;;; Interpreter for lambda calculus expressions
;;; It contains the NON-CPS version of primitive
;;; procedure applications. Translate it to CPS

(load "chez-init.ss")
(load "env.ss")
(load "cont.ss")
(load "parser.ss")
(define (rl) (load "interpreter.ss"))

(define eval-one-exp
  (lambda (exp)
    (top-level-eval (parse-expression exp))))


(define rep
  (lambda ()
    (display ">> ")
    (let ([input (read)])
      (if (equal? input '(exit))
	  (printf "Bye...~%")
	  (let* ([parse-tree (parse-expression input)]
		 [response (top-level-eval parse-tree)])
	    (pretty-print response)
	    (rep))))))


(define top-level-eval
  (lambda (form)
    (eval-expression form (halt-cont) (extend-env '(a b) '(3 4) (empty-env)))))


(define eval-expression
  (lambda (exp cont env)
    (cases expression exp
	   [var-exp (id) (apply-cont cont (apply-env env id))]
	   [lit-exp (val) (apply-cont cont val)]
	   [if-exp (test-exp true-exp false-exp)
		   (eval-expression test-exp
				    (if-cont true-exp false-exp cont env)
				    env)]
	   [prim-app (primitive expression-list)
		     (eval-expressions expression-list (apply-prim-cont primitive cont) env)])))


;(define eval-expressions
;  (lambda (exps env)
;    (if (null? exps)
;	'()
;	(cons (eval-expression (car exps) env)
;	      (eval-expressions (cdr exps) env)))))

;(define eval-expressions
;  (lambda (exps cont env)
;    (if (null? exps)
;	'()
;	(eval-expression (car exps)
;			 (lambda (hole1)
;			   (eval-expressions (cdr exps)
;					     (lambda (hole2)
;					       (cons hole1 hole2))
;					     env))
;			 env))))

(define eval-expressions
  (lambda (exps cont env)
    (if (null? exps)
	(apply-cont cont '())
	(eval-expression (car exps) (eval-cont (cdr exps) cont env) env))))



(define apply-primitive-procedure
  (lambda (name args)
    (case name
      [(+) (apply + args)])))