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Re: Dropping RDF mapping from microdata spec

From: Jeni Tennison <jeni@jenitennison.com>
Date: Thu, 28 Jul 2011 18:37:36 +0100
Cc: Richard Cyganiak <richard.cyganiak@deri.org>, Michael Hausenblas <michael.hausenblas@deri.org>, "www-tag@w3.org List" <www-tag@w3.org>
Message-Id: <A44AF431-E957-4106-B279-180189FED549@jenitennison.com>
To: nathan@webr3.org
Nathan,

On 28 Jul 2011, at 17:16, Nathan wrote:
> I want to create a scheme for microdata authors to use, I want it to be machine readable and dereferencable, where's the spec I should follow?


There's no spec for that (so far as I know): if you create a vocabulary, you write a document that explains how the vocabulary works, maybe supply a preview/validation tool like the Google Rich Snippets validation tool if you need to.

There's also (to explain the thinking behind the way microdata works here) no need for automated discovery of such a schema. A consuming application either has hard-wired understanding of the vocabularies that it finds in a page or not. If it doesn't, it must not follow any links (eg the item type) to get any more information in order to understand the vocabulary. I think the rationale there is that if they could, it might lead to a dependence of the behaviour of the application on network connectivity.

Any code that consumes the vocabulary will naturally validate (and interpret, particularly to map to an appropriate data type) to whatever degree is useful.

I don't think that there's anything stopping such a declarative schema language for microdata vocabularies being developed or reusing a validation technology from elsewhere. Actually, Philip Jägenstedt was talking on IRC earlier about possibly generating XML from microdata and then using RELAX NG to validate over it:

  http://krijnhoetmer.nl/irc-logs/whatwg/20110728#l-549

but I'm not sure how serious that suggestion was...

Cheers,

Jeni
-- 
Jeni Tennison
http://www.jenitennison.com
Received on Thursday, 28 July 2011 17:38:09 GMT

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