Question

XML schema of XHTML Basic 1.1 (xhtml-basic11-modules-1.xsd file) contains such a redefine:

<xs:redefine schemaLocation="http://www.w3.org/MarkUp/SCHEMA/xhtml-image-1.xsd">
    <xs:annotation>
        <xs:documentation>
    Image module

    Elements defined here:
      * img
        </xs:documentation>
        <xs:documentation source="http://www.w3.org/TR/xhtml-modularization/abstract_modules.html#s_imagemodule"/>
    </xs:annotation>
    <xs:attributeGroup name="xhtml.img.attlist">
        <xs:attributeGroup ref="xhtml.img.attlist">
            <xs:annotation>
                <xs:documentation>
            Original Image Attributes (in Image Module)
         </xs:documentation>
            </xs:annotation>
        </xs:attributeGroup>
    </xs:attributeGroup>
</xs:redefine>

Is that any different from simply including the image module? It seams to me like it doesn’t change anything, but I’m no XML Schema expert.

Answer 1

My initial answer was:

Including the image module would have added everything that is defined there to the schema, whereas using xsd:redefine only the attributeGroup xhtml.img.attlist is imported.

but it is not the case – everything in the referenced schema is included, so the answer appear to be that there is no reason for that xsd:redefine.