Topic Constraint Module Step 1: Create The Constraint Module File

A DTD-syntax constraint module consists of a single file that contains the overrides for the base elements or attributes.

Constraint modules should be named "qualifiertagnameConstraints.mod" where qualifier is descriptive of the constraints applied and tagname is the topic type, map type, or domain to which the constraint is applied.

Note that a given constraint module can only define constraints for a single topic type, map type, or domain. This ensures that constraint modules map one-to-one with the vocabulary modules they constrain. Likewise, for a given element type or attribute you can have at most one constraint module.

For this tutorial the constraint domain should be called "highlightOnlyTopicConstraint.mod".

Create a directory named "highlightOnlyTopicConstraint" and in that directory create the file highlightOnlyTopicConstraint.mod.

Edit the file highlightOnlyTopicConstraint.mod and add a descriptive header comment:
<?xml version="1.0" encoding="UTF-8"?>
<!-- ======================================
     Constraint Domain: Paragraphs with
     only highlight domain elements.
     Copyright (c) 2010 Your Name Here
     ====================================== -->
<!-- ============ End of constraint module -->