Example: Constrain a domain module

In this scenario, an information architect wants to use only a subset of the elements defined in the highlighting domain. She wants to use <b> and <i,> but not <line-through>, <overline>, <sup>, <sup>, <tt>, or <u>. She wants to integrate this constraint into the document-type shell for task.

She creates reducedHighlightingDomainConstraint.mod, where "reduced" is a string that characterizes the constraint.

She adds the following content to reducedHighlightingDomainConstraint.mod:

<!-- ============================================================= -->
<!--      CONSTRAINED HIGHLIGHTING DOMAIN ENTITIES                 -->
<!-- ============================================================= -->

<!ENTITY HighlightingDomain-constraints     
  "(topic hi-d basic-HighlightingDomain-c)"
>

<!ENTITY % HighlightingDomain-c-ph     "b | i"                 >

She then integrates the constraint module into her company-specific, document-type shell for the task topic by adding the following section directly before the "DOMAIN ENTITY DECLARATIONS" comment:

<!-- ============================================================= -->
<!--                    DOMAIN CONSTRAINT INTEGRATION              -->
<!-- ============================================================= -->

<!ENTITY % HighlightingDomain-c-dec  
  PUBLIC "-//ACME//ENTITIES DITA Highlighting Domain Constraint//EN" 
  "acme-HighlightingDomainConstraint.mod"
>%basic-HighlightingDomain-c-dec;

In the "DOMAIN EXTENSIONS" section, she replaces the parameter entity for the highlighting domain with the parameter entity for the constrained highlighting domain:

<!ENTITY % ph           "ph |
                         %HighlightingDomain-c-ph; |
                         %sw-d-ph; | 
                         %ui-d-ph;
                        ">

She then adds the constraint to the list of domains and constraints that need to be included in the value of the @domains attribute for <task>:

<!-- ============================================================= -->
<!--                    DOMAINS ATTRIBUTE OVERRIDE                 -->
<!-- ============================================================= -->

<!ENTITY included-domains 
                          "&task-att;
                           &hi-d-att; 
                           &indexing-d-att;
                           &pr-d-att; 
                           &sw-d-att;
                           &ui-d-att;
                           &taskbody-constraints;
                           &HighlightingDomain-constraints;
  "
>

After updating the catalog.xml file to include the new constraints file, her work is done.