separation of DITA architecture and DITA topic types

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

Esteemed DITA TC:

At the last meeting, we thought there might be value of separating the articulation of the general DITA architectural principles from the characteristics of the DITA topic elements.

As promised, here's a strawman. It can certainly bear refinement to increase the precision but, I hope, makes a start on the separation.


Thanks,



Erik Hennum
ehennum@us.ibm.com


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The DITA Architecture

The key principles of the DITA architecture are as follows:

Content granularity -- Content is organized in self-contained objects that are assembled through containment or by reference into larger and more complex structures.

Strongly typed content -- Content objects are differentiated by class based on well-defined semantics and structure.

Type specialization -- Extensibility is supported through definition of a new element type as both a semantic restriction and structural subset of a base element type such that the new element type is processable by default as the base element type.

Unified type hierarchy -- A set of shared element types provides a base from which all other element types are specialized and to which all other element types can revert.

Type module pluggability -- Element types are collected in type modules that integrate as vocabularies for resue of types and processing.

Separation of interpretation from content -- Presentation or other interpretations of content are applied by processes.

Separation of context from content -- Collection-specific relationships between content and properties of content are specified separately from the content objects with references to the content objects.


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The DITA Topic Type Hierarchy

The DITA topic type hierarchy uses the DITA architecture to address the problem space of human-readable content with topic granularity. The DITA topic type hierarchy provides the following:

* A base type module for topics and their content.

* Through specialization, some core topic types (including concept, reference, and task) and domain type modules (including highlighting, programming, software, and user interface).

* Through pluggable integration, the core vocabularies.

The topic type hierarchy adds the following principle to the principles of the DITA architecture:

Topic orientation - Discrete units of human readable content that cover a specific subject with a specific intent and that can be assembled by containment or reference into websites, help systems, books, specifications, and other information deliverables.