如何在基于Docbook标签的XSD中包含MathML标签？

Question

I'm working on an XSD that is based on a subset of Docbook 5 tags. Here is a very small part of this XSD with a few tags just for illustrate de problem:

<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns="http://docbook.org/ns/docbook" targetNamespace="http://docbook.org/ns/docbook" elementFormDefault="qualified" attributeFormDefault="unqualified">
<xs:import namespace="http://www.w3.org/1999/xlink" schemaLocation="xlink.xsd"/>
<xs:import namespace="http://www.w3.org/XML/1998/namespace" schemaLocation="xml.xsd"/>
<xs:element name="book">
    <xs:annotation>
        <xs:documentation>Root element</xs:documentation>
    </xs:annotation>
    <xs:complexType>
        <xs:sequence>
            <xs:element ref="chapter" maxOccurs="unbounded"/>
        </xs:sequence>
        <xs:attribute ref="xml:lang" use="required"/>
    </xs:complexType>
</xs:element>
<xs:element name="chapter">
    <xs:complexType>
        <xs:sequence>
            <xs:element ref="informalequation" maxOccurs="unbounded"/>
        </xs:sequence>
        <xs:attribute ref="xml:lang" use="required"/>
        <xs:attribute ref="xml:id" use="required"/>
    </xs:complexType>
</xs:element>
<xs:element name="informalequation">
    <xs:complexType>
        <xs:attribute ref="xml:id"/>
        <xs:attribute name="condition" use="required">
            <xs:simpleType>
                <xs:restriction base="xs:string">
                    <xs:enumeration value="block"/>
                    <xs:enumeration value="inline"/>
                </xs:restriction>
            </xs:simpleType>
        </xs:attribute>
    </xs:complexType>
</xs:element>

Right now, element <informalequation> has no content, only attributes. What I would like to do is put inside it an equation in MathML format such as:

<math display='block'>
 <mrow>
  <msqrt>
   <mn>2</mn>
  </msqrt>
 </mrow>
</math>

And here is the problem... I don't know how to do that because MathML tags are not included in Docbook... I'm using Altova XMLSpy 2011 Enterprise Edition to create my XSD. I've downloaded MathML 3 XSD from http://www.w3.org/Math/XMLSchema/ but I don't know what to do next. Does anyone know how to do it and get a valid XSD so I can create an XML based on it with this structure?:

<?xml version="1.0" encoding="UTF-8"?>
<book xml:lang="en" version="5.0" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink">
<chapter xml:lang="en" xml:id="1">
    <informalequation condition="block">
        <math display='block'>
            <mrow>
                <msqrt>
                    <mn>2</mn>
                </msqrt>
            </mrow>
        </math>
    </informalequation>
</chapter>

I'll appreciate any help.

Thanks!

Answer 1

Firstly you want the math to be in the mathml namespace so

 <math display='block' xmlns="http://www.w3.org/1998/Math/MathML">

Then I think you can just replace <xs:simpleType> by

     <xs:sequence>
        <xs:element ref="mml:math" xmlns:mml="http://www.w3.org/1998/Math/MathML"/>
    </xs:sequence>

and arrange in your validator that the mathml names[ace is associated to the MathML schema.

(But I never use XSD, personally I'd just write in RelaxNG and translate:-)