From: Damien Mattei <damien.mattei@gmail.com>
To: kawa mailing list <kawa@sourceware.org>
Subject: Re: rec in kawa?
Date: Sat, 7 Oct 2023 10:39:15 +0200 [thread overview]
Message-ID: <CADEOadffmTaFrOsLnKRvjRiOdxS1NtBS-Sr0QUuDsLuucWLe9w@mail.gmail.com> (raw)
In-Reply-To: <CADEOaddBoXOLX0hDA6ZOA+fysn5uM1ytgUkPf_HcL=JudW13uw@mail.gmail.com>
ok ,from SRFI 31:
(define-syntax rec
(syntax-rules ()
((rec (NAME . VARIABLES) . BODY)
(letrec ( (NAME (lambda VARIABLES . BODY)) ) NAME))
((rec NAME EXPRESSION)
(letrec ( (NAME EXPRESSION) ) NAME))))
perheaps a good idea to make it default include in kawa....
#|kawa:1|# (load "Scheme+.scm")
#|kawa:2|# (def (bar n) (cond ((= n 0) 'end0) ((= n 7) (return-rec
'end7)) (else (cons n (bar (- n 1))))))
#|kawa:3|# (bar 5)
(5 4 3 2 1 . end0)
#|kawa:4|# (bar 10)
end7
#|kawa:5|# (def (foo n) (cond ((= n 0) 'end0) ((= n 7) (return 'end7))
(else (cons n (foo {n - 1})))))
/dev/tty:5:87: invalid character #\}
#|kawa:6|# (def (foo n) (cond ((= n 0) 'end0) ((= n 7) (return 'end7))
(else (cons n (foo (- n 1))))))
#|kawa:7|# (foo 5)
(5 4 3 2 1 . end0)
#|kawa:8|# (foo 10)
(10 9 8 . end7)
On Sat, Oct 7, 2023 at 10:32 AM Damien Mattei <damien.mattei@gmail.com> wrote:
>
> i have this definition but i miss rec in kawa:
>
> ;; scheme@(guile-user)> (def (foo) (when #t (return "hello") "bye"))
> ;; scheme@(guile-user)> (foo)
> ;; "hello"
>
> ;; (def x)
>
>
>
> ;; (def (foo n)
> ;; (cond ((= n 0) 'end0)
> ;; ((= n 7) (return 'end7))
> ;; (else (cons n (foo {n - 1})))))
>
>
> ;; scheme@(guile-user)> (foo 5)
> ;; (5 4 3 2 1 . end0)
> ;; scheme@(guile-user)> (foo 10)
> ;; (10 9 8 . end7)
>
> ;; (def (bar n)
> ;; (cond ((= n 0) 'end0)
> ;; ((= n 7) (return-rec 'end7))
> ;; (else (cons n (bar {n - 1})))))
>
> ;; scheme@(guile-user)> (bar 5)
> ;; $4 = (5 4 3 2 1 . end0)
> ;; scheme@(guile-user)> (bar 10)
> ;; $5 = end7
> (define-syntax def
>
> (lambda (stx)
>
> (syntax-case stx ()
>
> ;; multiple definitions without values assigned
> ;; (def (x y z))
> ((_ (var1 ...)) #`(begin (define var1 '()) ...))
>
> ;; (def (foo) (when #t (return "hello") "bye"))
> ;; ((_ (<name> <arg> ...) <body> <body>* ...)
> ;; (let ((ret-id (datum->syntax stx 'return)))
> ;; #`(define (<name> <arg> ...)
> ;; (call/cc (lambda (#,ret-id) <body> <body>* ...)))))
>
>
> ((_ (<name> <arg> ...) <body> <body>* ...)
>
> (let ((ret-id (datum->syntax stx 'return))
> (ret-rec-id (datum->syntax stx 'return-rec)))
>
> #`(define (<name> <arg> ...)
>
> (call/cc (lambda (#,ret-rec-id)
>
> (apply (rec <name> (lambda (<arg> ...)
> (call/cc (lambda (#,ret-id) <body> <body>*
> ...)))) (list <arg> ...)))))))
>
>
>
>
> ;; single definition without a value assigned
> ;; (def x)
> ((_ var) #`(define var '()))
>
> ;; (def x 7)
> ((_ var expr) #`(define var expr))
>
> ((_ err ...) #`(syntax-error "Bad def form"))
>
> )))
>
>
> any idea of replacement for it?
prev parent reply other threads:[~2023-10-07 8:39 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-07 8:32 Damien Mattei
2023-10-07 8:39 ` Damien Mattei [this message]
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