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RE: [XML Schema 1.1] Many questions about openContent

From: Michael Kay <mike@saxonica.com>
Date: Fri, 29 May 2009 16:55:26 +0100
To: "'Costello, Roger L.'" <costello@mitre.org>, <xmlschema-dev@w3.org>
Message-ID: <E98C7851F71C4B309CC304B29BE46E90@Sealion>
There are no constraints on how many elements you can have matching the open
content. So, if you like, it's effectively minOccurs="0"
maxOccurs="unbounded".

Regards,

Michael Kay
http://www.saxonica.com/
http://twitter.com/michaelhkay 



> -----Original Message-----
> From: xmlschema-dev-request@w3.org 
> [mailto:xmlschema-dev-request@w3.org] On Behalf Of Costello, Roger L.
> Sent: 29 May 2009 16:50
> To: 'xmlschema-dev@w3.org'
> Subject: RE: [XML Schema 1.1] Many questions about openContent
> 
>  
> Thanks Michael.
> 
> So the <any> element within an <openContent> is always 
> (effectively) minOccurs="1" and maxOccurs="1". Correct?
> 
> That is, it is effectively this:
> 
> <element name="Book">
>     <complexType>
>         <openContent mode="interleaved">
>             <any minOccurs="1" maxOccurs="1" />
>         </openContent>
>         <sequence>
>             <element name="Title" type="string"/>
>             <element name="Author" type="string" />
>             <element name="Date" type="string"/>
>             <element name="ISBN" type="string"/>
>             <element name="Publisher" type="string"/>
>         </sequence>
>     </complexType>
> </element>
> 
> Correct?
> 
> Now, what does that mean?
> 
> Does it mean that 1 new element *must* be inserted into the 
> <sequence> content model? Or, does it mean that:
> 
>    Before the <Title> element there *must* be 1 new element, and
>    Before the <Author element there *must* be 1 new element, and
>    Before the <Date> element there *must* be 1 new element, and
>    Before the <ISBN> element there *must* be 1 new element, and
>    Before the <Publisher> element there *must* be 1 new element, and
>    After the <Publisher> element there *must* be 1 new element.
> 
> 
> And what about mode="suffix":
> 
> <element name="Book">
>     <complexType>
>         <openContent mode="suffix">
>             <any />
>         </openContent>
>         <sequence>
>             <element name="Title" type="string"/>
>             <element name="Author" type="string" />
>             <element name="Date" type="string"/>
>             <element name="ISBN" type="string"/>
>             <element name="Publisher" type="string"/>
>         </sequence>
>     </complexType>
> </element>
> 
> Does this mean that 1 new element must always be placed at 
> the bottom of the <sequence> content model (after the 
> <Publisher> element)?
> 
> /Roger
> 
> 
> 
> > -----Original Message-----
> > From: Michael Kay [mailto:mike@saxonica.com]
> > Sent: Friday, May 29, 2009 11:39 AM
> > To: Costello, Roger L.; xmlschema-dev@w3.org
> > Subject: RE: [XML Schema 1.1] Many questions about openContent
> > 
> > 
> > On the first question, the schema component model for open content 
> > does not include a minOccurs and maxOccurs value (the {open 
> content} 
> > property is a wildcard, not a wildcard particle). As far as 
> I can see, 
> > it is permitted to specify these values in the XML 
> representation, but 
> > they are ignored.
> > Perhaps they should not be allowed: I'll raise a bug to 
> propose this.
> > 
> > On the second question, mode="none" is used in the same way as 
> > use="prohibited" on attributes, to suppress inheritance of 
> openContent 
> > in a type that would otherwise acquire it automatically.
> > 
> > Regards,
> > 
> > Michael Kay
> > http://www.saxonica.com/
> > http://twitter.com/michaelhkay
> > 
> >  
> > 
> > > -----Original Message-----
> > > From: xmlschema-dev-request@w3.org
> > > [mailto:xmlschema-dev-request@w3.org] On Behalf Of
> > Costello, Roger L.
> > > Sent: 29 May 2009 16:23
> > > To: 'xmlschema-dev@w3.org'
> > > Subject: [XML Schema 1.1] Many questions about openContent
> > > 
> > > 
> > > Hi Folks,
> > > 
> > > Here is an example of declaring a <Book> element with 
> open content:
> > > 
> > > <element name="Book">
> > >     <complexType>
> > >         <openContent mode="interleaved">
> > >             <any minOccurs="..." maxOccurs="..." />
> > >         </openContent>
> > >         <sequence>
> > >             <element name="Title" type="string"/>
> > >             <element name="Author" type="string" />
> > >             <element name="Date" type="string"/>
> > >             <element name="ISBN" type="string"/>
> > >             <element name="Publisher" type="string"/>
> > >         </sequence>
> > >     </complexType>
> > > </element>
> > > 
> > > Notice that I left unspecified the value of minOccurs and 
> maxOccurs 
> > > on the <any> element.
