Re: [Chicken-users] foreign functions, swig

[John Lenz]

On Sat, 2006-05-20 at 14:18 -0700, Dan wrote:
> Thanks. I ended up writing SWIG typemaps (which I'm
> providing below, for those interested; no checks for
> now). I really think these should have been provided
> by SWIG, though...

> typedef unsigned int size_t;

You can do something like %apply unsigned int size_t; as well

> 
> %typemap(in) float * {
>   $1 = C_c_f32vector_or_null ($input);
> }
> 
> %typemap(in) double * {
>   $1 = C_c_f64vector_or_null ($input);
> }
> 
> %typemap(in) int * {
>   $1 = C_c_s32vector_or_null ($input);
> }
> 
> %typemap(in) unsigned * {
>   $1 = C_c_u32vector_or_null ($input);
> }
> 
> %typemap(in) long * {
>   $1 = C_c_s32vector_or_null ($input);
> }
> 
> %typemap(in) unsigned long * {
>   $1 = C_c_u32vector_or_null ($input);
> }

I was thinking about these, and I think should define something like

%typemap(in) unsigned int *u32vector {
  $1 = C_c_u32vector_or_null($input);
}

(That is, give the typemap a name of u32vector.)  Then to use the
typemap, you need to do something like

%apply unsigned int *u32vector { unsigned int *vec };

void test(unsigned int *vec) {
...
}

And then optionally %clear unsigned int *vec;

This way, including srfi4.i does not corrupt the global namespace of
typemaps.  If you actually want to pass a double * somewhere as an
actual pointer, and not an array, you don't have to do anything.  This
is how argout/argin typemaps work, you apply the unsigned int *OUTPUT
typemap to whatever you want to be an output argument.

If you just want to apply the typemap to everything, you can do
something like

%clear unsigned int *;
%apply unsigned int *u32vector { unsigned int * };

(You need the clear because %apply never overwrites existing typemaps)

What do you think about using this kind of interface?

John