[examplotron] Re: Rules-based standards (was: Advanced handling of attributes)

Jonathan Lang said:
>
> Eric van der Vlist wrote:
>> Martin Roberts wrote:
>> > Why can't schematron asserts be applied to attributes? On the old
>> > Examplotron, rules could be attribute based.
>>
>> I don't see any really good reason!
>>
>> I *think* that it's part of the feeling that attributes are nothing
>> more than annotations for the elements ti which they belong.
>> This is the price to pay to get Examplotron based on standards and I
>> *think* that it's worth the effort but it's probably something we
>> should discuss in more details!
>
> Perhaps Schematron is the wrong standard to be using for rules-based
> document validation?

I don't think so (see below), but I may be wrong.

> XSLT might be a better choice (especially once
> XSLT 2.0 and XPath 2.0 reach Recommendation status, what with their
> incorporation of namespaces and datatypes);

I wouldn't recommend this. The support of datatypes in XSLT 2.0 and XPath
2.0 relies on W3C XML Schema, what would be the point of Examplotron if
you had to provide a WXS schema?
> I suspect that it's
> possible to view Schematron as a subset of XSLT, and to arrange for a
> transformation from the former to the latter in a fairly
> straightforward manner.

Yes. Most of the implementations of Schematron are done by XSLT
transformations which compile a Schematron schema into a XSLT
transformation which performs the job.
The exceptions are implementations performing directly a Schematron
validation and this is especially intersting for embedding Schematron
rules within schemas. See for instance MSV -Sun's Multi Schema Validator-
ad its Schematron addon:
http://wwws.sun.com/software/xml/developers/multischema/
http://wwws.sun.com/software/xml/developers/schematronaddon/

Relying on Schematron rules embedded in Relax NG means that we can rely on
existing validators such as this one. It's a benefit we would loose if we
replaced them by simple XPath expressions.
Eric

>
> =====
> Jonathan "Dataweaver" Lang
>
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Eric van der Vlist       http://xmlfr.org            http://dyomedea.com
(W3C) XML Schema ISBN:0-596-00252-1 http://oreilly.com/catalog/xmlschema
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