xml-dev - Re: Must DTDs constrain order?

[Eric van der Vlist <vdv@dyomedea.com>]

Tim Bray wrote:
> 
> At 07:36 PM 27/10/00 -0700, Wayne Steele wrote:
> 
> >I have had to deal with this frequently.
> >Here are several choices I've made at different times:
> 
> Here's another one.  Since you're going to have to write
> some code anyhow to validate against business rules, just
> put the content check in there and don't waste your time
> trying to make DTDs do things that aren't cost-effective.

Yes, this is probably the way to go...

I begin to think that XML vocabularies should take example on XML itself
and that when designing a vocabulary one should start by defining the
infoset (the data model), a canonical form (a very strict syntax) before
defining one (or more if needed) "user XML syntax(es)" and canonization
algorithms with reference implementation(s).

In this case, the canonization process would include elements ordering.

It can also include business algorithm as Tim mentioned.

The canonical form being very strict, the canonical algorithm could also
include namespace filtering and prefix rewriting allowing things like
DTD validation of modular multi-namespace XML documents or generation of
semantic (RDF or XLink) metadata.

(Such a process would also facilitate "namespace migration" as recently
discussed on this list about href vs xlink:href or style vs a potential
css:style.)

Eric

> -Tim

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