OK, this is correct, I understand. But what should be output? What both print
statements should print? But implementations Guile and Chibi throws an error.

On Sun, 28 Jan 2024 15:43:08 +0100
Marc Nieper-Wißkirchen <xxxxxx@gmail.com> wrote:

> Am So., 28. Jan. 2024 um 15:09 Uhr schrieb Jakub T. Jankiewicz <
> xxxxxx@onet.pl>:
>
> > Only Racket give an error when there are no define-syntax-parameter, the
> > other implementations mention in SRFI (Guile and Chibi) doesn't require it
> > to work. So I just leave it out. The code works the same if there
> > define-syntax-parameter.
> >
>
> If an implementation allows arbitrary keywords to be syntax-parameterized,
> referential transparency of macros is violated.  E.g., some macro, say
> `when` may expand into code involving `if` and would break if `if` were
> syntax-parameterized.
>
> So what should be the output of there is define-syntax-parameter?
> >
>
> The following would be correct:
>
> (define (print x . rest)
>   (apply display x rest)
>   (newline))
>
> (define-syntax foo
>   (syntax-rules ()
>     ((_ body ...)
>      (begin
>        (define-syntax-parameter it (syntax-rules ()))
>        (syntax-parameterize
>         ((it (syntax-rules ()
>                ((_) "hello world"))))
>         (print it)
>         body ...)))))
>
> (let ((it 10))
>   (foo (print it)))
>
> The final expression would first expand into
>
> (let ((it 10))
>   (begin
>     (define-syntax-parameter it* (syntax-rules ()))
>     (syntax-parameterize
>         ((it* (syntax-rules () ((_) "hello world"))))
>       (print it*)
>       (print it)))
>
> where `it*` stands for the renamed `it`.  The expression `it*` in the line
> `(print it*)` is now a syntax error because `it*` is not valid syntax for
> the syntax-rules syntax transformer associated with `it*` (syntax-rules do
> not allow identifier syntax).  In other words, you get again undefined
> behaviour in R7RS.
>
> PS Unless you have specific reasons to stick to R7RS, you will probably be
> more helped by switching to R6RS, which doesn't have all this undefined
> behaviour that is in R7RS and where experimenting with specific
> implementations doesn't tell you much about the semantics.
>
>
>
>
> >
> > On Sun, 28 Jan 2024 13:31:27 +0100
> > Marc Nieper-Wißkirchen <xxxxxx@gmail.com> wrote:
> >
> > > Your code is an error, so any behaviour is allowed (according to the
> > > R7RS).  The problem with your code is that `syntax-parameterize` can
> > > only be applied to identifiers that are bound by
> > > `define-syntax-parameter`.
> > In
> > > your code, the identifier `it` in the macro body (which becomes
> > > hygienically renamed to, say, `it*`) is unbound.
> > >
> > >
> > > Am So., 28. Jan. 2024 um 12:46 Uhr schrieb Jakub T. Jankiewicz - jcubic
> > >
> > at
> > > onet.pl (via srfi-discuss list) <xxxxxx@srfi.schemers.org>:
> > >
> > > > Hi,
> > > >
> > > > What should be the output of this code:
> > > >
> > > > (define (print x . rest)
> > > >   (apply display x rest)
> > > >   (newline))
> > > >
> > > > (define-syntax foo
> > > >   (syntax-rules ()
> > > >     ((_ body ...)
> > > >      (begin
> > > >        (syntax-parameterize
> > > >         ((it (syntax-rules ()
> > > >                ((_) "hello world"))))
> > > >         (print it)
> > > >         body ...)))))
> > > >
> > > > (let ((it 10))
> > > >   (foo (print it)))
> > > >
> > > >
> > > > I only tested in two implementations Chibi and Guile.
> > > > Guile give an error but Chibi first print 10.
> > > >
> > > > My implementation prints 10 10.
> > > >
> > > > Jakub
> > > >
> > > > --
> > > > Jakub T. Jankiewicz, Senior Front-End Developer
> > > > https://jcubic.pl/me
> > > > https://lips.js.org
> > > > https://koduj.org
> > > >
> >
> > --
> > Jakub T. Jankiewicz, Senior Front-End Developer
> > https://jcubic.pl/me
> > https://lips.js.org
> > https://koduj.org
> >

--
Jakub T. Jankiewicz, Senior Front-End Developer
https://jcubic.pl/me
https://lips.js.org
https://koduj.org