bind_callback.c

#include <stdio.h>
#include <spn/ctx.h>


typedef struct {
	SpnContext *ctx;
	SpnFunction *fn;
	SpnValue arg;
} CallbackData;


static void SDL_somefunc(void (*callback)(void *), void *data)
{
	callback(data);
}

static void c_callback(void *data)
{
	CallbackData *cb_data = data;
	spn_ctx_callfunc(cb_data->ctx, cb_data->fn, NULL, 1, &cb_data->arg);
}

static int spn_sdl_somefunc(SpnValue *ret, int argc, SpnValue argv[], void *ctx)
{
	SpnFunction *fn = spn_objvalue(&argv[0]);
	CallbackData cb_data = {
		.ctx = ctx,
		.fn  = fn,
		.arg = argv[1]
	};

	SDL_somefunc(c_callback, &cb_data);
	return 0;
}

int main()
{
	SpnContext ctx;
	spn_ctx_init(&ctx);

	SpnExtFunc fn = { "somefunc", spn_sdl_somefunc };
	spn_ctx_addlib_cfuncs(&ctx, NULL, &fn, 1);

	static void *userinfo = &userinfo;
	SpnExtValue uinf = { "fake_userinfo", spn_makeweakuserinfo(userinfo) };
	spn_ctx_addlib_values(&ctx, NULL, &uinf, 1);

	spn_ctx_execstring(&ctx, "somefunc(fn (arg) { print(\"arg from within Sparkling: \", arg); }, fake_userinfo);", NULL);
	printf("actual address of fake_userinfo from C: %p\n", userinfo);

	spn_ctx_free(&ctx);
	return 0;
}