`<no-topic-nesting>`

The <no-topic-nesting> element is a placeholder in the DITA architecture.

Usage information

The <no-topic-nesting> element is not intended for use in DITA source files.

The <no-topic-nesting> element is designed for use only when configuring a document-type shell using DTD syntax. It enables the DITA practitioner to disallow topic nesting for the topic type. This element is not required for document-type shells created using RELAX NG, which uses the native RNG <empty> element to accomplish the same thing.

Content model

EMPTY

Empty

Attributes

The following attribute is available on this element: @class.

@class (not for use by authors): This attribute is not for use by authors. If an editor displays @class attribute values, do not edit them. Specifies a default value that defines the specialization ancestry of the element. Its predefined values allow DITA tools to work correctly with specialized elements. In a generalized DITA document the @class attribute value in the generalized instance might differ from the default value for the @class attribute for the element as given in the DTD or schema. See The class attribute rules and syntax for more information. This attribute is specified on every element except for the <dita> container element. It is always specified with a default value, which varies for each element.

Example

This section is non-normative.

In the DTD document-type shells that are distributed by OASIS for the base topic, the %topic-info-types; entity is set to topic. This means that <topic> elements can nest other <topic> elements. The following code sample shows how the %topic-info-types; entity can be redefined using no-topic-nesting in order to disallow nested topics:

<!ENTITY % topic-info-types
              "no-topic-nesting"
>

Now, topics that use that document-type shell can no longer nest other topics. DTD grammar rules require that some element be specified in this entity, so <no-topic-nesting> is used as a placeholder.