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Re: longdesc URLs and RDFa

From: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>
Date: Wed, 18 Aug 2010 12:33:09 +0200
To: Ivan Herman <ivan@w3.org>
Cc: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>, Shane P McCarron <shane@aptest.com>, martin@weborganics.co.uk, W3C RDFa WG <public-rdfa-wg@w3.org>
Message-ID: <20100818123309071160.bb82204e@xn--mlform-iua.no>
Ivan Herman, Wed, 18 Aug 2010 06:48:43 +0200:

> You said that the floodgate was opened when RDFa accepted @href and 
> @src. While this may very well be true, what you describe in your 
> examples go further. To stick to @longdesc, you seem to ask not only 
> to interpret @longdesc somehow, but also to assign a specific 
> property to it from the foaf namespace (and the same for @alt).

I think you are shooting outside the target.  I have not seen the FOAF 
use cases that made you take @src into the RDFa syntax - you seemed to 
say that that was what happened. But I don't believe @src is especially 
connected to FOAF, just because FOAF use cases made you take it into 
the syntax. I juxtaposed @data with @src - in a FOAF example -  in one 
of the use cases. It is unfair to believe that I want a special link to 
FOAF for that reason.

And it was not my intention to link @longdesc to a particular 
vocabulary. I simply tried to, on your request,  provide use cases "to 
interpret @longdesc somehow". It should be simple to see from the use 
case I provided that I suggest to look at @longdesc as conceptually 
identical to @resource/@href. 

To be very clear, it was my intention to say that it instead of doing 
the following - which is necessary today:

    <img xmlns:foaf="http://xmlns.com/foaf/0.1/"
                src="diagram.png" 
                rel="foaf:depicts"
           resource="diagram-data-as-a-table.html"
           longdesc="diagram-data-as-a-table.html"
           property="foaf:topic"
                alt="Development last six months."
            content="Development last six months."  
    />

it should be enough to do this:

    <img xmlns:foaf="http://xmlns.com/foaf/0.1/"
                src="diagram.png" 
                rel="foaf:depicts"
           longdesc="diagram-data-as-a-table.html"
           property="foaf:topic"
                alt="Development last six months."
    />


> This 
> is a significant step further than the usage of @href/@src which 
> simply set the object or subject of triples.

In the use case above, the @longdesc simply sets the object.

> Other than that, RDFa is 
> almost completely agnostic as for what vocabularies are used in the 
> triples, except for some of the 'inherited' historical @rel values 
> that (X)HTML carries (like 'next' or 'stylesheet').
> 
> In effect: the proper and complete logical approach along the lines 
> of what you say is:
> 
> 1. make a thorough analysis of the whole of XHTML to find those 
> attributes and possibly elements that have a 'semantic' 
> interpretation in an RDF sense

Even if I "went to far", this step does not sound very bad. However, by 
the logic I followed, it is still _not_ necessary to go this far. 
Instead, it only requires that one goes through the language (yes!) and 
identify _the "floodgate"_ that was opened through support for @src, 
@href and @content. I don't see @title in that flood. I have not seen 
any arguments that support that @title is in that flood.

> 2. define the exact processing steps, ie, the extensions for the 
> general, RDFa Core processing steps for each of these

I don't think I have suggested anything more specific for @longdesc and 
@cite than the language already says about @href and @resource. I 
think, what is needed, is to specify which attribute takes priority, if 
more than one is present.

> To be very honest with you, and I must emphasize that this is my 
> private opinion, I believe this goes beyond what this Working Group 
> can, and indeed should do...

Till now, I have not become convinced that you look at the same idea 
that I do. I hope what I said above, will make that clearer.
-- 
leif halvard silli
Received on Wednesday, 18 August 2010 10:33:42 GMT

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