- From: Paul Kiel <paul@hr-xml.org>
- Date: Tue, 11 Feb 2003 16:11:45 -0500
- To: "Morris Matsa" <mmatsa@us.ibm.com>
- Cc: <xmlschema-dev@w3.org>
I think you are right Morris - that is where I ended up. To the human eye, the difference is not particularly meaningful (date2 will always follow date1 - if they both exist) - but to the parser a difference is a difference and it doesn't matter how big or small. So [{date1, date2}] and [{date1}, {date2}] are two different contents to it. The first is one sequence of two existing elements. The second is two sequences - where only date1 exists in the first sequence and only date2 exists in the second sequence. Paul ----- Original Message ----- From: "Morris Matsa" <mmatsa@us.ibm.com> To: "Paul Kiel" <paul@hr-xml.org> Cc: <xmlschema-dev@w3.org> Sent: Tuesday, February 11, 2003 3:52 PM Subject: Re: ambiguous content model - yea or nay? > > > > I believe that it is an ambiguous content model, and it is a legal schema > component. > > To see that it is ambiguous, consider the instance: (assume dates are > legal) > <element> > <AvailabilityStartDate>date1</AvailabilityStartDate> > <AvailabilityEndDate>date2</AvailabilityEndDate> > </element> > > Which list of sequences did you mean? It could be: > {{date1, date2}}, or {{date1}, {date2}}, or {{}, {}, {}, {date1}, {}, > {date2}}, etc. > > Thus it is an ambiguous content model. > > It is a legal schema component because looking at each tag it is either > "Start" or "End" and you immediately and unambiguously know which particle > in the schema to validate against. It's the "Unique _Particle_ Attribution > Constraint". > > > "Paul Kiel" <paul@hr-xml.org>@w3.org on 02/11/2003 02:36:39 PM > > Sent by: xmlschema-dev-request@w3.org > > > To: <xmlschema-dev@w3.org> > cc: > Subject: ambiguous content model - yea or nay? > > > > > > Question all, > > I am getting an "ambiguous content model" error when validating an instance > conforming to this schema: > <xsd:complexType> > <xsd:sequence maxOccurs="unbounded"> > <xsd:element name="AvailabilityStartDate" type > ="AnyDateTimeNkType" minOccurs="0"/> > <xsd:element name="AvailabilityEndDate" type="AnyDateTimeNkType" > minOccurs="0"/> > </xsd:sequence> > </xsd:complexType> > > I only get the error from 1 of 5 parsers/tools that I validate against. > And only when validating the instance (the schema validates just fine with > that same tool). > > The more I looked at it, the more it seemed "technically" true but I wasn't > sure. > > (For the record, this is a bug fix - I plan on eliminating the maxOccurs > attribute on the sequence.) > > Curiously, > > Paul Kiel > HR-XML Consortium > > > > > > >
Received on Tuesday, 11 February 2003 16:09:23 UTC