; Define a Lisp structure, which is much like an object, called
; silly-vacuum agent.
; Programmed by Dave Musicant
(defstruct (silly-vacuum-agent 

   ; Inherit all properties from a pre-existing structure called 'agent'
   (:include agent

   ; Override a variable named 'program' from the 'agent'
   ; structure so that it will point to the new function we'll create
     (program 

     ; Define an 'instance variable' called non-moves,
     ; that will persist over multiple function calls
       (let ((num-moves 0))

         ; Define a function that takes a list of percepts as a parameter
         #'(lambda (percept)

           ; --- DON'T CHANGE ANY OF THE ABOVE CODE, WITH THE EXCEPTION
           ; --- OF THE 'LET' STATEMENT AND THE NAME AT THE TOP.
           ; --- CHANGE CODE BELOW AS YOU PLEASE.

           ; Pause for keyboard input so the program doesn't scoll like mad.
           (read-line)

           ; Separate the percepts for easier processing.
           (setf bump (first percept))
           (setf dirt (second percept))
           (setf home (third percept))

           ; Proceed around the board, stopping when reach home, assuming
           ; you actually went somewhere.
           (if (and home (> num-moves 2)) 'shut-off
             (progn
               (setf num-moves (+ 1 num-moves))
               (cond
                (dirt 'suck)
                (bump '(turn right))
                (t 'forward))))))))))