[XML-DEV Mailing List Archive Home] [By Thread] [By Date] [Recent Entries] [Reply To This Message]

Re: Non-deterministic content models


relax ng ambiguous
On Wed, 2003-07-16 at 01:51, Bob Foster wrote:
> From: "Eric van der Vlist" <vdv@d...>
> > > I am not sure this technical distinction helps the average schema
> writer.
> > > For example, rewriting an ambiguous schema so it is merely
> non-deterministic
> > > won't help XML Schema users. ;-}
> >
> > This chapter is in a book about Relax NG and its number one goal is to
> > help Relax NG users :-) ...
> 
> Good point. Then you could probably omit that section on rewriting patterns
> so they are deterministic (or is it unambiguous?). RELAX NG users seldom
> need to do that. ;-}

That's right, however using deterministic patterns is a necessary
condition (although not sufficient) to get Relax NG schemas which
translate easily into W3C XML Schema (with the exception of choices of
values which translate into unions of simple types even when they are
ambiguous).

I should probably write some sort of table to summarise all this!
> 
> > > The only case I can think of where the distinction makes any difference
> is
> > > in XML Schema union types, which are allowed to be non-deterministic but
> are
> > > not unambiguous because of the first-match rule.
> >
> > Or for using Relax NG tools (such as MSV) which can derive type
> > information out of unambiguous schemas whether deterministic or not
> > (more precisely, it will provide type information even if the schema is
> > ambiguous but I wouldn't always advise to rely on it).
> 
> That's interesting. I assume you're talking about MSV when used as a SAX2
> filter. What does MSV do when it has multiple valid types, pick one?

Yes, it just picks one.

Thanks

Eric

-- 
Lisez-moi sur XMLfr.
                       http://xmlfr.org/index/person/eric+van+der+vlist/
------------------------------------------------------------------------
Upcoming Schema languages tutorial (registration open):
 - August 4th (Montreal, Canada)  http://makeashorterlink.com/?U28A217A4
------------------------------------------------------------------------
Eric van der Vlist       http://xmlfr.org            http://dyomedea.com
(W3C) XML Schema ISBN:0-596-00252-1 http://oreilly.com/catalog/xmlschema
------------------------------------------------------------------------


PURCHASE STYLUS STUDIO ONLINE TODAY!

Purchasing Stylus Studio from our online shop is Easy, Secure and Value Priced!

Buy Stylus Studio Now

Download The World's Best XML IDE!

Accelerate XML development with our award-winning XML IDE - Download a free trial today!

Don't miss another message! Subscribe to this list today.
Email
First Name
Last Name
Company
Subscribe in XML format
RSS 2.0
Atom 0.3
 

Stylus Studio has published XML-DEV in RSS and ATOM formats, enabling users to easily subcribe to the list from their preferred news reader application.


Stylus Studio Sponsored Links are added links designed to provide related and additional information to the visitors of this website. they were not included by the author in the initial post. To view the content without the Sponsor Links please click here.

Site Map | Privacy Policy | Terms of Use | Trademarks
Free Stylus Studio XML Training:
W3C Member
Stylus Studio® and DataDirect XQuery ™are products from DataDirect Technologies, is a registered trademark of Progress Software Corporation, in the U.S. and other countries. © 2004-2013 All Rights Reserved.