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Re: [Bug 8611] Consider adding a full schema to H:TML

From: Henri Sivonen <hsivonen@iki.fi>
Date: Wed, 6 Jan 2010 15:40:16 +0200
Cc: Joe D Williams <joedwil@earthlink.net>, public-html@w3.org
Message-Id: <C38A60A6-AEA5-4051-8850-EF572AA0AC08@iki.fi>
To: Ian Hickson <ian@hixie.ch>
On Jan 6, 2010, at 09:21, Ian Hickson wrote:

>> Is there structure, content models, or combinations of HTML5 that cannot 
>> be modelled by xml schema?
> 
> Insofar as there are structures that cannot be modeled by the XML Infoset, 
> yes. There may also be conformance requirements that cannot be fully 
> expressed by XML Schema itself, but I'm not familiar enough with XML 
> Schema to say whether this is the case or not. Henri might know. (It is 
> the case that SGML DTDs, XML DTDs, RelaxNG, and Schematron all cannot 
> fully express all the machine-checkable conformance requirements of HTML, 
> so I would be surprised if it wasn't also the case for XML Schema.)

XML Schema is less expressive than RELAX NG[1], so XML Schema cannot capture all the document conformance requirements of HTML5, either.

[1] http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.80.4356&rep=rep1&type=pdf

-- 
Henri Sivonen
hsivonen@iki.fi
http://hsivonen.iki.fi/
Received on Wednesday, 6 January 2010 13:40:52 UTC

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