Re: Parameterizing inline C code

On Sun, Mar 09, 2025 at 08:46:08PM +0100, felix.winkelmann--- via Chicken-users wrote:
> > the syntax #> ... <# allows us to inline C code in CHICKEN code. Can I
> > "parameterize" it?
> >
> > I'd like to have something like this:
> >
> >     (begin-for-syntax
> >         (define count 0)
> >
> >         (define (foo-transformer x r c)
> >           (let ((name (generate-function-name x)))
> >             #>
> >             void ,name(void) {
> >                 printf("hello world: %s\n", c_special_func(,name));
> >             }
> >             <#
> >         )
> >     )
> >
> >     (define-syntax foo
> >       (er-macro-transformer foo-transformer))
> >
> >     (foo 1) ;; creates void foo_1(void) {...}
> >     (foo 2) ;; creates void foo_2(void) {...}
> >     ...
> >
> > I know that using define-external I could define a function foo_n and then
> > using foreign-safe-lambda* in the function definition of define-external
> > I could adapt the body as well. But that will add a lot of CHICKEN
> > bookkeeping and function calls. In my case I really just want a plain
> > C function to be generated.
> 
> "#> ... <#" is just sugar for "foreign-declare", so nothing prevents you from
> having a macro that constructs a string of arbitrary C code and expanding
> into a "foreign-declare" form. In the example above, you would probably
> replace the inner #> ... <# with something like
> 
> 	(let ((fd (r 'foreign-declare)))
> 	  `(,fd ,(format "void ~a(void) { ... }" name)))

That is excellent! I looked up the documentation for something like that 
but somehow simply missed it. Thank you.