Multiple URIs
	[] rdfa:term "Person" ; rdfa:uri <a> , <b> .

	## Multiple terms
	[] rdfa:term "Person" , "Dude" ; rdfa:uri <a> .

	## Multiple terms and URIs
	[] rdfa:term "Person" , "Dude" ; rdfa:uri <a> , <b> .

And the corresponding rdfa:prefix cases. Also:

	## Both these in the same profile
	[] rdfa:term "Person" ; rdfa:uri <a> .
	[] rdfa:term "Person" ; rdfa:uri <b> .

Relying on the order that the mappings are specified might work for
profiles written in RDFa, but what about profiles written in other
profile serialisations? In many cases, RDFa parsers will hook into
third-party parsers for those, and it's unlikely they'll be able to
rely on triples being returned in any particular order.

A good method of tightening up the definition of profiles might be for
the spec to provide SPARQL SELECT queries that should be applied to
profiles to yield the lists of mappings. (Implementations would not be
required to implement SPARQL, but could use any technique to extract
the lists of mappings which yielded the same results.)

I don't actually see any harm in allowing terms to be expanded to
multiple URIs. So, for example the term "title" could be mapped to
both dcterms:title and rdfs:label. This would allow for profiles to be
created that, say, simultaneously provided data in FOAF plus Google's
vocab.

-- 
Toby A Inkster
<mailto:mail@tobyinkster.co.uk>
<http://tobyinkster.co.uk>
Received on Sunday, 2 May 2010 11:54:02 UTC

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