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Re: RDFa Vocabularies

From: Ivan Herman <ivan@w3.org>
Date: Tue, 12 Jan 2010 10:57:16 +0100
Message-ID: <4B4C477C.5030806@w3.org>
To: Manu Sporny <msporny@digitalbazaar.com>
CC: RDFa mailing list <public-rdf-in-xhtml-tf@w3.org>
Manu,

thanks for writing this down.

All in all, I am a little bit wary of this proposal. It does put an
extra load on implementation that is non negligible.... I also have
questions:

- implementations will be incompatible as for what the format of the
document at the value of @vocab is. The text says:

[[[
The attribute's value should contain one or more space-separated URLs.
Each URL, when dereferenced, should provide a document marked up with
the RDFa Vocabulary
]]]

but it does not specify the serialization formats. There can be many:
RDF/XML, RDFa, Turtle, XHTML+GRDDL... This may lead to deployment issues
for users. It is also the source of complication for implementations:
would they have to include an RDF/XML parser into their RDFa
implementation (after all, besides RDFa, RDF/XML is, up to now, the only
standard serialization format for RDF; well, one can argue that
XHTML+GRDDL is another one...)

I wonder whether we should not restrict ourselves to RDFa as an accepted
format. Implementations still have to, sort of, recursively call
themselves to interpret vocabulary files, but at least no further parser
is necessary.

- there is a danger for cycles. Say

Doc A with URI <http://www.example/org/A>:

<bla vocab="http://www.example/org/B">....

Doc B with URI <http://www.example/org/B>:

<blabla vocab="http://www.example/org/A">....

then, well, we may have a problem. We have to have a standard strategy
of action for this case.

Ivan



On 2010-1-12 05:01 , Manu Sporny wrote:
> I had an action to generate spec text for pulling in external vocabulary
> documents. Here's the first cut:
> 
> This document outlines an extension to the the syntax and processing
> rules that would allow the list of reserved words recognized by RDFa to
> be extended. The goal of this mechanism is to make authoring RDFa easier
> for web developers and designers.
> 
> http://rdfa.digitalbazaar.com/specs/rdfa-vocab-20100111.html
> 
> -- manu
> 
> [1] http://www.w3.org/2010/01/07-rdfa-minutes.html#action03
> 

-- 

Ivan Herman, W3C Semantic Web Activity Lead
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Received on Tuesday, 12 January 2010 09:56:39 UTC

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