[r6rs-discuss] Promises and Multiple Values

From: Alan Watson <alan>
Date: Mon, 23 Jul 2007 16:27:04 -0500

Eli,

Thanks for the pointer to SRFI-45. I like your simpler version, although
it does still contains a closure. For posterity, here is a cleaned-up
and tested version:

(define make-promise
   (lambda (x)
     (lambda ()
       (if (procedure? x)
           (let ((r (call-with-values x list)))
             (if (procedure? x)
                 (set! x r))))
       (apply values x))))

All of this is probably moot, though, as I suspect the R5RS
compatibility library is intended to be bug-compatible with the R5RS.

Regards,

Alan
Received on Mon Jul 23 2007 - 17:27:04 UTC