W3C home > Mailing lists > Public > public-forms@w3.org > July 2007

Re: Schema issue: Order dependence of submission child elements

From: Erik Bruchez <ebruchez@orbeon.com>
Date: Fri, 27 Jul 2007 10:13:13 +0200
Message-ID: <46A9A919.4030509@orbeon.com>
To: "Forms WG (new)" <public-forms@w3.org>

I don't have a solution, not being an absolute schema specialist, but it 
always feels good to point out that with Relax NG, this is extremely 
easy to do and you don't even have to look up a tutorial or a spec! It 
would look like this and be immediately understandable by even somebody 
who has never written any Relax NG:

<interleave>
     <optional>
         <element name="resource">...</element>
     </optional>
     <optional>
         <element name="method">...</element>
     </optional>
     <zeroOrMore>
         <element name="header">...</element>
     </zeroOrMore>
</interleave>

-Erik

John Boyer wrote:
> 
> The issue of ordered children of submission came up on the Wednesday 
> telecon.
> 
> On the telecon it was stated that it was hard in XML schema to specify 
> child elements that were both optional and in a required order.
> 
> I preserved this aspect of submission in the current editor's draft 
> because I do not understand why it is hard, whereas I can easily see it 
> being harder to write a schema that says the child is optional but could 
> appear anywhere in the list of child elements.  It is easy to see how to 
> do it if the schema also allows the child to appear any number of times, 
> but this is not what we want.
> 
> Isn't it just a case of saying that the submission has a resource 
> element with minoccurs=0 then a method element with minoccurs=0 then a 
> header element with minoccurs=0 and maxoccurs=unbounded?
> 
> Is there an easy way to say "In any order, one or zero resource plus one 
> or zero method plus zero or more header"?  
> 
> Cheers,
> John M. Boyer, Ph.D.
> STSM: Lotus Forms Architect and Researcher
> Chair, W3C Forms Working Group
> Workplace, Portal and Collaboration Software
> IBM Victoria Software Lab
> E-Mail: boyerj@ca.ibm.com  
> 
> Blog: http://www.ibm.com/developerworks/blogs/page/JohnBoyer
> 


-- 
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http://www.orbeon.com/
Received on Friday, 27 July 2007 08:13:28 UTC

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