Re: Extension of xs:simpleContent

Hi Mukul,

Thanks for trying it on Xerces.  It's a validator I don't have.

Motivated by your suggestion I decided to look for an on-line version and 
found the following:

http://validate.openlaboratory.net/

I put in the following files:

----Fail.xsd-----
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">

    <xs:complexType name="DoubleBase">
        <xs:simpleContent>
            <xs:extension base="xs:double">
                <xs:attribute name="DoubleBaseAttr" type="xs:boolean"/>
            </xs:extension>
        </xs:simpleContent>
    </xs:complexType>

    <xs:complexType name="DoubleBaseExtension">
      <xs:complexContent>
            <xs:extension base="DoubleBase">
                <xs:attribute name="DoubleExtensionAttr" type="xs:boolean"/>
            </xs:extension>
        </xs:complexContent>
    </xs:complexType>

    <xs:element name="DoubleElement" type="DoubleBaseExtension"/>

</xs:schema>

----Fail.xml-----
<DoubleElement DoubleExtensionAttr="true" 
DoubleBaseAttr="false">1.5</DoubleElement>

While it reported that the XSD and XML were OK, it displayed the following 
error message.

======
Validation results

Checking first import/include references in schema files:
Fail.xsd: OK
Fail.xml: OK

Running validation process '/usr/bin/DOMPrint'

Errors detected:
Error at file "Fail.xml", line 2, column 69
   Message: No character data is allowed by content model

Instance Fail.xml:
<?xml version="1.0" encoding="UTF-8"?>
<DoubleElement DoubleExtensionAttr="true" 
DoubleBaseAttr="false">1.5</DoubleElement>

======

Does anybody know what an instance should look like if the schema is OK, but 
this instance is wrong?

BTW: I don't know what version of Xerces the page uses.

Thanks,

Pete Cordell
Codalogic Ltd
Interface XML to C++ the easy way using C++ XML
data binding to convert XSD schemas to C++ classes.
Visit http://codalogic.com/lmx/ or http://www.xml2cpp.com
for more info
----- Original Message ----- 
From: "Mukul Gandhi" <[email protected]>
To: "Pete Cordell" <[email protected]>
Cc: <[email protected]>
Sent: Wednesday, November 17, 2010 5:50 PM
Subject: Re: Extension of xs:simpleContent



Hi Pete,
   I believe the schema you've posted is correct (I cross checked with
Xerces too). I think for simpleContent instances, schema component
complexContent can be used technically as well (since simpleContent is
a subset of complexContent).

Though I would have designed the schema type "DoubleBaseExtension"
specified in your example, to use simpleContent rather than
complexContent (as you rightly said too).

On Wed, Nov 17, 2010 at 10:45 PM, Pete Cordell <[email protected]> 
wrote:
> I have a customer who has a schema that extends a simple type double into 
> a
> complex type with simple content, and then as a separate construct extends
> that into a complex type with complex content. They do this along the
> following lines:
>
> <xs:complexType name="DoubleBase">
> <xs:simpleContent>
> <xs:extension base="xs:double">
> <xs:attribute name="DoubleBaseAttr" type="xs:boolean"/>
> </xs:extension>
> </xs:simpleContent>
> </xs:complexType>
>
> <xs:complexType name="DoubleBaseExtension">
> <xs:complexContent>
> <xs:extension base="DoubleBase">
> <xs:attribute name="DoubleExtensionAttr" type="xs:boolean"/>
> </xs:extension>
> </xs:complexContent>
> </xs:complexType>
>
> (To avoid confusion, the intent of the latter is to add the
> DoubleExtensionAttr attribute rather than mandate that you've got
> complexContent.)
>
> My feeling is this is wrong because DoubleBaseExtension should specify
> xs:simpleContent rather than xs:complexContent.
>
> However, XML Spy and Visual Studio seem to accept the above, and the 
> example
> is actually based on a industry consortium schema that specifies similar
> constructs.
>
> So my questions are:
>
> 1) Is the above schema correct or not?
>
> 2) If it is technically incorrect, is it widely occurring (possibly 
> because
> tools fail to pick it up) and therefore worth overlooking this error?
>
> Thanks,
>
> Pete Cordell
> Codalogic Ltd
> Interface XML to C++ the easy way using C++ XML
> data binding to convert XSD schemas to C++ classes.
> Visit http://codalogic.com/lmx/ or http://www.xml2cpp.com
> for more info





-- 
Regards,
Mukul Gandhi