RE: Restriction+choice+substitutionGroup: rcase-RecurseLax insuf ficie nt?

> Substitution group heads are treated as if they were choices, so the
change you've made above sets the explicit (X1|X2) against the implicit
(X1|X2|X3), which is fine.  Or am I missing something?

That being the case, maybe there is a bug with the parser that I am using
(Xerces 2.6.2).  But I'm not convinced; the standard does not explicitly
specify this case under cos-particle-restrict (Schema Component Constraint:
Particle Valid (Restriction)), so I guess I can fault the implementation too
much.  In addition, the rules under cos-particle-restrict (2.2, then 2.2.2
and 2.2.2.2) mean that the inner choice is simplified away.  Leaving the
restriction one of elt <- choice, which is expressly prohibited.

M

-----Original Message-----
From: ht@inf.ed.ac.uk [mailto:ht@inf.ed.ac.uk] 
Sent: Wednesday, 13 April 2005 6:54 PM
To: Thomson, Martin [WOLL:5500:EXCH]
Cc: www-xml-schema-comments@w3.org
Subject: Re: Restriction+choice+substitutionGroup: rcase-RecurseLax
insufficie nt?


"Martin Thomson" <martin.thomson@nortel.com> writes:

>   <xsd:complexType name="A">
>     <xsd:complexContent>
>       <xsd:restriction base="xsd:anyType">
>         <xsd:choice minOccurs="0" maxOccurs="unbounded">
>           <xsd:element ref="X"/>
>           <xsd:element ref="Y"/>
>         </xsd:choice>
>       </xsd:restriction>
>     </xsd:complexContent>
>   </xsd:complexType>

<snip/>

>   <!-- INVALID SCHEMA -->
>   <xsd:complexType name="B">
>     <xsd:complexContent>
>       <xsd:restriction base="A">
>         <xsd:choice minOccurs="0" maxOccurs="unbounded">
>           <xsd:element ref="X1"/>
>           <xsd:element ref="X2"/>
>           <xsd:element ref="Y"/>
>         </xsd:choice>
>       </xsd:restriction>
>     </xsd:complexContent>
>   </xsd:complexType>

Yes, it's irritating that that won't work -- will be fixed in 1.1 we hope.

>   <!-- INVALID SCHEMA -->
>   <xsd:complexType name="B">
>     <xsd:complexContent>
>       <xsd:restriction base="A">
>         <xsd:choice minOccurs="0" maxOccurs="unbounded">
>           <xsd:choice>
>             <xsd:element ref="X1"/>
>             <xsd:element ref="X2"/>
>           </xsd:choice>
>           <xsd:element ref="Y"/>
>         </xsd:choice>
>       </xsd:restriction>
>     </xsd:complexContent>
>   </xsd:complexType>

What's wrong with that one?

Substitution group heads are treated as if they were choices, so the change
you've made above sets the explicit (X1|X2) against the implicit (X1|X2|X3),
which is fine.  Or am I missing something?

ht
-- 
 Henry S. Thompson, HCRC Language Technology Group, University of Edinburgh
                     Half-time member of W3C Team
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