Preferred Index Terms

[Eliot Kimber <ekimber@contrext.com>]

An indexing requirement that DITA does not currently satisfy out of the box is identify an instance of an index term as being the "preferred" instance. Preferred instances are usually rendered by highlighting the page number (or other locator) for that entry.

DocBook provides for this with the @significance attribute of the <indexterm> element: 

https://tdg.docbook.org/tdg/5.2/indexterm.singular.html

Where the @significance attribute has the value "normal" or "preferred":

<indexterm significance="preferred"><primary>apple</primary></indexterm>

It seems reasonable to add this mechanism to DITA.

I can see two ways it could be done:

1. Add an attribute like @significance to <indexterm>, basically exactly what DocBook does.
2. Specialize <indexterm> to <indexterm-preferred>.

Option 2 could of course be done by anyone who wants to define the specialization, and maybe that's the answer: if you have this requirement, implement the specialization and the processing for it.

But I wanted to at least record the requirement for discussion.

Cheers,

E.
--
Eliot Kimber
http://contrext.com