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Re: [POWDER] About describedby

From: Phil Archer <phil@philarcher.org>
Date: Tue, 02 Dec 2008 09:55:28 +0000
Message-ID: <49350610.1030309@philarcher.org>
To: Andrea Perego <andrea.perego@uninsubria.it>, Public POWDER <public-powderwg@w3.org>

Thanks for this Andrea - it gives me a chance to set things out clearly 
(which I should have done for yesterday's telecon).

Andrea Perego wrote:
> Hi, Phil.
> 
> Could you please remind me why we should drop the range specification
> for describedby? Is it about using it in ATOM?

No, it's not related to it being used for ATOM as such. In my original 
e-mail to IANA, included in the mail at [1], it says:

"The relationship A 'describedby' B does not imply that B is a POWDER 
file (the MIME type does that), simply that B provides a description of 
A. The representation returned from A and B is not constrained by the 
relationship."

Following feedback from Julian Reschke (and a chat on the phone with 
him) I've proposed some amendments to the DR doc reported to the group 
at [2] with the relevant changes visible temporarily at [3]. It looks 
like a big re-write of that section on linkage but it isn't. All I've 
done is to re-order the sections a little and shown how link @rel 
elements can be used in ATOM. However, when the wdrs:describedby 
property is introduced [4] I've suggested that we say:

The meaning of wdrs:describedby is identical to the describedby 
relationship type defined above so that:

http://www.w3.org/2007/05/powder-s#describedby

and

http://www.iana.org/assignments/relation/describedby

For this to be true, bearing in mind the requested registration of 
describedby, we need to drop the range constraint.

The upside of doing this is that we keep the @rel type and the RDF 
vocabulary term consistent with each other. In the RDFa example (now 
numbered 4-3) the type attribute is still there to hint that the target 
of the link is a POWDER document. The downside is that this is not true 
for the second RDFa example, now numbered 4-4.

Given all that - do you agree that we can drop the range constraint? If 
not, then I can only suggest that we should define a different, 
POWDER-specific, vocabulary term for use in RDFa - but then I fear that 
might be confusing since RDFa allows @rel types [5] and it's going to 
get messy.

Phil.


[1] http://lists.w3.org/Archives/Public/public-powderwg/2008Nov/0016.html	
[2] http://lists.w3.org/Archives/Public/public-powderwg/2008Nov/0021.html
[3] http://philarcher.org/powder/20081124.html#assoc
[4] http://philarcher.org/powder/20081124.html#semlink
[5] http://www.w3.org/TR/rdfa-syntax/#rdfa-attributes

-- 

Phil Archer
w. http://philarcher.org/
Received on Tuesday, 2 December 2008 09:56:14 GMT

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