Re: [xml-dev] Perplexing Invalid Schema

[Michael Kay <mike@saxonica.com>]

Posting my reply to the list for completeness... MK

On 11/09/2012 15:44, Michael Kay wrote:
>
> Saxon is rejecting the schema because type X is not a restriction of 
> type Any; it is derived from Any, but some of the derivation steps 
> involve Extension.
>
> I believe this is correct according to the specification.
>
> Section 3.4.6 Constraints on Complex Type Definition Schema Components
>
> tells us that
>
> Schema Component Constraint: Derivation Valid (Restriction, Complex)
>
> must be satisfied in respect of types Z and Item1.
>
> Clause 5.4.2 of this constraint tells us:
>
> The particle of the complex type definition itself must be a ·valid 
> restriction· of the particle of the {content type} of the {base type 
> definition} as defined in Particle Valid (Restriction) (§3.9.6).
>
> Section 3.9.6 Particle Valid (Restriction) tells us the element 
> particle I-Data in Z must be a valid restriction of the element 
> particle I-Data in Item1. Under Particle Restriction OK (Elt:Elt - 
> NameAndTypeOK) we learn in clause 3.2.5 that this means
>
> 3.2.5 R's {type definition} is validly derived given {extension, list, 
> union} from B's {type definition} as defined by Type Derivation OK 
> (Complex) (§3.4.6) or Type Derivation OK (Simple) (§3.14.6), as 
> appropriate.
>
> where R is type X and B is type Any.
>
> This takes us back to 3.4.6 which we execute with the parameter 
> {extension, list, union}.
>
> Rule 1 of 3.4.6 says
>
> 1 If B and D are not the same type definition, then the {derivation 
> method} of D must not be in the subset.
>
> But the subset includes "extension", so derivation by extension isn't 
> allowed; therefore it isn't a valid restriction.
>
> Michael Kay
> Saxonica
>
>
> On 11/09/2012 14:50, Timothy Cook wrote:
>> <?xml version="1.0" encoding="UTF-8"?>
>> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema";
>> elementFormDefault="qualified">
>>      <xs:include schemaLocation="rm-test.xsd"/>
>>
>>      <xs:element name="CCD1" type="Y"/>
>>
>>      <xs:complexType name="Y">
>>          <xs:complexContent>
>>              <xs:restriction base="ccdType">
>>                  <xs:sequence>
>>                      <xs:element name="defin" type="Z"/>
>>                  </xs:sequence>
>>              </xs:restriction>
>>          </xs:complexContent>
>>      </xs:complexType>
>>
>>
>>      <xs:complexType name="Z">
>>          <xs:complexContent>
>>              <xs:restriction base="Item1">
>>                  <xs:sequence>
>>                      <xs:element name="L-data" type="xs:string"
>> fixed="My L string."/>
>>                      <xs:element name="I-data" type="X"/>
>>                  </xs:sequence>
>>              </xs:restriction>
>>          </xs:complexContent>
>>      </xs:complexType>
>>
>>      <xs:complexType name="X">
>>          <xs:complexContent>
>>              <xs:restriction base="DT1-1">
>>                  <xs:sequence>
>>                      <xs:element name="A-data" type="xs:string"
>> fixed="My A string."/>
>>                      <xs:element name="dt-data" type="xs:string"
>> fixed="A dt string."/>
>>                  </xs:sequence>
>>              </xs:restriction>
>>          </xs:complexContent>
>>      </xs:complexType>
>>
>>
>>
>>
>> </xs:schema>
>