anchor.diff:        (print lst out))))
   
   (defun save-bodies (filename)
  +  "Calls save-list and body-to-list"
     (save-list (bodies-to-list *bodies*) filename))
   
   (defun read-list (filename)
  +  "Reads from a file with the name given"
     (with-open-file (in filename)
       (with-standard-io-syntax
         (read in))))
   
   (defun read-bodies (filename)
  +  "Reads from a file and converts the lists in the file
  +   into instances of the body class"
     (loop for bod in (read-list filename)
          collecting (make-instance 
   		   'body
  
positive.code: ;; I/O functions
  
  (defun body-to-list (body)
    (list (x (pos body))
  	(y (pos body))
  	(x (vel body))
  
negative.code: 	(id body)))
  
  (defun bodies-to-list (bodies)
    "Calls body-to-list on a list of bodies"
    (mapcar #'body-to-list bodies))
  
  (defun save-list (lst filename)
    "Saves the list given to a file with the name given"
    (with-open-file (out filename
  		       :direction :output
  		       :if-exists :supersede)
  