;;;
;;; ps7.ss
;;; CS200 Problem Set 7
;;;
;;; Template for PS7 - put all the code you change in this file.
;;;

(require (lib "trace.ss"))
(load "listprocs.ss")
(load "meval.ss")

;;;
;;; Question 1:
;;;


;;;
;;; Question 2:
;;;

;;; You will need to change meval (from meval.ss).  Make your changes here so you don't need to 
;;; turn in all of meval.ss.

(define (meval expr env)
  (cond
   ((self-evaluating? expr) expr)
   ((quoted? expr)          (text-of-quotation expr))
   ((definition? expr)      (define-variable! 
			      (definition-variable expr)
			      (meval (definition-value expr) env) env))
   ((lambda? expr)          (make-procedure (lambda-parameters expr) (lambda-body expr) env))
   ((application? expr)     (mapply (meval (application-operator expr) env) 
				    (map (lambda (subexpr) (meval subexpr env))
					 (application-operands expr))))
   ((variable? expr)        (environment-lookup-name expr env))
   (else (error "Unrecognized expression: " expr))))


;;;
;;; Question 3:
;;;

;;;
;;; Question 4:
;;;


;;;
;;; Question 5:
;;;


;;;
;;; Question 6:
;;;


;;;
;;; Question 7:
;;;


;;;
;;; Question 8:
;;;


;;;
;;; Question 9:
;;;

;;; If you make changes in pegboard.ss and print out the whole file, make sure
;;; to CLEARLY MARK the changes you made.