prog/gnu/guile/c-for.scm

;; I double dog dare you to say this program name outloud.
;;
;; C's version of 4
;;
;; for (i = 0; i < 5; i++) {
;; printf ("Number is %d\n", i);
;; }
;;
;; Let's add a scheme for loop!
;; (for (i 0) (< i 5) (+ i 2)
;;   (format #t "Number is ~a" i))


;; (for (i 0) (< i 5) (+ i 1)
;;     (format #t "~a\n" i))
(define-syntax-rule (for (i j-0) (comparison m k-5) (operator n l-1)
                         body ...)
  (begin
    (define j-var j-0)
    (define k-var k-5)
    (define l-var l-1)
    (define (generator i)
      (define (loop k-var l-var)
        (cond ((comparison i k-5)
               (set! i (operator i l-1))
               body ...
               (loop k-5 l-1))
              (else '())))
      loop)

    (define run-for (generator j-var))
    (run-for k-5 l-1)))

(for (i 0) (< i 5) (+ i 1)
     (display "i is: ")
     (format #t "~a\n" i))

;; Part 2: can you write this macro without using closures?