Re: What is the advantage of RELAX in comparison to Schemas?

[ht@cogsci.ed.ac.uk (Henry S. Thompson)]

Bob Kline <bkline@rksystems.com> writes:

> On Tue, 30 Jan 2001, Inga Eckermann wrote:
> 
> > Hello,
> > 
> > I am new to this list and have read about you mentioning RELAX and
> > TRX. Why do I need these standards? On the RELAX-webpage is written:
> > 
> > Compared with DTD(Document Type Definition), RELAX has new features:
> > 
> >              RELAX grammars are represented in the XML instance syntax 
> >              RELAX borrows rich datatypes of XML Schema Part 2 
> >              RELAX is namespace-aware 
> > 
> > Is it not all included in Schemas as well?
> 
> The most significant difference (from our point of view, at any rate)
> between RELAX and W3C's Schema spec is that the former supports
> context-sensitive content models.  Schematron also supports this
> essential feature, which allows you to specify that a certain type of
> content is allowed for a given element only if the element's parent is
> <X>..</X>, 

This _is_ supported by W3C XML Schema.  It's called local element
declarations.

> or only if the element contains a certain attribute with a
> specific value.  Very disappointing that W3C decided to leave this out.

W3C XML Schema doesn't support this, true.  I'm not a RELAX expert,
but I don't it does either.

ht
-- 
  Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
          W3C Fellow 1999--2001, part-time member of W3C Team
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