Re: error Wrong type to apply: #<syntax-transformer

[Damien Mattei]

i know what disturb me in this error, it is because the order of
definitions has effect but i always learn (was it right?) that in
scheme the order of definitions should have no effect on the resulting
evaluations.

On Thu, Aug 3, 2023 at 1:01 PM Damien Mattei <damien.mattei@gmail.com> wrote:
>
> thank you
> it is clear now , even if i really never find the macro needed upward
> i tested too in racket your example and the messages is simple to understand :
>
> Welcome to DrRacket, version 8.9 [cs].
> Language: reader
> "../Scheme-PLUS-for-Racket/main/Scheme-PLUS-for-Racket/SRFI/SRFI-105.rkt",
> with debugging; memory limit: 8192 MB.
> '()
> > foo
> foo: undefined;
>  cannot reference an identifier before its definition
> > bar
> bar: undefined;
>  cannot reference an identifier before its definition
> > (define (foo)
>   (bar 'quux))
> > (define-syntax-rule (bar x) x)
> > (display (foo))
> . . ../../../../../../../Applications/Racket
> v8.9/collects/racket/private/kw.rkt:1263:25: bar: undefined;
>  cannot reference an identifier before its definition
>
> On Thu, Aug 3, 2023 at 11:58 AM Jean Abou Samra <jean@abou-samra.fr> wrote:
> >
> > overload.scm must be before some definitions of scheme-infix.scm even
> > if it is not used here, it is strange, i do not understand all but it
> > compiles now
> >
> >
> >
> > A minimal reproducer for your problem is
> >
> > (define (foo)
> >   (bar 'quux))
> > (define-syntax-rule (bar x) x)
> > (display (foo))
> >
> >
> > Let's dissect what happens. At macro expansion time (during byte 
> > compilation), first the definition of foo is expanded. bar is unbound, so 
> > it's compiled as a function call. Then comes the definition of bar as a 
> > macro, but foo has already been expanded without it.
> >
> > At runtime, a macro is bound to a syntax transformer, so the binding for 
> > bar that was unresolved at expand time gets resolved to the toplevel 
> > binding that gets defined for bar, and you get this error because a macro 
> > transformer can't be called as  a function.
> >
> >