W3C home > Mailing lists > Public > public-xhtml2@w3.org > February 2009

Re: [Fwd: Using XMLNS in link/@rel]

From: Steven Pemberton <steven.pemberton@cwi.nl>
Date: Fri, 27 Feb 2009 11:06:35 +0100
To: "Mark Nottingham" <mnot@mnot.net>, www-tag@w3.org
Cc: "Dan Brickley" <danbri@danbri.org>, "Ben Adida" <ben@adida.net>, RDFa <public-rdf-in-xhtml-tf@w3.org>, "XHTML WG" <public-xhtml2@w3.org>
Message-ID: <op.upz809cnsmjzpq@acer3010.wlan.cwi.nl>
On Fri, 27 Feb 2009 10:31:57 +0100, "Mark Nottingham" <mnot@mnot.net> said:
> Creative Commons just released a new spec:
>    http://wiki.creativecommons.org/Ccplus
> that has markup in this form:
>    <a xmlns:cc="http://creativecommons.org/ns#"
> rel="cc:morePermissions" href="#agreement">below</a>
> (in HTML4, one assumes, since they don't specify XHTML, and this is
> what the vast majority of users will presume).

In the link you refer to they don't specify either, but I imagine they  
mean XHTML, and I'm sure Ben Adida of CC can speak up here.

> However, it appears that they adopted this practice from RDFa;
>    http://www.w3.org/TR/rdfa-syntax/#relValues
> which, in turn, *does* rely upon XHTML. However, XHTML does *not*
> specify the @rel value as a QName (or CURIE, as RDFa assumes);
> http://www.w3.org/TR/2008/REC-xhtml-modularization-20081008/abstraction.html#dt_LinkTypes
>"Note that in a future version of this specification, the Working
> Group expects to evolve this type from a simple name to a Qualified
> Name (QName)."
> So, that's an expectation, not a current specification.

In fact it is a current specification. RDFa specifies a version of XHTML  
that defines the meaning of CURIEs in rel and rev values. Note that this  
is also not invalid HTML4 (which also allows such values in a rel - they  
are CDATA - but doesn't specify what they mean).

> Of course, this conflicts with the Link draft;
>   http://tools.ietf.org/id/draft-nottingham-http-link-header-04.txt
> which we've worked pretty hard to come to consensus on across a broad
> selection of communities (Atom, POWDER, OAuth, HTTP, and
> optimistically, HTML5).
> A few observations and questions;
> 1) I'm more than happy to specify in the Link that in XHTML, a link
> rel value is indeed a QName, if XHTML chooses to take that position
> (although I believe a URI is a better fit than a QName here, as in
> most other places). Can we get a current reading from the XHTML world
> on this?

A CURIE is a URI not a QName, so you're OK. CCing the XHTML2 WG and/or  
RDFa group would have helped in this case if you wanted a response from  
them :-)

> 2) However, it seems like RDFa is jumping the gun by assuming @rel is
> a CURIE right now.

See above. It is already a Rec.

[All the rest snipped since it was based on the assumption that XHTML+RDFa  
isn't a Rec].

> P.S., I realise that this involves at least three additional
> communities, but the TAG seems like the logical place for the initial
> discussion and eventual coordination of this issue.

CCing all groups involved always helps in getting everyone's attention.

Best wishes,

Steven Pemberton
Received on Friday, 27 February 2009 10:06:50 UTC

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