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Re: redundant mixed="true" required?

From: Eddie Robertsson <erobertsson@allette.com.au>
Date: Mon, 26 Aug 2002 17:37:22 +1000
Message-ID: <3D69DAB2.5030008@allette.com.au>
To: Masayasu Ishikawa <mimasa@w3.org>
CC: xmlschema-dev@w3.org

Hi,

>Suppose that I have a schema like this:
>
><xs:schema version="1.0"
>    xmlns:xs="http://www.w3.org/2001/XMLSchema"
>    targetNamespace="http://example.com/test"
>    xmlns:test="http://example.com/test">
>
>  <xs:attributeGroup name="attrs">
>    <xs:attribute name="id" type="xs:ID"/>
>    <xs:attribute name="class" type="xs:NMTOKENS"/>
>  </xs:attributeGroup>
>
>  <xs:complexType name="mixed" mixed="true">
>    <xs:choice minOccurs="0" maxOccurs="unbounded">
>      <xs:element ref="test:a"/>
>      <xs:element ref="test:b"/>
>    </xs:choice>
>  </xs:complexType>
>
>  <xs:element name="root">
>    <xs:complexType>
>      <xs:complexContent>
>        <xs:extension base="test:mixed">
>          <xs:attribute name="id" type="xs:ID"/>
>        </xs:extension>
>      </xs:complexContent>
>    </xs:complexType>
>  </xs:element>
>
>  <xs:element name="a">
>    <xs:complexType>
>      <xs:complexContent>
>        <xs:extension base="test:mixed">
>          <xs:attributeGroup ref="test:attrs"/>
>        </xs:extension>
>      </xs:complexContent>
>    </xs:complexType>
>  </xs:element>
>
>  <xs:element name="b">
>    <xs:complexType>
>      <xs:complexContent>
>        <xs:extension base="test:mixed">
>          <xs:attributeGroup ref="test:attrs"/>
>        </xs:extension>
>      </xs:complexContent>
>    </xs:complexType>
>  </xs:element>
>
></xs:schema>
>
>And an instance would be something like this:
>
><root xmlns="http://example.com/test">
>  ccc<a>aaa<b>bbb</b>aaa</a>ccc<b>bbb<a>aaa</a>bbb</b>ccc
></root>
>
>MSV (20020414), Xerces-J 2.0.2 and XML Spy 4.4 reported no problem,
>but XSV (online version, 1.203.2.47.2.4.2.11/1.106.2.25.2.3) complained
>like this:
>
>    Invalid per cvc-complex-type.1.2.3: text not allowed: | ccc|
>
I tested this with MSXML SP1 as well and it also reports this as an 
error. However I believe that this is a correct schema and instance and 
XSV and MSXML4 are wrong here. Section 3.2.1 [1] reads (Complex Type 
Definition with complex content* Schema Component*):

{content type}
The appropriate case among the following:
1 If the <restriction> alternative is chosen, then the appropriate case 
among the following:
1.1 If one of the following is true
1.1.1 There is no <group>, <all>, <choice> or <sequence> among the 
[children];
1.1.2 There is an <all> or <sequence> among the [children] with no 
[children] of its own excluding <annotation>;
1.1.3 There is a <choice> among the [children] with no [children] of its 
own excluding <annotation> whose minOccurs[attribute] has the ·actual 
value· 0; , then empty;
1.2 otherwise a pair consisting of
1.2.1 the appropriate case among the following:
1.2.1.1 If the mixed [attribute] is present on <complexContent>, then 
mixed if its ·actual value· is true, otherwise elementOnly;
1.2.1.2 If the mixed [attribute] is present on <complexType> and its 
·actual value· is true, then mixed;
1.2.1.3 otherwise elementOnly.
1.2.2 The particle corresponding to the <all>, <choice>, <group> or 
<sequence> among the [children].
2 If the <extension> alternative is chosen, then [Definition:]  let the 
explicit content be empty if any of the sub-clauses of clause 1.1 above 
applies, otherwise the particle corresponding to the <all>, <choice>, 
<group> or <sequence> among the [children], and then take the 
appropriate case among the following:
2.1 If the ·explicit content· is empty, then the {content type} of the 
type definition ·resolved· to by the ·actual value· of the base [attribute]
...

In the example we have the following extension:

<xs:element name="root">
  <xs:complexType>
    <xs:complexContent>
      <xs:extension base="test:mixed">
        <xs:attribute name="id" type="xs:ID"/>
      </xs:extension>
    </xs:complexContent>
  </xs:complexType>
</xs:element>

Since this is an extension this will match clause 2 in the above section 
of the spec. This clause says that the explicit content of the derived 
type is empty if any of the sub-clauses of clause 1.1 applies. Looking 
at 1.1.1 above we see that this is a match because we don't have 
<group>, <all>, <choice> or <sequence> among the [children] of the 
extension element. Since the explicit content is empty we have a match 
in 2.1 which specifies the content type of the derived type to be the 
content type of the base type. Since the content type of the base type 
is mixed the content type of the derived type should be mixed as well.

>If I change each element declaration like the following, XSV doesn't
>complain anymore.
>
>  <xs:element name="root">
>    <xs:complexType mixed="true">
>      <xs:complexContent>
>        <xs:extension base="test:mixed">
>          <xs:attribute name="id" type="xs:ID"/>
>        </xs:extension>
>      </xs:complexContent>
>    </xs:complexType>
>  </xs:element>
>
>What's/who's wrong?
>
This shouldn't be necessary. XSV and MSXML are wrong.

Cheers,
/Eddie
Received on Monday, 26 August 2002 03:37:43 GMT

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