picrin_cffi_example.c

/*
 * C-side API
 */

struct my_data {
  // blah blah blah
};

struct my_data *
create_my_data ()
{
  return malloc(sizeof(struct my_data));
}

void
finalize_my_data (void *my_data) {
  struct my_data *md = my_data;
  free(md);
}


/*
 * picrin-side FFI interface
 */

static const pic_data_type my_data = { "my-data", finalize_my_data };

static pic_value
pic_create_my_data(pic_state *pic)
{
  struct my_data *md;
  struct pic_data *dat;
  
  pic_get_args(pic, ""); // no args here
  
  md = create_my_data();
  
  data = pic_data_alloc(pic, &my_data, md);
  
  return pic_obj_value(data);
}

void
pic_init_my_data(pic_state *pic)
{
  pic_defun(pic, "create-my-data", pic_create_my_data); // (create-my-data)
}


// at last you need to modify src/init.c to call my pic_init_my_data.
// I should have made a cmake hook to call this kind of extension initializers
// but I forgot about the detail...
// When I remember or write it up from scratch, I'll revise this tutorial.