process_input - inspect (and possibly modify) user input

mixed process_input( string );

If process_input is present in the player object, then the MudOS driver
will send it a copy of each line the player types.  If a string is returned,
that string is used as instead of the user input for further processing.
If a non-zero, non-string is returned, no further processing is done.
If zero is returned, processing continues with the original input.
Matching against add_actions is then done.

Note: If NO_ADD_ACTION is defined, then there is no more processing to be
done after process_input.  In this case, the return value is ignored, and
the mudlib is responsible for interpreting the string as a command (or other
user input for non-command based uses).

See also:  add_action

 Tim Hollebeek  Beek@ZorkMUD, Lima Bean, IdeaExchange, and elsewhere
