> Surely adding a pointless sequence to the choice can't affect the 
outcome,
 > because a pointless sequence is ignored? But I'm not sure at what 
point in
 > the algorithm pointless particles are supposed to be discarded.

The algorithm as it is defined in
http://www.w3.org/TR/xmlschema-1/#cos-particle-restrict
deals with the particles that it checks at some moment, so adding the 
empty sequence should cause the choice not to be ignored and the empty 
sequence will be ignored at the next step when it is checked against an 
empty particle.

 > Anyway, this seems to be one of the cases where the algorithm in 
Schema Part
 > 1 is plain wrong.

I agree, it is not easy to explain why something like in this example is 
not working in XML Schema.

Best Regards,
George
---------------------------------------------------------------------
George Cristian Bina
<oXygen/> XML Editor, Schema Editor and XSLT Editor/Debugger
www.---.com


Michael Kay wrote:
> Surely adding a pointless sequence to the choice can't affect the outco=
me,
> because a pointless sequence is ignored? But I'm not sure at what point=
 in
> the algorithm pointless particles are supposed to be discarded.
> 
> Anyway, this seems to be one of the cases where the algorithm in Schema=
 Part
> 1 is plain wrong.
> 
> Michael Kay 
> http://www.saxonica.com/
> 
> 
>> -----Original Message-----
>> From: xmlschema-dev-request@w... 
>> [mailto:xmlschema-dev-request@w...] On Behalf Of George 
>> Cristian Bina
>> Sent: 13 February 2006 09:34
>> To: richard.liu@u...
>> Cc: xmlschema-dev@w...
>> Subject: Re: E rcase-RecurseLax.1: Group's occurrence range, 
>> (1,unbounded), is not a valid restriction of base group's 
>> occurrence range, (1,1).
>>
>>
>> Hello Richard,
>>
>> Xerces is right to report that error as I read the spec. To have this 
>> correct you need to add an empty sequence as below:
>> <xs:choice>
>>    <xs:group ref="a-Group" maxOccurs="unbounded"/>
>>    <xs:sequence/>
>> </xs:choice>
>> Otherwise the main choice particle is ignored according to
>> http://www.w3.org/TR/xmlschema-1/#cos-particle-restrict
>> See 2, 2.2, 2.2.2, 2.2.2.2.1.
>> ***
>> 2.2 Any pointless occurrences of <sequence>, <choice> or <all> are 
>> ignored, where pointlessness is understood as follows:
>> <choice>
>> One of the following must be true:
>> 2.2.2 All of the following must be true:
>> 2.2.2.1 The particle within which this <choice> appears has 
>> {max occurs} 
>> and {min occurs} of 1.
>> 2.2.2.2 One of the following must be true:
>> 2.2.2.2.1 The <choice>'s {particles} has only one member.
>> ***
>>
>> and the restricted type is equivalent with only
>> <xs:group ref="a-Group" maxOccurs="unbounded"/>
>>
>> that is equivalent with
>>
>> <xs:choice maxOccurs="unbounded">
>>    <xs:element ref="a1"/>
>>    <xs:element ref="a2"/>
>>    <xs:element ref="a3"/>
>> </xs:choice>
>>
>> and this cannot restrict
>>
>> <xs:choice>
>>    <xs:group ref="a-Group" maxOccurs="unbounded"/>
>>    <xs:element ref="b"/>
>> </xs:choice>
>>
>> as the choice here has minOccurs and maxOccurs equal with 1.
>>
>> Best Regards,
>> George
>> ---------------------------------------------------------------------
>> George Cristian Bina
>> <oXygen/> XML Editor, Schema Editor and XSLT Editor/Debugger
>> www.---.com
>>
>>
>> richard.liu@u... wrote:
>>> I have the following W3C XML schema:
>>>
>>> <?xml version="1.0" encoding="UTF-8"?>
>>> <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"  
