17.4.3 @value Example

You can use the @value command to minimize the number of places you need to change when you record an update to a manual. See section GNU Sample Texts, for the full text of an example of using this to work with Automake distributions.

This example is adapted from (make)Top section `Overview' in The GNU Make Manual.

1. Set the flags:

   @set EDITION 0.35 Beta @set VERSION 3.63 Beta @set UPDATED 14 August 1992 @set UPDATE-MONTH August 1992

2. Write text for the @copying section (see section @copying: Declare Copying Permissions):

   @copying This is Edition @value{EDITION}, last updated @value{UPDATED}, of @cite{The GNU Make Manual}, for @code{make}, version @value{VERSION}. Copyright … Permission is granted … @end copying

3. Write text for the title page, for people reading the printed manual:

   @titlepage @title GNU Make @subtitle A Program for Directing Recompilation @subtitle Edition @value{EDITION}, … @subtitle @value{UPDATE-MONTH} @page @insertcopying … @end titlepage

   (On a printed cover, a date listing the month and the year looks less fussy than a date listing the day as well as the month and year.)

4. Write text for the Top node, for people reading the Info file:

   @ifnottex @node Top @top Make @insertcopying … @end ifnottex

   After you format the manual, the @value constructs have been expanded, so the output contains text like this:

   This is Edition 0.35 Beta, last updated 14 August 1992, of `The GNU Make Manual', for `make', Version 3.63 Beta.

When you update the manual, you change only the values of the flags; you do not need to edit the three sections.