Re: [xml-dev] <all> and minOccurs="0" Problem

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

Radek Wisniewski <rw@datenknecht.de> writes:

> On 14 Sep 2001, Henry S. Thompson wrote:
> 
> > Eddie <eddie@allette.com.au> writes:
> >
> > > > > -----Original Message-----
> > > > > From: Radek Wisniewski [mailto:rw@datenknecht.de]
> > > > > Sent: Thursday, September 13, 2001 10:00 AM
> > > > > To: Martin Gudgin
> > > > > Cc: Radek Wisniewski; xml-dev@lists.xml.org
> > > > > Subject: Re: [xml-dev] <all> and minOccurs="0" Problem
> > > > >
> > > > >
> > > > > Yes, it works fine. But the question remains unanswered: What is the sence
> > > > > of <all minOccurs="0"> attribute?
> > > > > What interesting, I can't deklare such en value in any way because:
> > > > > 1) under <complexType>, element <all> must have both attributes minOccurs
> > > > > and maxOccurs set to 1
> > >
> > > No, the entire <xs:all> group can be optional as well, i.e allowed values for
> > > minOccurs on the xs:all element itself is 0 or 1.
> >
> > Eddie is correct -- the XML Schema WG has agreed a correction here, as
> > two different parts of the REC contradict each other on this point,
> > but the resolution will be that 0 or 1 is allowed.
> 
> OK, is allowed in <all> definition, but if i declare:
> 
> <xs:element name="person">
> 	<xs:complexType>
> 		<xs:all minOccurs="0">
> 			<xs:element name="vorname"/>
> 			<xs:element name="name"/>
> 		</xs:all>
> 	</xs:complexType>
> </xs:element>
> 
> Xerces claims: Error:  cos-all-limited.1.2:  The minOccurs attribute of a
> mod el group with "all" compositor that is part of a pair that is the
> content type of a complex type definition must have the value one.
> The value "0" is incorrect.

> And has right, look at http://www.w3.org/TR/xmlschema-1/#cos-all-limited

As I said, the spec. is self-contradictory -- the schema for schemas
allows 0 in this case.  The WG agreed the contradiction should be
resolved in favour of the sForS and against cos-all-limited, but
Xerces is not wrong to have settled for the other interpretation -- as 
lead editor I apologise for allowing this error to occur.

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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