AutoGen is a tool designed for generating program files that contain
repetitive text with varied substitutions. Its goal is to simplify the
maintenance of programs that contain large amounts of repetitious text.
This is especially valuable if there are several blocks of such text that
must be kept synchronized. 

One common example is the problem of maintaining the code required for
processing program options. Processing options requires a minimum of four
different constructs be kept in proper order in different places in your
program. You need at least: 

   1. The flag character in the flag string, 
   2. code to process the flag when it is encountered, 
   3. a global state variable or two, and 
   4. a line in the usage text. 

WWW: http://autogen.sourceforge.net/