continuations

In this thread, you may post code that makes use of continuations, and I will attempt to produce code that does the same and looks reasonably similar, without using continuations.

>>56
All non deterministic programming can be expressed as deterministic operations on lazy lists that invoke continuations upon evaluation.

Anything that can be done with continuations, can be done with tail recursion in programs that don't use the native stack.

Translating....


(define (fact-normal n)
  (if (= n 0)
    1
    (* n (fact-normal (- n 1)))))

To.....................


(define (fact2 return n)
  (if (= n 0)
    (return 1)
    (fact2 (lambda (ret-val)
             (return (* n ret-val)))
           (- n 1))))