Guide to LaTeX (4th Edition) (Tools and Techniques

470 Appendix D. L AT E X Programming
number. In the second case, the code lines are not numbered, unless the
declaration \CodelineNumbered is also issued.
Since not all commands in the coding really need to be indexed, especially
those that are part of standard L AT E X and T E X, the command
\DoNotIndex{list of command names}
is given, often repeatedly, near the beginning, to exempt the listed commands
from being indexed.
The automatic indexing of all the commands in the code slows down
the processing considerably. Once the index.idx file has been produced,
future runs do not need to repeat this effort (unless there have been
changes to the code). The command
\DisableCrossrefs
will suppress this indexing, but it may be countermanded by an earlier
\EnableCrossrefs which neutralizes the disabling command.
The text of the index is generated from the .idx data file by the
MakeIndex program (Section 9.4.3), which must be run with the special
indexing style gind.ist as
makeindex -s gind.ist filename
The indexing style file gind.ist can be extracted from doc.dtx.
To print the index, the command
\PrintIndex
is placed where it should appear. Often this is part of the final text in
\StopEventually. An up-to-date index can only appear after MakeIndex
has been run between two L AT E X processings.
A record of changes to the software can be made by inserting
\changes{version}{date}{text}
throughout the documentation, in both the description and coding parts.
To form the change history list, the command
\RecordChanges
must be placed in the preamble. This enables the change entries to be
placed in a glossary file, which is then processed by MakeIndex as
makeindex -s gglo.ist -o filename.gls filename.glo
(The indexing style file gglo.ist is also extracted from doc.dtx.) The
change history is then printed in the documentation where
\PrintChanges
is located, again often as part of final text. The texts of the \changes
commands are ordered, first by version number, then by the name of the
macro or environment in which they appear.