Specialization of attributes

When creating a structural specialization, you can limit the contents of existing attributes on your new elements; you can also create new attributes through domain specialization based off of the props attribute (for conditional processing) or the base attribute (for other simple token attributes).

Domain attribute specialization allows DITA document type developers to incorporate new conditional processing attributes that can be used for filtering and flagging, or new attributes with no existing equivalent that can be managed and generalized in the same way as conditional processing attributes.

The new attributes need to be based off of either props or base:

Attributes specialized from props are identified as conditional processing attributes
Attributes specialized from base have no existing behavior associated with them
Values in specialized attributes should be preserved during generalization and respecialization
While generalized, the attribute values should still be understandable by both general and specialized behaviors, and be treated as equivalent to their specialized form. For example, conditional filtering should work the same way on specialized attributes and on generalized attributes.

Because there is a strong possibility that the existing conditional processing attributes (audience, platform, product, and otherprops) will be moved into a domain based off of props in the future, structural specializations are discouraged from limiting the values in those attributes.