Re: reserved-keyword in macro

[Damien Mattei]

really,nothing have an idea? seems $bracket-apply$ is bind to the variable
var of the third case in the macro instead of ignored in the first case...
but why? (it the same thing if i change the patterns order)

On Wed, Feb 2, 2022 at 2:02 PM Damien Mattei <damien.mattei@gmail.com>
wrote:

> sorry i miss copy to mailing list...
>
> ---------- Forwarded message ---------
> From: Damien Mattei <damien.mattei@gmail.com>
> Date: Wed, Feb 2, 2022 at 12:09 PM
> Subject: Re: reserved-keyword in macro
> To: Maxime Devos <maximedevos@telenet.be>
>
>
> thanks maxim ,it works so my problem come from elsewhere
>
> scheme@(guile-user)> (define-syntax macro
>   (syntax-rules (reserved-keyword)
>     ((_ reserved-keyword arg) 'first)
> ... ((_ arg1 arg2) 'second)))
> scheme@(guile-user)> (macro 4 5)
> second
> scheme@(guile-user)> (macro reserved-keyword 5)
> first
>
> this was a simplified example my real case is this:
> (define-syntax <-
>
>   (syntax-rules ($bracket-apply$)
>
>     ;;  special form like : (<- ($bracket-apply$ T 3) ($bracket-apply$ T
> 4))
>
>     ;; one dimension array, example: {a[4] <- 7}
>     ;; $bracket-apply$ of SRFI 105
>     ((_ ($bracket-apply$ container index) expr)
>      (let ((value expr)) ;; to avoid compute it twice
>
>        ;; (if (equal? (quote $bracket-apply$) (quote funct-or-macro)) ;;
> test funct-or-macro equal $bracket-apply$
>
>        ;; normal case
>        ;; {T[2] <- 4}
>        ;; {T[3] <- T[2]}
>        ;;(begin
>        ;;(display "<- : vector or array set! or hash-table set!") (newline)
>        (cond ((vector? container) (vector-set! container index value))
>     ((hash-table? container) (hash-table-set! container index value))
>     (else (array-set! container index value)));)
>
>        ;; rare case  (to prevent any error)
>        ;; (let ((var (funct-or-macro container index))) ;; MUST be in a
> variable , otherwise:
>        ;; While compiling expression:
>        ;;  Syntax error:
>        ;;  unknown location: quote: bad syntax in form quote
>        ;; <- : variable set! after creation
>        ;;  (set! var value)))
>
>        value))
>
>
>     ;; multi dimensions array :  {a[2 4] <- 7}
>     ;; $bracket-apply$ of SRFI 105
>     ((_ ($bracket-apply$ array index1 index2 ...) expr)
>      (let ((value expr)) ;; to avoid compute it twice
>
>        ;; (if (equal? (quote $bracket-apply$) (quote funct-or-macro)) ;;
> test funct-or-macro equal $bracket-apply$
>        ;; normal case
>        ;;(begin
>        ;;(display "<- : multidimensional vector or array set!") (newline)
>        (if (vector? array)
>   (array-n-dim-set! array value index1 index2 ...)
>   (array-set! array index1 index2 ... value));)
>
> ;; rare case (to prevent any error)
> ;; (let ((var (funct-or-macro array index ...))) ;; MUST be in a variable
> ;;   (display "<- : variable set! after creation (multidimensional)")
> (newline)
> ;;   (set! var value)))
> value))
>
>      ;; not sure this case will be usefull
>     ;;  (define (foo) (values 1 2 3))
>     ;; (call-with-values foo list)
>     ;;'(1 2 3)
>     ;;  (define (foo) (display "inside foo") (newline) (values 1 2 3))
> ;; > (declare x y z)
> ;; > (<- (x y z) (foo))
>     ;; ((_ (funct-or-macro arg ...) expr)
>     ;;  (let ((var (funct-or-macro arg ...))
>     ;;   (value expr)) ;; to avoid compute it twice
>     ;;    (set! var value)
>     ;;    var))
>
>     ((_ (var ...) expr)
