Map Specialization Step 1: Design the Map Element Types

A typical FAQ consists of one or more groups of questions, where each group has a descriptive title. There may be some introductory material that is not itself FAQ questions.

That suggests that an FAQ map needs the following components:

A topicref for referring to individual FAQ questions, e.g. "faq-question"
A topic head type for creating sets of related questions, e.g. "faq-question-set"
Some metadata for the FAQ set as a whole
The ability to refer to generic (non-FAQ question) topics at the start of an FAQ set.

The metadata requirement is handled by the generic metadata for topicrefs and maps (at least for the purpose of this exercise). References to generic topics can be done using unspecialized <topicref>.

That just leaves two element types to be defined for the FAQ map domain:

<faq-question>

Represents the use of a single FAQ question topic. Would normally be used with faq-question topics. Because we've defined the <faq-question> topic type to require short descriptions, it is probably appropriate to set the default value for the @type attribute to "faq-question" so that users are warned if they point to other topic types. Because FAQ questions are explicitly atomic, <faq-question> does not allow subordinate topicrefs.

<faq-question-set>

Creates a group of related FAQ questions. May have an initial generic topic or may itself refer to a non-FAQ-question topic to act as an introduction or to satisfy the need for title-only topics in some processing environments.

The content model is:

(topicmeta?, 
 topicref?, 
 faq-question*)

For the FAQ map type we need the following element types:

<faq-map>

Specializes from <map> and serves as the root of an FAQ publication. It's content model is:

(title,
 topicmeta?,
 keydef*,
 faq-question-set,
 reltable*)

By requiring exactly one <faq-question-set> the map clearly establishes the root of the overall FAQ navigation structure.