anchor.diff:  (defun make-procedure (exp env)
     (let ((parameters (lambda-parameters exp))
   	(body (lambda-body exp)))
  -    ;; (format t "lambda: ~a~%" exp)
  -    ;; (format t "lambda parameters: ~a~%" parameters)
  -    ;; (format t "lambda body: ~a~%" body)
  +    (format t "lambda: ~a~%" exp)
  +    (format t "lambda parameters: ~a~%" parameters)
  +    (format t "lambda body: ~a~%" body)
      `(procedure ,parameters ,body ,env)))
   
   (defun procedure-parameters (procedure)
  
positive.code:   (if (symbolp (cadr exp))
        (caddr exp)
        (make-lambda (cdadr exp)
  		   (caddr exp))))
  
  (defun make-lambda (parameters body)
    `(lambda (,parameters . ,body)))
  
  (defun lambda-parameters (exp)
    (cadr exp))
  
  (defun lambda-body (exp)
    (cddr exp))
  
  (defun assignment-p (exp)
    (tagged-list-p exp 'set!))
  
negative.code:     (iter (frame-vars frame) (frame-vals frame))))
  
  (defun t-eval (exp env)
    (format t "t-eval: ~a~%" exp)
    (cond
      ((self-evaluating-p exp) exp)
      ((variable-p exp) (env-get env exp))
  