#lang racket/base

(require racket/promise)

(define (repeatedly maximum err proc)
   (let loop ((tries 0))
     (let/ec
      okay
      (let/ec retry (call-with-values (λ () (proc retry)) okay))
      (if (< tries maximum)
        (loop (+ tries 1))
        (error (if (promise? err) (force err) err))))))

(define (test)
   (list
    (with-handlers
     ((exn:fail? (λ (e) "yay we failed\n")))
     (repeatedly 10 "fail" (λ (retry) (display "beep\n") (retry))))
    (repeatedly 10 "no problem" (λ (retry) "...BOOP\n"))))

(provide repeatedly)