texinfo: New Indices

Indices

Combining Indices

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13.5 Defining New Indices
=========================

In addition to the predefined indices (Note: Predefined Indices), you
may use the '@defindex' and '@defcodeindex' commands to define new
indices.  These commands create new indexing @-commands with which you
mark index entries.  The '@defindex' command is used like this:

     @defindex NAME

  New index names are usually two-letter words, such as 'au'.  For
example:

     @defindex au

  This defines a new index, called the 'au' index.  At the same time, it
creates a new indexing command, '@auindex', that you can use to make
index entries.  Use this new indexing command just as you would use a
predefined indexing command.

  For example, here is a section heading followed by a concept index
entry and two 'au' index entries.

     @section Cognitive Semantics
     @cindex kinesthetic image schemas
     @auindex Johnson, Mark
     @auindex Lakoff, George

(Evidently, 'au' serves here as an abbreviation for "author".)

  Texinfo constructs the new indexing command by concatenating the name
of the index with 'index'; thus, defining an 'xy' index leads to the
automatic creation of an '@xyindex' command.

  Use the '@printindex' command to print the index, as you do with the
predefined indices.  For example:

     @node Author Index
     @unnumbered Author Index

     @printindex au

  The '@defcodeindex' is like the '@defindex' command, except that, in
the printed output, it prints entries in an '@code' font by default
instead of a roman font.

  You should define new indices before the end-of-header line of a
Texinfo file, and (of course) before any '@synindex' or '@syncodeindex'
commands (Note: Texinfo File Header).

  As mentioned earlier (Note: Predefined Indices), we recommend having
a single index in the final document whenever possible, however many
source indices you use, since then readers have only one place to look.

  When creating an index, TeX creates a file whose extension is the name
of the index (Note: Names of index files).  Therefore you should avoid
using index names that collide with extensions used for other purposes,
such as '.aux' or '.xml'.  'makeinfo' already reports an error if a new
index conflicts well-known extension name.