anchor.diff:  (defun inventory ()
     (cons 'items- (objects-at 'body *objects* *object-locations*)))
   
  -(defun game-repl ()
  -  (let ((cmd (game-read)))
  -    (unless (eq (car cmd) 'quit)
  -      (game-print (game-eval cmd))
  -      (game-repl))))
  +(defparameter *allowed-commands* '(look walk pickup inventory))
  +
  +(defun game-eval (sexp)
  +  (if (member (car sexp) *allowed-commands*)
  +      (eval sexp)
  +      '(i do not know that command.)))
   
   (defun game-read ()
     (let ((cmd (read-from-string
  
positive.code:     (flet ((quote-it (x)
               (list 'quote x)))
        (cons (car cmd) (mapcar #'quote-it (cdr cmd))))))
  
  (defparameter *allowed-commands* '(look walk pickup inventory))
  
  (defun game-eval (sexp)
    (if (member (car sexp) *allowed-commands*)
        (eval sexp)
        '(i do not know that command.)))
  
  (defun tweak-text (lst caps lit)
    (when lst
  
negative.code:                  'string))
    (fresh-line))
  
  (defun game-repl ()
    (let ((cmd (game-read)))
      (unless (eq (car cmd) 'quit)
        (game-print (game-eval cmd))
        (game-repl))))
  
  