Il giorno sab, 04/09/2021 alle 16.41 +0200, Damien Mattei ha scritto:
> hi,
>
> i have this macro:
>
> (define-syntax <+
> (syntax-rules ()
> ((_ var expr) (define var expr))
> ((_ err ...) (syntax-error "Bad <- form")) ;; does not work in
> infix !
> ))
>
> why my syntax-error pattern never reach in infix:
>
> scheme@(guile-user)> {x <+ 7 8}
> While compiling expression:
> Syntax error:
> unknown file:3:3: source expression failed to match any pattern in
> form <+
>
> but ok in prefix:
>
> scheme@(guile-user)> (<+ x 9 10)
> While compiling expression:
> Syntax error:
> unknown location: <+: Bad <- form in form (<+ x 9 10)
>
> why?
> Regards,
> Damien
As far as I understand, infix syntax can't be achieved through macros
You'd need a custom reader for that
I might be wrong, but at least I offered something
