Expending expression in Racket

expanding-expression.rkt

#lang racket
(define expr
  '(+ (- 5 (* 4 3)) (* 7 (* 2 8))))

(struct exp-and-holder (exp holder) #:transparent)

(define (main-converter exp)
  (let*
      ((var-holder '())
       (exp-holder (exp-and-holder exp var-holder)))
    (converter exp-holder)
  )
)
(define (append-line x y)
  (if (eq? x '())
      `(,y)
      (append x `(,y))))



(define (converter exp-holder)
  (begin
    (define exp (exp-and-holder-exp exp-holder))
    (define holder (exp-and-holder-holder exp-holder))
    (define lhs (cadr exp))
    (define rhs (caddr exp))
    (define return-holder holder)
    (define return-exp exp)


    (if (list? lhs)
        (let* (
          (lhs-counted (converter (exp-and-holder lhs holder)))
          (new-holder (exp-and-holder-holder lhs-counted))
          (lhs-tmp-var (gensym))
          (append-holder-item `(def ,lhs-tmp-var ,(exp-and-holder-exp lhs-counted))))
        (set! return-holder (append-line new-holder append-holder-item))
        (display return-holder)
        (set! return-exp `(,(car exp) ,lhs-tmp-var ,(list-ref exp 2)))
          )
    
        ; if lhs is a constant
        (let*
        ((lhs-tmp-var (gensym))
        (append-holder-item `(def ,lhs-tmp-var ,lhs)))
        (set! return-holder (append-line return-holder append-holder-item))
        (set! return-exp `(,(car exp) ,lhs-tmp-var ,(list-ref exp 2)))))
        

    (if (list? rhs)
        (let* (
          (rhs-counted (converter (exp-and-holder rhs return-holder)))
          (new-holder (exp-and-holder-holder rhs-counted))
          (rhs-tmp-var (gensym))
          (append-holder-item `(def ,rhs-tmp-var ,(exp-and-holder-exp rhs-counted))))
        (set! return-holder (append-line new-holder append-holder-item))
        (display new-holder)(newline)
          
        (set! return-exp `(,(car return-exp) ,(list-ref return-exp 1) ,rhs-tmp-var))
          )
    

        ; if rhs is a constant
        (let*
        ((rhs-tmp-var (gensym))
        (append-holder-item `(def ,rhs-tmp-var ,rhs)))
        (set! return-holder (append-line return-holder append-holder-item))
        (set! return-exp `(,(car return-exp) ,(list-ref return-exp 1) ,rhs-tmp-var)))
        

        
        
  )

  (exp-and-holder return-exp return-holder)
))

;(exp-and-holder
; '(+ g91751 g91756)
; '((def g91747 5) (def g91748 4) (def g91749 3) (def g91750 (* g91748 g91749))
; (def g91751 (- g91747 g91750)) (def g91752 7) (def g91753 2) (def g91754 8) (def g91755 (* g91753 g91754)) (def g91756 (* g91752 g91755))))
(main-converter expr)