Derived expressions for Let, SICP exercise 4.6

ex46.scm

(define (let? exp)
  (tagged-list? exp 'let))

(define (let-clauses exp)
  (cdr exp))

(define (get-parameters clauses)
  (if (null? (car clauses))
      '()
      (cons (caaar clauses)
            (get-parameters (cons (cdar clauses) (cdr clauses))))))
;; Test

;;(get-parameters '(((v1 exp1) (v2 exp2)) 'body)) 

;Value 11: (v1 v2)

(define (get-exps clauses)
  (if (null? (car clauses))
      '()
      (cons (cadaar clauses)
            (get-exps (cons (cdar clauses) (cdr clauses))))))
(define (get-body clauses)
  (cdr clauses))
;; Test
;;(get-exps '(((v1 exp1) (v2 exp2)) 'body))

;Value 15: (exp1 exp2)

(define (let->combination cla)
     (cons (make-lambda (get-parameters cla) (get-body cla)) (get-exps cla)))