Re: with-syntax return error in Guile, not in Kawa or Racket

[Damien Mattei]

i understand Jean, do you have an idea to fix this macro, i'm not far away
from the result as the display show it

i'm modifying a macro that worked but i want to write it in a more modern
way (macro talking), this do the same than in Python in this example:
Python 3.11.2 (v3.11.2:878ead1ac1, Feb  7 2023, 10:02:41) [Clang 13.0.0
(clang-1300.0.29.30)] on darwin
Type "help", "copyright", "credits" or "license()" for more information.

[0, 1 ,2 ,3, 4, 5,6 ,8,9][6 - 4 : 5 + 2]
[2, 3, 4, 5, 6]

the guile output:

scheme@(guile-user)> {#(1 2 3 4 5 6 7 8 9)[6 - 4 : 5 + 2]}
$bracket-apply$ : parsed-evaluated-args=((- 6 4) : (+ 5 2))
While compiling expression:
Syntax error:
unknown file:#f:#f: encountered raw symbol in macro output in subform - of
($bracket-apply$ #(1 2 3 4 5 6 7 8 9) 6 - 4 : 5 + 2)
scheme@(guile-user)> '{#(1 2 3 4 5 6 7 8 9)[6 - 4 : 5 + 2]}
$1 = ($bracket-apply$ #(1 2 3 4 5 6 7 8 9) 6 - 4 : 5 + 2)
scheme@(guile-user)> ($bracket-apply$ #(1 2 3 4 5 6 7 8 9) 6 - 4 : 5 + 2)
$bracket-apply$ : parsed-evaluated-args=((- 6 4) : (+ 5 2))
While compiling expression:
Syntax error:
unknown file:#f:#f: encountered raw symbol in macro output in subform - of
($bracket-apply$ #(1 2 3 4 5 6 7 8 9) 6 - 4 : 5 + 2)

as you can see i have the good syntax from infix to prefix:
$bracket-apply$ : parsed-evaluated-args=((- 6 4) : (+ 5 2))
how can i make the macro result be what i want, here is the actual one:

(define-syntax $bracket-apply$

  (lambda (stx)

    (syntax-case stx ()

      (($bracket-apply$ container . args-brackets)

       (with-syntax ((parsed-evaluated-args
(optimizer-parse-square-brackets-arguments-lister (syntax->datum
#'args-brackets))))
 (display "$bracket-apply$ : parsed-evaluated-args=") (display
#'parsed-evaluated-args) (newline)

#'($bracket-apply$next4list-args container parsed-evaluated-args))))))

a working solution was:

{#(1 2 3 4 5 6 7)[2 * 5 - 8 : 3 * 5 - 10]}
'#(3 4 5)

{#(1 2 3 4 5 6 7)[2 * 5 - 8 : 3 * 5 - 10 : 2 * 4 - 6]}
'#(3 5)
scheme@(guile-user)> {#(1 2 3 4 5 6 7 8 9)[6 - 4 : 5 + 2]}
$bracket-apply$ : args-brackets=(6 #<procedure - (#:optional _ _ . _)> 4 :
5 #<procedure + (#:optional _ _ . _)> 2)
$1 = #(3 4 5 6 7)
scheme@(guile-user)> {#(1 2 3 4 5 6 7 8 9)[2 * 3 - 4 : 2 * 5 - 3]}
$bracket-apply$ : args-brackets=(2 #<procedure * (#:optional _ _ . _)> 3
#<procedure - (#:optional _ _ . _)> 4 : 2 #<procedure * (#:optional _ _ .
_)> 5 #<procedure - (#:optional _ _ . _)> 3)
$2 = #(3 4 5 6 7)
(define ($bracket-apply$ container . args-brackets)  ;;  this implements a
possible $bracket-apply$ as proposed in SRFI-105

  ;;(display "$bracket-apply$ : args-brackets=") (display args-brackets)
(newline)
  ;;(display "$bracket-apply$ : infix-operators-lst=") (display
infix-operators-lst) (newline)
  ($bracket-apply$next4list-args container
  (optimizer-parse-square-brackets-arguments-evaluator args-brackets)))

but i want to avoid optimizer-parse-square-brackets-arguments-evaluator at
run time , i prefer to use optimizer-parse-square-brackets-arguments-lister
at a macro stage earlier ,so not rexecuted at each computation, but this an
idea, perheaps not pertinent...

sorry for long, obscure mail...



On Sun, May 5, 2024 at 2:48 PM Jean Abou Samra <jean@abou-samra.fr> wrote:

>
> > (base) mattei@mbp-touch-bar Scheme-PLUS-for-Guile % guile
> > GNU Guile 3.0.8.99-f3ea8
> > Copyright (C) 1995-2022 Free Software Foundation, Inc.
> >
> > Guile comes with ABSOLUTELY NO WARRANTY; for details type `,show w'.
> > This program is free software, and you are welcome to redistribute it
> > under certain conditions; type `,show c' for details.
> >
> > Enter `,help' for help.
> > scheme@(guile-user)> (define-syntax test-it
> >    (lambda (stx)
> >     (syntax-case stx ()
> >     ((_ term1)
> >      (with-syntax ((var (syntax->datum #'term1)))
> >        #'var)))))
> > scheme@(guile-user)> (test-it (+ 2 3))
> > While compiling expression:
> > Syntax error:
> > unknown file:#f:#f: encountered raw symbol in macro output in subform +
> of
> > (test-it (+ 2 3))
>
>
> As the error message says, your macro contains the raw symbol `term1`.
> The expression (syntax->datum #'term1) is equivalent to 'term1 .
> What's raising the error is not with-syntax itself, it's the fact
> that a hygienic macro must return syntax objects, and a raw
> symbol is not a syntax object. Kawa and Racket probably have some
> fallback where the macro becomes non-hygienic when it returns
> raw symbols. But R6RS makes it clear that this is not standard
> Scheme. See
>
> https://www.r6rs.org/final/html/r6rs-lib/r6rs-lib-Z-H-13.html#node_sec_12.2
>
> """
> a syntax object is:
>
> - a pair of syntax objects,
> - a vector of syntax objects,
> - a nonpair, nonvector, nonsymbol value, or
> - a wrapped syntax object
> """
>
> """
> A transformation procedure is a procedure that must accept one argument, a
> wrapped syntax object (section 12.2) representing the input, and return a
> syntax
> object (section 12.2) representing the output.
> """
>
>
>