gistfile1.scm

 
(define-syntax while-less
  (syntax-rules (do)
    [(while-less e1 do e2)
       (if (< e1 e2)
           #t
           e2)]))  
;; this is obviously wrong, but I'm not sure how to eval e2 until (< e1 e2)
 
 
(define a 2)
(while-less 7 do (begin (set! a (+ a 1)) (print "x") a))
;; should print x x x x x and set a=7
(print a)
(while-less 7 do (begin (set! a (+ a 1)) (print "x") a))
;; should print x and set a=8
(print a)