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

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.rng. The expansion module contains the following content:

   <?xml version="1.0" encoding="UTF-8"?>
   <?xml-model href="urn:pubid:oasis:names:tc:dita:rng:vocabularyModuleDesc.rng"
                            schematypens="http://relaxng.org/ns/structure/1.0"?>
   <grammar xmlns="http://relaxng.org/ns/structure/1.0"
     xmlns:a="http://relaxng.org/ns/compatibility/annotations/1.0"
     xmlns:dita="http://dita.oasis-open.org/architecture/2005/"
     datatypeLibrary="http://www.w3.org/2001/XMLSchema-datatypes">
     <div>
       <a:documentation>CONTENT MODEL AND ATTRIBUTE LIST OVERRIDES</a:documentation>
       <include href="urn:pubid:oasis:names:tc:dita:rng:topicMod.rng:2.0">
         <define name="topic-info-types">
           <ref name="topic.element"/>
         </define>
         <define name="p.attributes" combine="interleave">
           <optional>
             <attribute name="otherprops"/>
           </optional>
         </define>
         <define name="div.attributes" combine="interleave">
           <optional>
             <attribute name="otherprops"/>
           </optional>
         </define>
         <define name="section.attributes" combine="interleave">
           <optional>
             <attribute name="otherprops"/>
           </optional>
         </define>
       </include>
     </div>
   </grammar>
   

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, and remove the <include> element for topicMod.rng:

     <div>
       <a:documentation>ELEMENT-TYPE CONFIGURATION INTEGRATION</a:documentation>
         <include href="acme-otherpropsAttExpansion.rng"/>
     </div>
     <div>
       <a:documentation>MODULE INCLUSIONS</a:documentation>
       <include href="urn:pubid:oasis:names:tc:dita:rng:topicMod.rng:2.x"/>
       ...
       <include href="urn:pubid:oasis:names:tc:dita:rng:otherpropsAttDomain.rng:2.0">
       </include>
     </div>

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

     <div>
       <a:documentation>MODULE INCLUSIONS</a:documentation>
         ...
       <include href="urn:pubid:oasis:names:tc:dita:rng:otherpropsAttDomain.rng:2.0">
         <define name="props-attribute-extensions" combine="interleave">
         <empty/>
         </define>
       </include>

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

     <div>
       <a:documentation>SPECIALIZATIONS ATTRIBUTE</a:documentation>
       <define name="specializations-att">
         <optional>
           <attribute name="specializations" a:defaultValue="
                            @props/audience
                            @props/deliveryTarget
                            @props/otherprops
                            @props/platform
                            @props/product"/>
         </optional>
       </define>
     </div>

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