Configuration, specialization, and constraints
The extension facilities of DITA allow existing vocabulary and constraint modules
to be
combined to create specific DITA document types. Additionally, vocabulary modules
can be
extended to create more-specialized markup to meet new requirements not satisfied
by existing
markup.
In this section:
- Overview of DITA extension facilitiesDITA provides three extension facilities: configuration of the vocabulary modules used by DITA document types, constraint of base content models and attribute lists, and creation of new element and attribute types (specialization).
- Configuration (Document type shells)
- SpecializationThe specialization feature of DITA allows for the creation of new element types and attributes that are explicitly and formally derived from existing types. The resulting specialization allows for the blind interchange of all conforming DITA content and 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.
- ConstraintsConstraint modules define additional constraints for corresponding vocabulary modules in order to restrict content models or attribute lists for specific element types, remove extension elements from an integrated domain module, or replace base element types with domain-provided extension element types. Constraint modules do not and cannot change element semantics, only the details of how element types can be used in the context of a specific concrete document type. Because constraints can make optional elements required, documents that use the same vocabulary modules may still have incompatible constraints. Thus the use of constraints can affect the ability for content from one topic or map to be used directly in another topic or map.
Parent topic: Architectural Specification: Base