How to recursively reverse a list using only basic operations?

Question

I was wondering how to reverse a list using only basic operations such as cons, first, rest, empty?, etc.

No helper functions or accumulators allowed, and the funct

Answer 1

(define (reverse x)
  (let loop ((x x) (y '()))
    (if (null? x)
        y
        (let ((temp (cdr x)))
          (set-cdr! x y)
          (loop temp x))))))

Really one of the few ways to do it efficiently. But still sort of a helper procedure.

Other way, but not tail-recursive, and if the append doesn't use a set-cdr! it's really unusable for large lists.

(define (reverse L)
  (if (null? l)
      '()
       (append (reverse (cdr L)) (list (car L)))))