>      (begin
>      (display expr) (newline)
>      (let ((expr-list (call-with-values (lambda () expr) list)))
>
>        (assign-var (var ...) expr-list)
>        expr-list)))
>
>
>     ;;(<- x 5)
>     ((_ var expr)
>
>      (begin
>        ;;(display "<- : variable set!") (newline)
>        (set! var expr)
>        var))
>
>
>     ;; (declare x y z t)
>     ;; {x <- y <- z <- t <- 7}
>     ;; 7
>     ;; (list x y z t)
>     ;; (7 7 7 7)
>
>     ;; (declare I)
>     ;; {I <- (make-array 0 4 4)}
>     ;; #2((0 0 0 0)
>     ;;    (0 0 0 0)
>     ;;    (0 0 0 0)
>     ;;    (0 0 0 0))
>     ;;
>     ;; {I[0 0] <- I[1 1] <- I[2 2] <- I[3 3] <- 1}
>     ;; 1
>     ;;
>     ;; I
>     ;; #2((1 0 0 0)
>     ;;    (0 1 0 0)
>     ;;    (0 0 1 0)
>     ;;    (0 0 0 1))
>
>     ((_ var var1 var2 ...) ;; there is an expression in the last part of
> ellipsis!
>      (<- var (<- var1 var2 ...)))
>
>     ))
>
>
> ;; > (declare x y z)
> ;; > (assign-var (x y z) (1 2 3))
> ;; > x
> ;; 1
> ;; > y
> ;; 2
> ;; > z
> ;; 3
> (define-syntax assign-var
>   (syntax-rules ()
>
>     ((_ (var ...) (exp ...)) (begin (set! var exp) ...))))
>
> i'm cross developping in Guile and Racket and i'm sure Guile will do as
> Racket and here is the result:
>
> Bienvenue dans DrRacket, version 7.7 [3m].
> Langage: reader "../SRFI/SRFI-105.rkt", avec débogage; limite mémoire :
> 128 MB.
> > (declare x y z)
> > (define (foo) (display "inside foo") (newline) (values 1 2 3))
> > (<- (x y z) (foo))
> inside foo
> . .
> ../../../../../../../../usr/share/racket/collects/racket/private/kw.rkt:1201:25:
> result arity mismatch;
>  expected number of values not received
>   expected: 1
>   received: 3
>   values...:
> > (define T (make-vector 5))
> > {T[2] <- 1}
> 1
> . ../required-files/assignment.rkt:140:7: assign-var: bad syntax in:
> (assign-var ($bracket-apply$ T 2) expr-list)
> > (<- T[2] 1)
> . ../required-files/assignment.rkt:140:7: assign-var: bad syntax in:
> (assign-var (2) expr-list)
> > (<- ($bracket-apply$ T 2) 1)
> 1
> . ../required-files/assignment.rkt:140:7: assign-var: bad syntax in:
> (assign-var ($bracket-apply$ T 2) expr-list)
> >
>
> the problem is that anyway i do it when using reserved keyword in
> define-syntax the macro use the third case:
> (_ (var ...) expr)
> even when i have :
>
> (syntax-rules ($bracket-apply$)
>
>     ;;  special form like : (<- ($bracket-apply$ T 3) ($bracket-apply$ T
> 4))
>
>     ;; one dimension array, example: {a[4] <- 7}
>     ;; $bracket-apply$ of SRFI 105
>     ((_ ($bracket-apply$ container index) expr)
>
>
> with (<- ($bracket-apply$ T 2) 1) entered at toplevel i should not be in
> the third case but the first of the macro <-
>
> that is strange... i think i could not get help from mailing list on a so
> complex example that rely on my Scheme+ development for multiple values
> return (aka let-values replacment with <- ),
> sorry for the inconvenience
> Damien
>
>
> On Wed, Feb 2, 2022 at 11:33 AM Maxime Devos <maximedevos@telenet.be>
> wrote:
>
>> Damien Mattei schreef op wo 02-02-2022 om 11:13 [+0100]:
>> > (define-syntax macro
>> >   (syntax-rules ()
>> > ((_ arg1 arg2) code1)
>> > ((_ reserved-keyword arg) code2)))
>>
>> The rules are matched in-order, so when the first rule matches, the
>> second rule is ignored.  I suggest:
>>
>> (define-syntax macro
>>   (syntax-rules (reserved-keyword)
>>     ((_ reserved-keyword arg) code2)
>>     ((_ arg1 arg2) code1)))
>>
>> Greetings,
>> Maxime
>>
>>