Example: Adding an existing domain attribute to certain elements using DTDs

This section is non-normative.

In this scenario, a company wants to use the @otherprops attribute specialization. However, they want to make the attribute available only on certain elements: <p>, <div>, and <section>.

The DITA architect will need to create an extension module and integrate it into the appropriate document-type shells.

1. The DITA architect creates an expansion module that adds the @otherprops attribute to the selected elements: acme-otherpropsAttExpansion.mod. The expansion module contains the following code:

   <?xml version="1.0" encoding="UTF-8"?>
   
   <!-- Add the otherprops attribute to certain elements -->
   <!ATTLIST p %otherpropsAtt-d-attribute;>
   <!ATTLIST div %otherpropsAtt-d-attribute;>
   <!ATTLIST section %otherpropsAtt-d-attribute;>

   Note that the %otherpropsAtt-d-attribute; is defined in the separate attribute-specialization module that defines the @otherprops attribute.

2. They then update the catalog.xml file to include the expansion module.
3. They integrate the extension module into the applicable document-type shell, after the declaration for the @otherprops attribute-specialization module:

   <!-- ============================================================= -->
   <!--             DOMAIN ATTRIBUTES DECLARATIONS                    -->
   <!-- ============================================================= -->
   ...
   
   <!ENTITY % otherpropsAtt-d-dec
     PUBLIC "-//OASIS//ENTITIES DITA 2.0 Otherprops Attribute Domain//EN"
            "otherpropsAttDomain.ent"
   >%otherpropsAtt-d-dec;
   
   <!ENTITY % otherprops-expansion-e-def  
     PUBLIC "-//ACME//DITA 2.0 Otherprops Expansion//EN" 
            "acme-otherpropsAttExpansion.mod"
     >%otherprops-expansion-e-def;
   
   ...

4. They remove the reference to the @otherprops attribute from the props-attribute-extension entity:

   <!-- ============================================================= -->
   <!--                    DOMAIN ATTRIBUTE EXTENSIONS                -->
   <!-- ============================================================= -->
   
   <!ENTITY % base-attribute-extensions
     ""
   >
   
   <!ENTITY % props-attribute-extensions
     "%audienceAtt-d-attribute;
      %deliveryTargetAtt-d-attribute;
      %otherpropsAtt-d-attribute;
      %platformAtt-d-attribute;
      %productAtt-d-attribute;"
   >

5. They ensure that the included-domains entity contains the @otherprops contribution to the @specializations attribute:

   <!-- ============================================================= -->
   <!--                 SPECIALIZATIONS ATTRIBUTE OVERRIDE            -->
   <!-- ============================================================= -->
   
   <!ENTITY included-domains
                             "&audienceAtt-d-att;
                              &deliveryTargetAtt-d-att;
                              &otherpropsAtt-d-att;
                              &platformAtt-d-att;
                              &productAtt-d-att;"
   >

6. After checking the test topic to ensure that the attribute lists are modified as expected, the work is done.