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Re: case source code


From: Damien Mattei
Subject: Re: case source code
Date: Mon, 12 Sep 2022 10:30:40 +0200

just forget to add , if it is unclear it is 'case of scheme:
https://www.gnu.org/software/guile/docs/docs-1.8/guile-ref/if-cond-case.html#if-cond-case

On Mon, Sep 12, 2022 at 10:27 AM Damien Mattei <damien.mattei@gmail.com> wrote:
sorry if my question was unclear , i search the source code if it exist in scheme with macro (or not) but not in C for the 'case function (procedure or macro) , i want to modify the code to allow inner definitions the way i do it for example with 'do:

;; with a definition inside only the new version works:
;; (do ((i 1 (1+ i))
;;      (p 3 (* 3 p)))
;;     ((> i 4)
;;      p)
;;   (define x 7)
;;   (set! p (+ p i x)))
;; $3 = 1257

(define-syntax do

  (syntax-rules ()

    ((do ((var init step ...) ...)

         (test expr ...)

         command ...)

     (letrec

       ((loop

         (lambda (var ...)

           (if test

               ;;(begin
      (let ()

                 #f ; avoid empty begin

                 expr ...)

               ;;(begin
      (let ()

                 command

                 ...

                 (loop (do "step" var step ...)

                       ...))))))

       (loop init ...)))

    ((do "step" x)

     x)

    ((do "step" x y)

     y)))

regards,
Damien

On Mon, Sep 12, 2022 at 9:46 AM Zelphir Kaltstahl <zelphirkaltstahl@posteo.de> wrote:
Hello Damien,

On 9/12/22 09:42, Damien Mattei wrote:
> Hello,
> i can not find in the scheme community a definition of 'case in term of
> macro as for when, unless,while,do... does anyone have it?
> thanks,
> Damien

Can you give an example of what form you mean?

Regards,
Zelphir

--
repositories: https://notabug.org/ZelphirKaltstahl


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