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Architectural specification: All-inclusive edition
The architectural specification portion of the DITA specification outlines the framework of DITA. It contains an overview of DITA markup; addressing; processing; configuration, specialization, generalization, and constraints; as well as information about coding DITA grammar files.
Configuration, specialization, generalization, and constraints
The extension facilities of DITA allow existing vocabulary and constraint modules to be combined to create specific DITA document types. Vocabulary modules also can be specialized to meet requirements that are not satisfied by existing markup.
Generalization
Generalization is the process of reversing a specialization. It converts specialized elements or attributes into the original types from which they were derived.
Attribute generalization
DITA provides a syntax to generalize attributes that have been specialized from the @props or @base attribute. Specialization-aware processors SHOULD process both the specialized and generalized forms of an attribute as equivalent in their values.

Specification URIs
Notices
Introduction to DITA 1.3
The Darwin Information Typing Architecture (DITA) specification defines a set of document types for authoring and organizing topic-oriented information, as well as a set of mechanisms for combining, extending, and constraining document types.
Architectural specification: All-inclusive edition
The architectural specification portion of the DITA specification outlines the framework of DITA. It contains an overview of DITA markup; addressing; processing; configuration, specialization, generalization, and constraints; as well as information about coding DITA grammar files.
- Introduction to DITA
  The Darwin Information Typing Architecture (DITA) is an XML-based architecture for authoring, producing, and delivering topic-oriented, information-typed content that can be reused and single-sourced in a variety of ways. While DITA historically has been driven by the requirements of large-scale technical documentation authoring, management, and delivery, it is a standard that is applicable to any kind of publication or information that might be presented to readers, including interactive training and educational materials, standards, reports, business documents, trade books, travel and nature guides, and more.
- DITA markup
  Topics and maps are the basic building blocks of the Darwin Information Typing Architecture (DITA). Metadata attributes and values can be added to DITA topics and maps, as well as to elements within topics, to allow for conditional publishing and content reuse.
- DITA addressing
  DITA provides two addressing mechanisms. DITA addresses either are direct URI-based addresses, or they are indirect key-based addresses. Within DITA documents, individual elements are addressed by unique identifiers specified on the @id attribute. DITA defines two fragment-identifier syntaxes; one is the full fragment-identifier syntax, and the other is an abbreviated fragment-identifier syntax that can be used when addressing non-topic elements from within the same topic.
- DITA processing
  DITA processing is affected by a number of factors, including attributes that indicate the set of vocabulary and constraint modules on which a DITA document depends; navigation; linking; content reuse (using direct or indirect addressing); conditional processing; branch filtering; chunking; and more. In addition, translation of DITA content is expedited through the use of the @dir, @translate, and @xml:lang attributes, and the <index-sort-as> element.
- Configuration, specialization, generalization, and constraints
  The extension facilities of DITA allow existing vocabulary and constraint modules to be combined to create specific DITA document types. Vocabulary modules also can be specialized to meet requirements that are not satisfied by existing markup.
  - Overview of DITA extension facilities
    DITA provides three extension facilities: configuration, constraint, and specialization. In addition, generalization augments specialization.
  - Configuration
    Configuration enables the definition of DITA document types that include only the vocabulary modules that are required for a given set of documents. There is no need to modify the vocabulary modules. Configurations are implemented as document-type shells.
  - Specialization
    The specialization feature of DITA allows for the creation of new element types and attributes that are explicitly and formally derived from existing types. This facilitates interchange of conforming DITA content and ensures a minimum level of common processing for all DITA content. It also allows specialization-aware processors to add specialization-specific processing to existing base processing.
  - Generalization
    Generalization is the process of reversing a specialization. It converts specialized elements or attributes into the original types from which they were derived.
    - Overview of generalization
      Specialized content can be generalized to any ancestor type. The generalization process can preserve information about the former level of specialization to allow round-tripping between specialized and unspecialized forms of the same content.
    - Element generalization
      Elements are generalized by examining the @class attribute. When a generalization process detects that an element belongs to one of the modules that is being generalized, the element is renamed to a more general form.
    - Processor expectations when generalizing elements
      Generalization processors convert elements from one or more modules into their less specialized form. The list of modules can be supplied to a generalization processor, or it can be inferred based on knowledge of a target document-type shell.
    - Attribute generalization
      DITA provides a syntax to generalize attributes that have been specialized from the @props or @base attribute. Specialization-aware processors SHOULD process both the specialized and generalized forms of an attribute as equivalent in their values.
    - Generalization with cross-specialization dependencies
      Dependencies across specializations limit generalization targets to those that either preserve the dependency or eliminate them. Some generalization targets will not be valid and should be detected before generalization occurs.
  - Constraints
    Constraint modules define additional constraints for vocabulary modules in order to restrict content models or attribute lists for specific element types, remove certain extension elements from an integrated domain module, or replace base element types with domain-provided, extension element types.
- Coding practices for DITA grammar files
  This section collects all of the rules for creating modular DTD, RELAX NG, or XML Schema grammar files to represent DITA document types, specializations, and constraints.
- Technical content specializations
  This section contains information about the technical content specializations. It includes a summary of the document types and domains, as well as information about how the technical content specializations support authoring troubleshooting information.
- Learning and training specializations
  The section contains information about the learning and training specializations: Challenges faced by developers of instructional content; use cases; objectives of the specializations; information about the reusable learning-objects approach to learning and training content; summary of the topic types and domains; and more.
Language reference: All-inclusive edition
The language reference portion of the DITA specification contains a topic for each DITA element. The topic defines the element, its inheritance hierarchy, and provides examples of usage. This portion of the DITA specification also includes information about DITA attributes.
Conformance
Conformance to the DITA specification allows documents and document types that are used with different processors or different versions of a processor to produce the same or similar results with little or no reimplementation or modification.
Acknowledgments
(Non-normative) Many members of the OASIS DITA Technical Committee participated in the creation of this specification and are gratefully acknowledged.
Non-normative information
This section contains non-normative information, including topics about new features in DITA 1.3 and migrating from DITA 1.2 to DITA 1.3.
Content models for learning and training package
For each element in the learning and training package, this section presents the content model and a list of parent elements that can contain that element.

