XSLT, 2nd Edition

Anonymous Types

Everything we’ve done to this point has used anonymous types. That means we used <xs:simpleType> or <xs:complexType>, but we didn’t give those types a name. That was OK for our simple schemas because we didn’t want to reuse those datatypes outside the element in which they were defined. From now on, we’ll give our datatypes a name so we can use them whenever we need to. Here’s the difference between an anonymous type and a named type:

<?xml version="1.0" encoding="UTF-8"?>
<!-- content4.xsd -->
<xs:schema 
  xmlns="http://www.oreilly.com/xslt"
  targetNamespace="http://www.oreilly.com/xslt"
  xmlns:xs="http://www.w3.org/2001/XMLSchema">

  <xs:element name="content4a">
    <xs:complexType>
      <xs:simpleContent>
        <xs:extension base="xs:string">
          <xs:attribute name="color" type="xs:string"/>
        </xs:extension>
      </xs:simpleContent>
    </xs:complexType>
  </xs:element>

  <xs:complexType name="content4b-type">
    <xs:simpleContent>
      <xs:extension base="xs:string">
        <xs:attribute name="color" type="xs:string"/>
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:element name="content4b" type="content4b-type"/>

</xs:schema>

The first element in the schema, <content4a>, uses an anonymous type. The second element has the exact same structure, but it uses the named datatype we created. The difference, of course, is that we can use the named datatype anywhere, while the anonymous type exists only inside the declaration of element <content4a>.