py/objtype: Support passing in an OrderedDict to type() as the locals.

An OrderedDict can now be used for the locals when creating a type
explicitly via type(name, bases, locals).

Signed-off-by: Damien George <damien@micropython.org>

py/objtype.c

@@ -153,7 +153,7 @@ STATIC void mp_obj_class_lookup(struct class_lookup_data *lookup, const mp_obj_t
 
         if (type->locals_dict != NULL) {
             // search locals_dict (the set of methods/attributes)
-            assert(type->locals_dict->base.type == &mp_type_dict); // MicroPython restriction, for now
+            assert(mp_obj_is_dict_or_ordereddict(MP_OBJ_FROM_PTR(type->locals_dict))); // MicroPython restriction, for now
             mp_map_t *locals_map = &type->locals_dict->map;
             mp_map_elem_t *elem = mp_map_lookup(locals_map, MP_OBJ_NEW_QSTR(lookup->attr), MP_MAP_LOOKUP);
             if (elem != NULL) {
@@ -1053,7 +1053,7 @@ STATIC void type_attr(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
         // delete/store attribute
 
         if (self->locals_dict != NULL) {
-            assert(self->locals_dict->base.type == &mp_type_dict); // MicroPython restriction, for now
+            assert(mp_obj_is_dict_or_ordereddict(MP_OBJ_FROM_PTR(self->locals_dict))); // MicroPython restriction, for now
             mp_map_t *locals_map = &self->locals_dict->map;
             if (locals_map->is_fixed) {
                 // can't apply delete/store to a fixed map
@@ -1103,7 +1103,7 @@ mp_obj_t mp_obj_new_type(qstr name, mp_obj_t bases_tuple, mp_obj_t locals_dict)
     if (!mp_obj_is_type(bases_tuple, &mp_type_tuple)) {
         mp_raise_TypeError(NULL);
     }
-    if (!mp_obj_is_type(locals_dict, &mp_type_dict)) {
+    if (!mp_obj_is_dict_or_ordereddict(locals_dict)) {
         mp_raise_TypeError(NULL);
     }
 

tests/basics/class_ordereddict.py

@@ -0,0 +1,18 @@
+# test using an OrderedDict as the locals to construct a class
+
+try:
+    from ucollections import OrderedDict
+except ImportError:
+    try:
+        from collections import OrderedDict
+    except ImportError:
+        print("SKIP")
+        raise SystemExit
+
+if not hasattr(int, "__dict__"):
+    print("SKIP")
+    raise SystemExit
+
+
+A = type("A", (), OrderedDict(a=1, b=2, c=3, d=4, e=5))
+print([k for k in A.__dict__.keys() if not k.startswith("_")])

tests/basics/class_ordereddict.py.exp

@@ -0,0 +1 @@
+['a', 'b', 'c', 'd', 'e']