SETTIMER expression [ , expression ]

   Synopsis:
      Adds a dependent timer

   Notes:
      A convenient way to create a timer that launches another Axbasic script
         (or notifies this script's parent task) whenever it fires.
         
      The first expression is the stimulus (an interval, in seconds).
      (Axmud automatically assigns its own name to dependent triggers.)

      If the second expression is specified, it should be the name of an Axbasic
         script to run immediately (without a parent task) when the timer
         fires.
      If the second expression is omitted, this script's parent task receives a
         notification when the timer fires. Axbasic provides several intrinsic
         (built-in) functions for getting information about these notifiacations
         (see the help for NEXTIFACE for more information).
      Also see the help for WAITTIMER.

   Requires:
      If the script is not being run as a task, a SETTIMER statement without a
         second expression (specifying another script to run) is ignored (and no
         error message is generated). Execution continues with the next
         statement.
         
   Compatibility:
      Since Axbasic v1.4
      
   Examples:
      SETTIMER 180
      SETTIMER 180, "drink_potion"
