Re: [xml-dev] Victory has been declared in the schema wars ...

[Jirka Kosek <jirka@kosek.cz>]

Henri Sivonen wrote:

> I think not having a normative schema for HTML5 is a very good idea.

I don't think so.

> None of the current schema languages (not even Schematron) are adequate
> for expressing all the conformance requirements of HTML5. Experience has
> shown that people become too schema-focused if there is a normative
> schema: DTDs aren't adequate for expressing the conformance requirements
> of HTML 4.01, but still people behave as though they had checked for
> conformance when they have validated against a DTD.

I think that problem is in education here -- it is not a big deal to
show and explain difference between valid and conformant document.

> Still, HTML5 can be counted as a bullet point in favor of the RELAX NG
> camp. The only schema for HTML5 in the works is a RELAX NG (Compact
> Syntax) schema with companion Schematron assertions (
> http://syntax.whattf.org/ ). A conformance checker for HTML5 requires
> non-schema checking code to fill the gaps that RELAX NG and Schematron
> can't fill (conveniently or at all). For example,
> http://hsivonen.iki.fi/validator/html5/ checks for table cell overlap in
> Java code--not in RNG, XSD or Schematron.

Even with custom Java validation code you can't get 100% coverage. Many
requirements in HTML specification are too soft and have to be
interpreted by humans.

> A lot of people use XSD for data binding. RNG doesn't do data binding
> *by design*, so telling those people to use RNG for data binding doesn't
> seem to help.

RNG can do databinding and there are many tools that implement this. And
if you want do databinding you probably do not have ambiguous schemas.

On its latest meeting, RELAX NG Technical Committee was discussing
whether RELAX NG 1.0 should be improved and developed in future
(http://lists.oasis-open.org/archives/relax-ng/200611/msg00022.html). If
you think that RNG should have better support for data-binding you can
submit this request to TC.

				Jirka

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