>>> elementFormDefault="qualified" targetNamespace="http://www.ubs.co=
m/
>>> namespace/wbml-render" xmlns="http://www.ubs.com/namespace/wbml-
>>> render" xmlns:wbr="http://www.ubs.com/namespace/wbml-render">
>>>      <xs:element name="a" type="xs:string"/>
>>>      <xs:element name="a1" type="xs:string"/>
>>>      <xs:element name="a2" type="xs:string"/>
>>>      <xs:element name="a3" type="xs:string"/>
>>>      <xs:element name="b" type="xs:integer"/>
>>>      <xs:group name="a-Group">
>>>          <xs:choice>
>>>              <xs:element ref="a1"/>
>>>              <xs:element ref="a2"/>
>>>              <xs:element ref="a3"/>
>>>          </xs:choice>
>>>      </xs:group>
>>>      <xs:complexType name="groupBaseType">
>>>          <xs:choice>
>>>              <xs:group ref="a-Group" maxOccurs="unbounded"/>
>>>              <xs:element ref="b"/>
>>>          </xs:choice>
>>>      </xs:complexType>
>>>      <xs:complexType name="groupRestrictedType">
>>>          <xs:complexContent>
>>>              <xs:restriction base="groupBaseType">
>>>                  <xs:choice>
>>>                      <xs:group ref="a-Group" maxOccurs="unbounded=
"/>
>>>                  </xs:choice>
>>>              </xs:restriction>
>>>          </xs:complexContent>
>>>      </xs:complexType>
>>>      <xs:complexType name="baseType">
>>>          <xs:choice>
>>>              <xs:element ref="a" maxOccurs="unbounded"/>
>>>              <xs:element ref="b"/>
>>>          </xs:choice>
>>>      </xs:complexType>
>>>      <xs:complexType name="restrictedType">
>>>          <xs:complexContent>
>>>              <xs:restriction base="baseType">
>>>                  <xs:choice>
>>>                      <xs:element ref="a" maxOccurs="unbounded"/>
>>>                  </xs:choice>
>>>              </xs:restriction>
>>>          </xs:complexContent>
>>>      </xs:complexType>
>>> </xs:schema>
>>>
>>> The a-Group is a choice of three elements.  The 
>> groupBaseType is a choice of either one to unbounded many 
>> instances of a-Group, or of the element b.  I want to define 
>> another complex type as a restriction of the groupBaseType.  
>> It should not allow b.
>>> In Oxygen 7 I receive the following two error messages.
>>>
>>> SystemID: /Applications/oxygen/Untitled1.xsd
>>> Location: 21:48
>>> Description: E rcase-RecurseLax.1: Group's occurrence 
>> range, (1,unbounded), is not a valid restriction of base 
>> group's occurrence range, (1,1).
>>> URL: http://www.w3.org/TR/xmlschema-1/#rcase-RecurseLax
>>>
>>> SystemID: /Applications/oxygen/Untitled1.xsd
>>> Location: 21:48
>>> Description: E derivation-ok-restriction.5.4.2: Error for 
>> type 'groupRestrictedType'.  The particle of the type is not 
>> a valid restriction of the particle of the base.
>>> URL: http://www.w3.org/TR/xmlschema-1/#derivation-ok-restriction
>>>
>>> Evidently, based on the second example using baseType and 
>> restrictedType, the error messages pertain to the fact that I 
>> am using a group, but I don't understand what is wrong.  Can 
>> anybody shed light on the error?
>>> Regards,
>>> Richard
>>>
>>> Richard R. Liu
>>> Gundeldingerstr. 171
>>> CH-4053 Basel
>>> Switzerland
>>>
>>> Tel. +41 (61) 361 3275
>>> Email richard.liu@m...
>>>
>>>
>>>
>>> Richard R. Liu
>>> UBS AG
>>> VZA2 - 4.140 IVHS-L2V
>>> Postfach
>>> CH-8098 Z=FCrich
>>> Switzerland
>>>
>>> Tel.  +41-44-238 48 82
>>> Email richard.liu@u...
>>>
>>
> 
> 

From richard.liu@u... Mon