Re: reserved-keyword in macro

[Maxime Devos]

Damien Mattei schreef op vr 04-02-2022 om 17:24 [+0100]:
> even with $nfx$ it does not seem to be possible without set!-values:
> https://docs.racket-lang.org/reference/set_.html#%28form._%28%28lib._racket%2Fprivate%2Fmore-scheme..rkt%29._set%21-values%29%29
> 
> does someone know how to implement set!-values in Scheme for Guile?

This is not Guile-specific, it works in any Scheme with syntax-rules,
by using a form of recursion, call-with-values, set!, lambda and
values, see attachement (LGPL3.0+ licensed).

Also, Racket is free software, so you could look at the source code of
Racket, maybe Racket's implementation can be ported to Guile Scheme and
maybe it's already valid Guile Scheme.

> On Fri, Feb 4, 2022 at 9:21 AM Damien Mattei <damien.mat...@gmail.com>
> wrote:
> [ a huge block of text ]

This block of text does not appear to have anything to do with your
question, what is it included for?

Greetings,
Maxime.

;;; 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)

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