Commit 806ea1f6 authored by Paul Sokolovsky's avatar Paul Sokolovsky
Browse files

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.
parent 0c937fa2
......@@ -33,6 +33,8 @@
#include "obj.h"
#include "runtime0.h"
mp_obj_t instance_make_new(mp_obj_t self_in, uint n_args, uint n_kw, const mp_obj_t *args);
typedef struct _mp_obj_object_t {
mp_obj_base_t base;
} mp_obj_object_t;
......@@ -52,12 +54,23 @@ STATIC mp_obj_t object___init__(mp_obj_t self) {
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(object___init___obj, object___init__);
STATIC mp_obj_t object___new__(mp_obj_t cls) {
mp_obj_t o = MP_OBJ_SENTINEL;
mp_obj_t res = instance_make_new(cls, 1, 0, &o);
return res;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(object___new___fun_obj, object___new__);
STATIC MP_DEFINE_CONST_STATICMETHOD_OBJ(object___new___obj, (const mp_obj_t)&object___new___fun_obj);
#endif
STATIC const mp_map_elem_t object_locals_dict_table[] = {
#if MICROPY_CPYTHON_COMPAT
{ MP_OBJ_NEW_QSTR(MP_QSTR___init__), (mp_obj_t)&object___init___obj },
#endif
#if MICROPY_CPYTHON_COMPAT
{ MP_OBJ_NEW_QSTR(MP_QSTR___new__), (mp_obj_t)&object___new___obj },
#endif
};
STATIC MP_DEFINE_CONST_DICT(object_locals_dict, object_locals_dict_table);
......
......@@ -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);
......
class A:
@staticmethod
def __new__(cls):
print("A.__new__")
return super(cls, A).__new__(cls)
def __init__(self):
pass
def meth(self):
pass
#print(A.__new__)
#print(A.__init__)
a = A()
#print(a.meth)
#print(a.__init__)
#print(a.__new__)
# object.__new__(cls) is the only way in Python to allocate empty
# (non-initialized) instance of class.
# See e.g. http://infohost.nmt.edu/tcc/help/pubs/python/web/new-new-method.html
# TODO: Find reference in CPython docs
class Foo:
def __init__(self):
print("in __init__")
self.attr = "something"
o = object.__new__(Foo)
#print(o)
print(hasattr(o, "attr"))
print(isinstance(o, Foo))
o.__init__()
#print(dir(o))
print(hasattr(o, "attr"))
print(o.attr)
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