<keydef>

A key definition provides a simple way to define a key without making the definition itself a part of rendered content.

Usage information

The <keydef> element is a convenience element. It is equivalent to a <topicref> element that defines a key while also setting @processing-role to resource-only.

Attributes defaulted on the <keydef> element ensure that key definitions do not appear in tables of contents, do not add extra links, and are not rendered as topics.

Specialization hierarchy

The <keydef> element is specialized from <topicref>. It is defined in the mapgroup-domain module.

Attributes

The following attributes are available on this element: common map attributes, link-relationship attributes, universal attributes, @impose-role, and @keyref.

For this element, the following considerations apply:
  • The @impose-role attribute has a fixed value of keeptarget.
  • The @keys attribute is required.
  • The @href attribute might be omitted when the key definition is used for variable text.
  • The @processing-role attribute has a default value of resource-only.

Example

The following code sample shows several different types of key definitions:

<map>
  <title>Possible keys for use in the DITA specification</title>
  <!-- Key definition #1-->
  <keydef keys="dita-tc" scope="external" format="html"
          href="https://www.oasis-open.org/committees/tc_home.php?wg_abbrev=dita">
    <topicmeta>
      <keytext>DITA Technical Committee</keytext>
    </topicmeta>
  </keydef>
  <!-- Key definition #2-->
  <keydef keys="addressing" href="dita-addressing.dita"/>
  <!-- Key definition #3-->
  <keydef keys="dita-version">
    <topicmeta>
      <keytext>2.0</keytext>
    </topicmeta>
  </keydef>
</map>
  1. The first <keydef> element defines a key that links to a web page. It contains link text; it also specifies the necessary @scope and @format attributes, so that authors do not need to include them when they reference this key.
  2. The second <keydef> element defines a key for a local DITA topic about addressing in DITA; that topic is available to resolve link text.
  3. The third <keydef> element defines a text-only key that specifies the current DITA version number.