<attributedef>

Example

In this example, enumerations are specified for the @platform and @otherprops attributes. Note that the enumeration identifies a category of values; the values within the category are valid, while the category itself is not a valid value. For example, in the code sample here, the @platform attribute is associated with the enumeration for the category "os"; all values within the "os" category are thus valid on the @platform attribute, while the value "os" itself is not.

<subjectScheme>
  <!-- Pull in a scheme that defines unix OS values -->
  <schemeref href="unixOS.ditamap"/>
  <!-- Define new OS values that are merged with those in the unixOS scheme -->
  <subjectdef keys="os">
    <subjectdef keys="linux"/>
    <subjectdef keys="mswin"/>
    <subjectdef keys="zos"/>
  </subjectdef>
  <!-- Define application values -->
  <subjectdef keys="app" navtitle="Applications">
    <subjectdef keys="apacheserv" href="subject/apache.dita"/>
    <subjectdef keys="mysql"      href="subject/sql.dita"/>
  </subjectdef>

  <!-- Define an enumeration of the platform attribute, equal to
       each value in the OS subject. This makes the following values
       valid for the platform attribute: linux, mswin, zos -->
  <enumerationdef>
    <attributedef name="platform"/>
    <subjectdef keyref="os"/>
  </enumerationdef>
  <!-- Define an enumeration of the otherprops attribute, equal to
       each value in the application subjects.
       This makes the following values valid for the otherprops attribute:
       apacheserv, mysql -->
  <enumerationdef>
    <attributedef name="otherprops"/>
    <subjectdef keyref="app"/>
  </enumerationdef>
</subjectScheme>