;;; Copyright © 2022 Maxime Devos
;;;
;;; This library is free software: you can redistribute it and/or modify
;;; it under the terms of the GNU Lesser General Public License as
;;; published by the Free Software Foundation, either version 3 of the
;;; License, or (at your option) any later version.
;;;
;;; This library is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;;; Lesser General Public License for more details.
;;;
;;; You should have received a copy of the GNU Lesser General Public
;;; License along with this program.  If not, see
;;; <http://www.gnu.org/licenses/>.

(define-syntax set!-values
  (syntax-rules ()
    ((_ (var var* ...) exp)
     (call-with-values
       (lambda () exp)
       (lambda (value . rest)
         (set! var value)
         (set!-values (var* ...) (apply values rest)))))
    ((_ () exp)
     (call-with-values
       (lambda () exp)
       (lambda () (values)))))) ; nothing to do!

(define x)
(define y)
(define z)
(set!-values (x y z) (values 0 1 2))
(pk x y z)