xml-dev - Re: Empty Complex Type; Mixed Content Type

[Martin Gudgin <marting@develop.com>]

Yes, you are correct, the <restriction> element can be ommited because the
anyType is being implicitly restricted.

One further wrinkle that we're trying to nail down right now, you might need
an empty <sequence> element to show empty content;

 <xsd:element name="internationalPrice">
  <xsd:complexType>
   <xsd:complexContent>
     <xsd:sequence/>
     <xsd:attribute name="currency" type="xsd:string"/>
     <xsd:attribute name="value"    type="xsd:decimal"/>
   </xsd:complexContent>
  </xsd:complexType>
 </xsd:element>

the reason we can't be certain right now is that the editor of the spec is
working through all the decisions we made with respect to the spec and
hasn't finished chasing that one down yet. Putting in the empty sequence
will never be wrong, but it *might* be optional, I'll keep you posted.

Martin Gudgin

----- Original Message -----
From: "Ramesh Gupta" <ramesh@eNode.com>
To: <xml-dev@xml.org>
Sent: Monday, October 02, 2000 5:42 AM
Subject: Re: Empty Complex Type; Mixed Content Type


> What you're saying makes sense, but the question then changes from "Is
> restriction correct in this case?" to "Must restriction be explicitly
> specified?" In other words, would the following be OK?
>
> <xsd:element name="internationalPrice">
>  <xsd:complexType>
>   <xsd:complexContent>
>     <xsd:attribute name="currency" type="xsd:string"/>
>     <xsd:attribute name="value"    type="xsd:decimal"/>
>   </xsd:complexContent>
>  </xsd:complexType>
> </xsd:element>
>
> I think this should be legal too, and convey the same amount of
information
> as the example in the Primer, no? Restriction of xsd:anyType would be
> implicit in such a type definition, as it is in other cases, right?
>
> Thanks again for clarifying.
>
> Ramesh
>
> on 10/1/00 2:26 PM, Martin Gudgin at marting@develop.com wrote:
>
> > After further study and converse with other WG members I must retract my
> > earlier assertion about the example in the XML Schema Part 0 - Primer[1]
> >
> > The example in the Primer ( shown below ) is correct. An explanation of
why
> > seems to be in order...
> >
> > <xsd:element name="internationalPrice">
> >   <xsd:complexType>
> >       <xsd:complexContent>
> >           <xsd:restriction base="xsd:anyType">
> >               <xsd:attribute name="currency" type="xsd:string"/>
> >               <xsd:attribute name="value"    type="xsd:decimal"/>
> >           </xsd:restriction>
> >       </xsd:complexContent>
> >   </xsd:complexType>
> > </xsd:element>
> >
> > It might seem strange to add attributes during a restriction but really
it's
> > no different from the element case:
> >
> > <complexType name='foo'>
> >   <element name='bar' type='string' />
> >   <element name='baz' type='string' />
> > </complexType>
> >
> > is implicitly a restriction or the ur-type ( xsd:anyType is implicitly
the
> > base ).
> >
> > The ur-type also contains an <xsd:anyAttribute> so the similar attribute
> > case would be;
> >
> > <complexType name='foo'>
> >   <attribute name='bar' type='string' />
> >   <attribute name='baz' type='string' />
> > </complexType>
> >
> > Here we are restricting the valid attributes from any attributes to a
bar
> > attribute and a baz attribute.
>