formal terminology

[Erik Hennum <ehennum@us.ibm.com>]

Esteemed OASIS DITA Committee Members:

Arising out of the review of the DITA introduction at Tuesday's meeting, I took an action item to provide a more formal terminology.

Bruce Esrig and I have been working on that since Tuesday. The results are appended for your consideration.

Many thanks to Bruce for his clarity, insight, and dedication.


Erik Hennum
ehennum@us.ibm.com


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At the model level, DITA has:

Element type - Defines the structure and semantics for a fragment of content.

Specialized element type - Defines an element type as a semantic refinement of a base element type. The content allowed by the specialized element type must be a subset of or identical to the content allowed by the base element type.

Topic type - An element type that defines a complete unit of content. The topic type provides the root element and, through contained element types, substructure for the topic instances.

Map type - An element type that defines a set of relationships for topic instances. The map type provides the root element and, through contained element types, substructure for the map instances. The map substructure provides hierarchy, group, and matrix organization of references to topic instances.

Information type - An element that defines a unit of information. A topic type or map type.

Type module - Defines a collection of element types. A type module has a dependency on the type modules that, for its specialized element types, provide the base element types.

Topic type module - A type module that collects a topic element type and its substructure element types.

Map type module - A type module that collects a map element type and its substructure element types.

Domain type module - A type module that collects element types defined for a subject-matter area. These element types don't belong to any one information type but, instead, can be used within the instances of many topic and map types.

Type vocabulary - Integrates type modules to define a set of element types that is complete for a descriptive purpose. The type vocabulary also controls nesting of topic instances.


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At the declaration level, DITA has:

Element declaration - The representation within a syntactic scheme (such as DTD, XML Schema, or Relax NG) for an element type.

Declaration module - The representation within a syntactic scheme for a type module.

Topic declaration module - The representation within a syntactic scheme for a topic type module.

Map declaration module - The representation within a syntactic scheme for a map type module.

Domain declaration module - The representation within a syntactic scheme for a domain type module.

Vocabulary declaration - The representation within a syntactic scheme for a type vocabulary. The vocabulary declaration includes and assembles declaration modules.


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At the instance level, DITA has:

Element instance - An occurrence of an element type in a document.

Topic instance - An occurrence of a topic type in a document.

Map instance - An occurrence of a map type in a document.

Document instance - A document whose meaning and validity are determined by a type vocabulary.