Example: Replace a base element with the domain extensions

Darwin Information Typing Architecture (DITA) Version 1.3 Part 2: Technical Content Edition

OASIS DITA Technical Committee

In this scenario, an information architect wants to remove the ph element but allow the extensions of ph that exist in the highlighting, programming, software, and user interface domains.

  1. The information architect creates an entities file named noPhConstraint.ent, where "no" is a qualifier string that characterizes the constraint.
  2. The information architect adds the following content to noPhConstraint.ent:
    <!-- ============================================================= -->
    <!--      CONSTRAINED HIGHLIGHTING DOMAIN ENTITIES                 -->
    <!-- ============================================================= -->
    <!ENTITY ph-constraints     
      "(topic noPh-ph-c)"
    Note: Because the highlighting and programming domains cannot be generalized without the ph element, this entity must be defined so that there is a separate parenthetical expression that can be included in the domains attribute for the topic.
  3. The information architect then integrates the constraint module into a document-type shell for concept by adding the following section above the "TOPIC ELEMENT INTEGRATION" comment:
    <!-- ============================================================= -->
    <!--                    CONTENT CONSTRAINT INTEGRATION             -->
    <!-- ============================================================= -->
    <!ENTITY % noPh-ph-c-def  
      PUBLIC "-//ACME//ELEMENTS DITA Ph Constraint//EN" 
      "acme-PhConstraint-constraints" "noPhConstraint.ent">
  4. In the "DOMAIN EXTENSIONS" section, the information architect removes the reference to the ph element:
    <!-- Removed "ph | " so as to make <ph> not available, only the domain extensions. -->
    <!ENTITY % ph           "%pr-d-ph; |
                             %sw-d-ph; | 
  5. She then adds the constraint to the list of domains and constraints that need to be included in the value of the domains attribute:
    <!-- ============================================================= -->
    <!--                    DOMAINS ATTRIBUTE OVERRIDE                 -->
    <!-- ============================================================= -->
    <!ENTITY included-domains 
  6. After updating the catalog.xml file to include the new constraints file, the information architect's work is done.