As noted on the LOD and POWDER mailing lists in recent days, the revived
303/200 with content-location header debate brought to my attention the
mismatch in the documentation of wdrs:describedby.
Two headlines
=============
1. On behalf of the former POWDER WG, I apologise for the confusion and
for the fact that we hadn't realised the mistake earlier.
2. It has now been fixed as far as it can be for now, with the
expectation of a complete fix in the new year.
Brief detail
============
The @rel type of 'describedby' is introduced at [1] and formally defined
at [2] thus:
"The relationship A 'describedby' B asserts that resource B provides a
description of resource A. There are no constraints on the format or
representation of either A or B, neither are there any further
constraints on either resource."
The namespace document for wdrs [3] has now been edited to make it clear
that wdrs:describedby is semantically identical to this. The previous,
erroneous, range restriction has been removed.
Much as I wish I could, I can't just edit the actual POWDER
Recommendation - that requires the following of a change process.
However, I have published an erratum [4] that makes it clear what edits
are expected to be made once the process has been followed (as well as a
link to details of the process itself, currently in draft form). The
erratum gives full details of the issue and points to the mailing list
through which comments can be made.
It's worth noting in this context that the @rel value describedby is
included Mark Nottingham's Web linking document, that has now, at last,
become an RFC [5].
So, with confidence, we can say that all of the following are legitimate
and semantically identical:
(X)HTML, ATOM
<link rel="describedby" href="/doc" type="foo/bar" />
HTTP
Link: </doc>; rel="describedby" type="foo/bar";
RDF
@prefix wdrs: <http://www.w3.org/2007/05/powder-s#> .
<> wdrs:describedby </doc> .
Phil.
[1] http://www.w3.org/TR/powder-dr/#assoc-linking
[2] http://www.w3.org/TR/powder-dr/#appD
[3] http://www.w3.org/2007/05/powder-s.html#describedby
[4] http://www.w3.org/2007/powder/powder-errata#describedby
[5] http://tools.ietf.org/html/rfc5988
--
Phil Archer
Former POWDER WG chair
http://philarcher.org/
@philarcher1
N.B. For POWDER-related issues neither my Talis nor my W3C Team
affiliation is appropriate. Instead, I am allied to Institute of
Informatics & Telecommunications (IIT), NCSR "Demokritos" for this.
