W3C home > Mailing lists > Public > public-rdfa-wg@w3.org > May 2010

Re: On ISSUE-6 (invalid values in @datatypes cause plain literals to be generated)

From: Ivan Herman <ivan@w3.org>
Date: Mon, 17 May 2010 13:31:46 +0200
Cc: W3C RDFa WG <public-rdfa-wg@w3.org>
Message-Id: <D9093919-6429-49CA-AABB-6498B105B79E@w3.org>
To: Toby Inkster <tai@g5n.co.uk>

On May 17, 2010, at 12:21 , Toby Inkster wrote:

> On Mon, 17 May 2010 12:04:40 +0200
> Ivan Herman <ivan@w3.org> wrote:
>> - @datatype="***goofy***" is not an NCNAME ie, it is not a term; it
>> does not lead to a proper CURIE either because (prefix must be an
>> NCNAME); ie, it has to be processed as a URI, yielding the URI:
>> http://baseuri/***goofy***
> I was under the impression that the TERMorCURIEorURI attributes
> required full URIs, not just relative URI references, though this
> doesn't seem to be mentioned in the current core draft.

Well this was up and down during discussions leading up to RDFa1.1. But, at the moment, the management of TERMorCURIEorURI says (in 7.4)

   If the value is an NCName, then it is evaluated as a term according to General 
    Use of Terms in Attributes. Note that this step may mean that the value is to be ignored.
   Otherwise, the value is evaluated as a CURIE. If it is a valid CURIE, the resulting 
    URI is used; otherwise, the value will be processed as a URI.

and processing URI simply allows relative URI-s to be used. I agree an example using relative URI-s would be good but, I believe, spec-wise this is fairly clear.

> There seem to be very few use cases where relative references in
> @property, @rel, @rev, @datatype or @typeof would come in handy.

The fact of being able to use relative URI-s is some sort of a by-product of our great unification of terms, curies, and uri-s... So, in mind mind, the question does not arise in these terms but rather: what is the specific problem that forces us to artificially disallow relative URI-s? 

Note that the frequent usage for attribute values is something like


which will NOT be a relative URI, but will be interpreted (if possible) as a term. In practice, the situation for relative URI-s arises either in the slightly pathological example raised by Dan or when one fairly explicitly uses something like




and I do not see any problem having those... 


> Can we clarify this either way in the next draft?
> -- 
> Toby A Inkster
> <mailto:mail@tobyinkster.co.uk>
> <http://tobyinkster.co.uk>

Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
PGP Key: http://www.ivan-herman.net/pgpkey.html
FOAF: http://www.ivan-herman.net/foaf.rdf

Received on Monday, 17 May 2010 11:31:18 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 21:19:47 UTC