py: Initial attempts to actually allow implementing __new__ in Python.

Caveat is that __new__ should recurse to base class __new__, and ultimately,
object.__new__ is what handles instance allocation.

1 files changed, 10 insertions, 2 deletions

diff --git a/py/objtype.c b/py/objtype.c
index 5da49a045..1d4f90819 100644
--- a/py/objtype.c
+++ b/py/objtype.c
@@ -51,7 +51,7 @@
 
 #define is_instance_type(type) ((type)->make_new == instance_make_new)
 #define is_native_type(type) ((type)->make_new != instance_make_new)
-STATIC mp_obj_t instance_make_new(mp_obj_t self_in, uint n_args, uint n_kw, const mp_obj_t *args);
+mp_obj_t instance_make_new(mp_obj_t self_in, uint n_args, uint n_kw, const mp_obj_t *args);
 STATIC void instance_convert_return_attr(mp_obj_t self, const mp_obj_type_t *type, mp_obj_t member, mp_obj_t *dest);
 
 STATIC mp_obj_t mp_obj_new_instance(mp_obj_t class, uint subobjs) {
@@ -208,7 +208,7 @@ STATIC void instance_print(void (*print)(void *env, const char *fmt, ...), void
     print(env, "<%s object at %p>", mp_obj_get_type_str(self_in), self_in);
 }
 
-STATIC mp_obj_t instance_make_new(mp_obj_t self_in, uint n_args, uint n_kw, const mp_obj_t *args) {
+mp_obj_t instance_make_new(mp_obj_t self_in, uint n_args, uint n_kw, const mp_obj_t *args) {
     assert(MP_OBJ_IS_TYPE(self_in, &mp_type_type));
     mp_obj_type_t *self = self_in;
 
@@ -218,6 +218,14 @@ STATIC mp_obj_t instance_make_new(mp_obj_t self_in, uint n_args, uint n_kw, cons
 
     mp_obj_instance_t *o = mp_obj_new_instance(self_in, num_native_bases);
 
+    // This executes only "__new__" part of obejection creation.
+    // TODO: This won't work will for classes with native bases.
+    // TODO: This is hack, should be resolved along the lines of
+    // https://github.com/micropython/micropython/issues/606#issuecomment-43685883
+    if (n_args == 1 && *args == MP_OBJ_SENTINEL) {
+        return o;
+    }
+
     // look for __new__ function
     mp_obj_t init_fn[2] = {MP_OBJ_NULL};
     mp_obj_class_lookup(NULL, self, MP_QSTR___new__, offsetof(mp_obj_type_t, make_new), init_fn);