Micropython User Module: Class Prints Initialized Data Even If Attributes Have Changed - c++

Question

Here's a visual representation of the problem from the front end. Notice that the output from printing the class does not change even if the attributes do, yet I get the proper value from printing the attributes directly.
import bitbanglab as bbl
class Entity(bbl.Entity):
def __init__(self):
super().__init__(bytearray([0x0F]), 1, 1, 2, 2, 8, 2)
print(self) #Entity(x:1, y:1, width:2, height:2, scale:8, len:1, pal:2)
self.x = 50
self.y = 20
self.width = 50
self.height= 60
self.scale = 10
self.len = 200
self.pal = 14
print(self) #Entity(x:1, y:1, width:2, height:2, scale:8, len:1, pal:2)
print(self.x) #50
print(self.y) #20
Entity()
Print Method
STATIC void Entity_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
(void)kind;
bitbanglab_Entity_obj_t *self = MP_OBJ_TO_PTR(self_in);
mp_printf(print, "Entity(x:%u, y:%u, width:%u, height:%u, scale:%u, len:%u, pal:%u)", self->x, self->y, self->width, self->height, self->scale, self->len, self->pal);
}
get/set attributes
STATIC void Entity_attr(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
bitbanglab_Entity_obj_t *self = MP_OBJ_TO_PTR(self_in);
if (dest[0] == MP_OBJ_NULL) {
if (attr == MP_QSTR_x)
dest[0] = mp_obj_new_int(self->x);
else if(attr == MP_QSTR_y)
dest[0] = mp_obj_new_int(self->y);
else if(attr == MP_QSTR_width)
dest[0] = mp_obj_new_int(self->width);
else if(attr == MP_QSTR_height)
dest[0] = mp_obj_new_int(self->height);
else if(attr == MP_QSTR_scale)
dest[0] = mp_obj_new_int(self->scale);
else if(attr == MP_QSTR_len)
dest[0] = mp_obj_new_int(self->len);
else if(attr == MP_QSTR_pal)
dest[0] = mp_obj_new_int(self->pal);
} else {
if (attr == MP_QSTR_x)
self->x = mp_obj_get_int(dest[1]);
else if (attr == MP_QSTR_y)
self->y = mp_obj_get_int(dest[1]);
else if (attr == MP_QSTR_width)
self->width = mp_obj_get_int(dest[1]);
else if (attr == MP_QSTR_height)
self->height = mp_obj_get_int(dest[1]);
else if (attr == MP_QSTR_scale)
self->scale = mp_obj_get_int(dest[1]);
else if (attr == MP_QSTR_len)
self->len = mp_obj_get_int(dest[1]);
else if (attr == MP_QSTR_pal)
self->pal = mp_obj_get_int(dest[1]);
dest[0] = MP_OBJ_NULL;
}
}
Class Type
const mp_obj_type_t bitbanglab_Entity_type = {
{ &mp_type_type },
.name = MP_QSTR_bitbanglab,
.print = Entity_print,
.make_new = Entity_make_new,
.locals_dict = (mp_obj_dict_t*)&Entity_locals_dict,
.attr = Entity_attr,
};
Class Object
typedef struct _bitbanglab_Entity_obj_t {
mp_obj_base_t base;
uint8_t *bitmap;
uint16_t len;
uint16_t x;
uint16_t y;
uint16_t width;
uint16_t height;
uint8_t scale;
uint8_t pal;
} bitbanglab_Entity_obj_t;
Class
The class doesn't have any methods yet. The locals_dict_table for it is empty.
mp_obj_t Entity_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
mp_arg_check_num(n_args, n_kw, 7, 7, true);
//make self
bitbanglab_Entity_obj_t *self = m_new_obj(bitbanglab_Entity_obj_t);
self->base.type = &bitbanglab_Entity_type;
//arguments
enum { ARG_bitmap, ARG_x, ARG_y, ARG_width, ARG_height, ARG_scale, ARG_pal};
//get buffer
mp_buffer_info_t bufinfo;
mp_get_buffer_raise(args[ARG_bitmap], &bufinfo, MP_BUFFER_RW);
//properties
self->bitmap = (uint8_t *)bufinfo.buf;
self->len = bufinfo.len;
self->x = mp_obj_get_int(args[ARG_x]);
self->y = mp_obj_get_int(args[ARG_y]);
self->width = mp_obj_get_int(args[ARG_width]);
self->height = mp_obj_get_int(args[ARG_height]);
self->scale = mp_obj_get_int(args[ARG_scale]);
self->pal = mp_obj_get_int(args[ARG_pal]);
return MP_OBJ_FROM_PTR(self);
}

Answer 1

I realized the problem. I was subclassing my user-module-defined class, and the values I was setting were not the ones on the super. If I instantiate the Entity class without a subclass and change the attributes, printing the class reflects those changes. Now my new problem is figuring out how to reach the super's attributes from a subclass. I'll update this answer to be stronger when I figure it all out.