Closure Conversion

gistfile1.scm

(define (f)
  (let ((x 0))
    (let ((up (lambda () (set! x (+ x 1)) x))
          (dn (lambda () (set! x (- x 1)) x)))
      (cons up dn))))

(define g (f))

((car g))  ;=> 1
((car g))  ;=> 2
((car g))  ;=> 3
((cdr g))  ;=> 2
((cdr g))  ;=> 1
((car g))  ;=> 2