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Re: Another way other than @profile, @vocab or @map

From: Martin McEvoy <martin@weborganics.co.uk>
Date: Fri, 19 Mar 2010 15:36:25 +0000
Message-ID: <4BA399F9.2020601@weborganics.co.uk>
To: Shane McCarron <shane@aptest.com>
CC: Toby Inkster <tai@g5n.co.uk>, Ivan Herman <ivan@w3.org>, RDFa WG <public-rdfa-wg@w3.org>
On 19/03/2010 15:16, Shane McCarron wrote:
> I have always felt that we need a way to permit the definition of a 
> new default prefix.  In fact, if you look at 
> http://rdfa.info/wiki/RDFa_Vocabularies you can see the wiki page Manu 
> and I started developing about it ages ago.  Toby, you even 
> contributed to it!

Yes I remember that discussion.. It kind of lost momentum as I recall ;)

> Actually, looking back, what that proposal did was conflate a couple 
> of things... but I still think it is mostly clean. I updated it to use 
> the attribute name @vocab, because I agree that it is meaningful.  
> Note that in this proposal @vocab can be used to declare a default 
> prefix, declare other prefix mappings, AND implies a follow-your-nose 
> vocabulary extension mechanism.  Also note that in this proposal the 
> target document is an RDFa document that uses the link element with a 
> special @property value to define additional prefix mappings if it 
> wants to.
> I am not really trying to muddy the waters here, but I suppose I am by 
> introducing yet another way of thinking about this.  The nice thing 
> about this mechanism is that we could just remove the bits about 
> retrieving a remote document altogether.  It is a way to extend the 
> collection of prefixes and keywords, but it is not really required in 
> my opinion.  Not for the use cases I can think of.

No you are not muddying the waters at all  I belive that Its the same 
discussion almost as the one we are having here.. this example..


is particularly relevant to this discussion, it should have been solved 
back then in version 1.0 of RDFa as being able to declare a default 
name-space is a basic function of RDF.

anyway +1 for using the url @vocab to declare the default CURIE prefix, 
I would like to add that @vocab should only be used once in a RDFa 
document to avoid invalid RDF in the output document (switching default 

Best Wishes.


> Martin McEvoy wrote:
>> Hello Toby,
>> On 19/03/2010 13:47, Toby Inkster wrote:
>>> On Fri, 2010-03-19 at 12:21 +0000, Martin McEvoy wrote:
>>>> @profile in this way is behaving just the same as html4 profiles..
>>>> "As a globally unique name. User agents may be able to recognize the
>>>> name (without actually retrieving the profile) and perform some
>>>> activity based on known conventions for that profile"
>>>> http://www.w3.org/TR/html401/struct/global.html#profiles
>>>> In the case of RDFa the "known conventions" would be setting the
>>>> default namespace for the document.
>>> Not quite the same. "name" in the quote above can be translated as
>>> "URI". So when it says:
>>>     "user agents may be able to recognize the name"
>>> it means that user agents should only be doing this for URIs that they
>>> recognise. Unless I'm misunderstanding your suggestion, RDFa processors
>>> would be applying the profile as a default prefix whether or not they
>>> recognised the URI.
>> Yes they would be applying the profile as a default CURIE prefix 
>> whether or not they recognise it, ... hmm sounds a little unsafe..  
>> but isn't that what we are suggesting with the rdfa profile proposal, 
>> perhaps I am misunderstanding something ;)
>>> I don't have anything against this general technique - but I don't 
>>> think
>>> it's consistent with the HTML4/XHTML1.x definition of @profile, so a
>>> different attribute would need to be used.
>> I agree (now)  best to avoid @profile and use something new, like 
>> your original proposal, Im glad we discussed its uses first though.
>> http://lists.w3.org/Archives/Public/public-rdf-in-xhtml-tf/2010Jan/0019.html 
>>> A lot of the debate here has been on the syntax and model for profile
>>> documents. Personally I don't think we've had enough debate on whether
>>> profile documents are needed at all
>> I agree ...
>>>   - Martin's suggestion here is not to
>>> define a profile (in the sense that we've been talking about them) at
>>> all, but to just set the default CURIE prefix.
>> Which in my mind is the simplest problem to solve ....
>>> What exactly are the use
>>> cases that show this to be insufficient? Personally, I don't think I've
>>> seen any yet.
>> :)
>> I believe If this group can come to a decision on "how to declare the 
>> default CURIE prefix" a lot of the other problems such as 
>> "prefix-less tokens" and google wanting  to "bundle a bunch of 
>> existing vocabs together" may have agreeable outcome to a certain 
>> extent.
>> @vocab as new attribute name is looking pretty desirable now ;)
>> Best wishes.

Martin McEvoy
Received on Friday, 19 March 2010 15:36:51 UTC

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