> > > 
> > > If I specify minOccurs="0" and maxOccurs="1" does it mean 
> that 0-1 
> > > new elements can be inserted into the <sequence> content 
> model? Or, 
> > > does it mean that:
> > > 
> > >    Before the <Title> element there can be 0-1 new elements, and
> > >    Before the <Author element there can be 0-1 new elements, and
> > >    Before the <Date> element there can be 0-1 new elements, and
> > >    Before the <ISBN> element there can be 0-1 new elements, and
> > >    Before the <Publisher> element there can be 0-1 new 
> elements, and
> > >    After the <Publisher> element there can be 0-1 new elements.
> > > 
> > > If I specify minOccurs="1" and maxOccurs="1" does it mean 
> that 1 new 
> > > element must be inserted into the <sequence> content 
> model? Or, does 
> > > it mean that:
> > > 
> > >    Before the <Title> element there must be 1 new element, and
> > >    Before the <Author element there must be 1 new element, and
> > >    Before the <Date> element there must be 1 new element, and
> > >    Before the <ISBN> element there must be 1 new element, and
> > >    Before the <Publisher> element there must be 1 new element, and
> > >    After the <Publisher> element there must be 1 new element.
> > > 
> > > If I specify minOccurs="0" and maxOccurs="unbounded" does it mean 
> > > that 0-unbounded new elements can be inserted into the <sequence> 
> > > content model? Or, does it mean that:
> > > 
> > >    Before the <Title> element there can be 0-unbounded 
> new elements, 
> > > and
> > >    Before the <Author element there can be 0-unbounded 
> new elements, 
> > > and
> > >    Before the <Date> element there can be 0-unbounded new 
> elements, 
> > > and
> > >    Before the <ISBN> element there can be 0-unbounded new 
> elements, 
> > > and
> > >    Before the <Publisher> element there can be 0-unbounded new 
> > > elements, and
> > >    After the <Publisher> element there can be 0-unbounded new 
> > > elements.
> > > 
> > > 
> > > Next, suppose I change the mode to 'suffix':
> > > 
> > > <element name="Book">
> > >     <complexType>
> > >         <openContent mode="suffix">
> > >             <any minOccurs="..." maxOccurs="..." />
> > >         </openContent>
> > >         <sequence>
> > >             <element name="Title" type="string"/>
> > >             <element name="Author" type="string" />
> > >             <element name="Date" type="string"/>
> > >             <element name="ISBN" type="string"/>
> > >             <element name="Publisher" type="string"/>
> > >         </sequence>
> > >     </complexType>
> > > </element>
> > > 
> > > I believe mode="suffix" means that new elements must always be 
> > > placed at the bottom of the <sequence> content model (after the 
> > > <Publisher> element). Correct?
> > > 
> > > If I specify minOccurs="0" and maxOccurs="1" does it mean 
> that 0-1 
> > > new elements can be inserted at the bottom of the 
> <sequence> content 
> > > model?
> > > 
> > > If I specify minOccurs="1" and maxOccurs="1" does it mean 
> that 1 new 
> > > element must be inserted at the bottom of the <sequence> content 
> > > model?
> > > 
> > > If I specify minOccurs="0" and maxOccurs="unbounded" does it mean 
> > > that 0-unbounded new elements can be inserted at the 
> bottom of the 
> > > <sequence> content model?
> > > 
> > > 
> > > Lastly, suppose I change the mode to 'none':
> > > 
> > > <element name="Book">
> > >     <complexType>
> > >         <openContent mode="none">
> > >             <any minOccurs="..." maxOccurs="..." />
> > >         </openContent>
> > >         <sequence>
> > >             <element name="Title" type="string"/>
> > >             <element name="Author" type="string" />
> > >             <element name="Date" type="string"/>
> > >             <element name="ISBN" type="string"/>
> > >             <element name="Publisher" type="string"/>
> > >         </sequence>
> > >     </complexType>
> > > </element>
> > > 
> > > What does mode="none" mean? Does it mean:
> > > 
> > >     You cannot insert new elements into the <sequence>
> > content model.
> > > 
> > > How is it different from this (no openContent specified):
> > > 
> > > <element name="Book">
> > >     <complexType>
> > >         <sequence>
> > >             <element name="Title" type="string"/>
> > >             <element name="Author" type="string" />
> > >             <element name="Date" type="string"/>
> > >             <element name="ISBN" type="string"/>
> > >             <element name="Publisher" type="string"/>
> > >         </sequence>
> > >     </complexType>
> > > </element>
> > > 
> > > Are they the same? If they are, why have mode="none"? What's its 
> > > value?
> > > 
> > > /Roger
> > 
> > 
Received on Friday, 29 May 2009 15:56:01 GMT

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