Re: extension vs restriction

"Zar Zar Tun" <zarzar@dstc.edu.au> writes:

> What stops a person from changing the entire content of a type through the
> restricting of groups?
> Could you go like this? (which would be against the grain of derivation by
> restriction)
> 
> ...
> 
> <group name="s2r">
> <sequence>
>   <element ref='new_element' minOccurs ='0' maxOccurs='1'/>
>   <element ref='some_other_element' minOccurs ='0' maxOccurs='1'/>
> </sequence>
> </group>
> 
> <complexType name='t3' base='t2' derivedBy='restriction'>
> <sequence>
>   <group ref='s1'/>
>   <group ref='s2r'/>
> </sequence>
> </complexType>
> 
> If not, what is allowable in doing a restriction on groups and group
> components?

Sorry I wasn't clear:  groups just avoid re-typing, they don't bypass
the rules on restriction:  it's the resulting content models which
must satisfy the one-to-one mapping requirements, so your derivation
above would be ruled out.

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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Received on Monday, 11 September 2000 04:29:47 UTC