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Re: RDFa in HTML issues wiki page created

From: Julian Reschke <julian.reschke@gmx.de>
Date: Tue, 26 May 2009 13:44:05 +0200
Message-ID: <4A1BD605.70002@gmx.de>
To: Mark Birbeck <mark.birbeck@webbackplane.com>
CC: Sam Ruby <rubys@intertwingly.net>, Manu Sporny <msporny@digitalbazaar.com>, Philip Taylor <pjt47@cam.ac.uk>, RDFa mailing list <public-rdf-in-xhtml-tf@w3.org>, HTML WG <public-html@w3.org>
Mark Birbeck wrote:
> That isn't how it works at all.
> 
> Unlike other proposals of this ilk, which decide that there should be
> some kind of centralised registry, the RDFa solution was simply to say
> that any host language is free to define its own reserved words.

Understood, but not convinced.

So, as the lists of reserved terms are different for HTML4, XHTML+RDF, 
and HTML5, is RDFa extraction supposed to return different results? Is 
it, for that matter, supposed to check media type and doc type of the 
containing element before generating triples for non-CURIE values?

> Also, although the RDFa spec doesn't currently use the CURIE spec,
> they are in sync, and you'll see that the latter also specifically
> allows for predefined tokens to be processed first, before doing
> normal CURIE-processing.

...which makes it impossible to process IRIs as-is (without 
workarounds), as they use the colon character.

> The upshot of this approach in both RDFa and CURIEs, is that a
> language that 'hosts' RDFa (such as SVG-Tiny, XHTML 1.x, XHTML 2, HTML
> 4, HTML5 so on) or CURIES (such as @role), can define its own list of
> 'tokens' that are specific to its own language. However, tokens that
> include a prefix will be universal and will give the same URI in any
> host language.
> 
> This provides a good compromise between extensibility and
> domain-specific ease of authoring.

Allowing both short names and longer names based on URIs is indeed a 
good compromise, which I support. But I'm not convinced that 
per-language registries for short names are a good idea.

> And since we already have this flexibility, in my opinion the key
> priority is therefore not a centralised registry, but to provide a way
> for authors to share short-form 'tokens' across languages [1]. This
> would provide a way that people can mark up documents with RDFa in a
> kind of Microformats-style, but without having to go through the
> central registry approach.
> ...

Any new syntax will have to compete for followers with existing systems 
like RDFa, DC-HTML, RDFa, or (gasp) "microdata". So I personally think 
it makes more sense to get RDFa specified for HTML the way it is (using 
xmlns-based prefixes).

BR, Julian
Received on Tuesday, 26 May 2009 11:44:53 UTC

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