Attribute generalization

DITA provides a syntax to generalize attributes that have been specialized from the @props or @base attribute. Specialization-aware processors SHOULD process both the specialized and generalized forms of an attribute as equivalent in their values.

When a specialized attribute is generalized to an ancestor attribute, the value of the ancestor attribute consists of the name of the specialized attribute followed by its specialized value in parentheses. For example, if @jobrole is an attribute specialized from @person, which in turn is specialized from @props:

jobrole="programmer" can be generalized to person="jobrole(programmer)" or to props="jobrole(programmer)"
props="jobrole(programmer)" can be respecialized to person="jobrole(programmer)" or to jobrole="programmer"

In this example, processors performing generalization and respecialization can use the @domains attribute to determine the ancestry of the specialized @jobrole attribute, and therefore the validity of the specialized @person attribute as an intermediate target for generalization.

If more than one attribute is generalized, the value of each is separately represented in this way in the value of the ancestor attribute.

Generalized attributes are typically not expected to be authored or edited directly. They are used by processors to preserve the values of the specialized attributes during the time or in the circumstances in which the document is in a generalized form.

Note: The @audience, @platform, @product, and @otherprops attributes allow grouped values that reuse the generalized syntax described here; however, these attributes are not specialized or specializeable. For these attributes, it can be typical to author or edit the grouped values directly.

A single element MUST NOT contain both generalized and specialized values for the same attribute. For example, the following <p> element provides two values for the @jobrole attribute, one in a generalized syntax and the other in a specialized syntax:

<p person="jobrole(programmer)" jobrole="admin">
    <!-- ... -->
</p>

This is an error condition, since it means the document has been only partially generalized, or that the document has been generalized and then edited using a specialized document type.