let vs let*

gistfile1.rkt

;; scheme code:
(define (partial-tree elts n)
  (if (= n 0)
      (cons '() elts)
      (let ((left-size (quotient (- n 1) 2)))
        (let ((left-result (partial-tree elts left-size)))
          (let ((left-tree (car left-result))
                (non-left-elts (cdr left-result))
                (right-size (- n (+ left-size 1))))
            (let ((this-entry (car non-left-elts))
                  (right-result (partial-tree (cdr non-left-elts)
                                              right-size)))
              (let ((right-tree (car right-result))
                    (remaining-elts (cdr right-result)))
                (cons (make-tree this-entry left-tree right-tree)
                      remaining-elts))))))))
;; racket code:
(define (my-partial-tree elts n)
  (if (= n 0)
      (cons '() elts)
      (let* ([left-size (quotient (- n 1) 2)]
             [left-result (partial-tree elts left-size)]
             [left-tree (car left-result)]
             [non-left-elts (cdr left-result)]
             [right-size (- n (+ left-size 1))]
             [this-entry (car non-left-elts)]
             [right-result (partial-tree (cdr non-left-elts) right-size)]
             [right-tree (car right-result)]
             [remaining-elts (cdr right-result)])
        (cons (make-tree this-entry left-tree right-tree)
              remaining-elts))))