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Re: longdesc URLs and RDFa

From: Ivan Herman <ivan@w3.org>
Date: Wed, 18 Aug 2010 12:44:30 +0200
Cc: Shane P McCarron <shane@aptest.com>, martin@weborganics.co.uk, W3C RDFa WG <public-rdfa-wg@w3.org>
Message-Id: <30808206-B8D3-4296-BDF1-5B1292163B08@w3.org>
To: Leif Halvard Silli <xn--mlform-iua@xn--mlform-iua.no>

thanks. I think I indeed misunderstood you. If I concentrate on the image related attributes, what you seem to say is that:

- the value of @longdesc should be treated as if it was a @resource
- the value of @alt should be treated as if it was @content

and that is all. Correct?

Sorry for the misunderstanding


On Aug 18, 2010, at 12:33 , Leif Halvard Silli wrote:

> 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

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 Wednesday, 18 August 2010 10:43:00 UTC

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