* rec in kawa?
@ 2023-10-07 8:32 Damien Mattei
2023-10-07 8:39 ` Damien Mattei
0 siblings, 1 reply; 2+ messages in thread
From: Damien Mattei @ 2023-10-07 8:32 UTC (permalink / raw)
To: kawa mailing list
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?
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: rec in kawa?
2023-10-07 8:32 rec in kawa? Damien Mattei
@ 2023-10-07 8:39 ` Damien Mattei
0 siblings, 0 replies; 2+ messages in thread
From: Damien Mattei @ 2023-10-07 8:39 UTC (permalink / raw)
To: kawa mailing list
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?
^ permalink raw reply [flat|nested] 2+ messages in thread
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