call Class#initialize from Class.new; ref ISO 15.2.3.3.1

src/class.c

@@ -1094,19 +1094,31 @@ mrb_obj_new(mrb_state *mrb, struct RClass *c, mrb_int argc, const mrb_value *arg
   return obj;
 }
 
+static mrb_value
+mrb_class_initialize(mrb_state *mrb, mrb_value c)
+{
+  mrb_value a, b;
+
+  mrb_get_args(mrb, "|C&", &a, &b);
+  if (!mrb_nil_p(b)) {
+    mrb_yield_with_class(mrb, b, 1, &c, c, mrb_class_ptr(c));
+  }
+  return c;
+}
+
 static mrb_value
 mrb_class_new_class(mrb_state *mrb, mrb_value cv)
 {
+  mrb_int n;
   mrb_value super, blk;
   mrb_value new_class;
 
-  if (mrb_get_args(mrb, "|C&", &super, &blk) == 0) {
+  n = mrb_get_args(mrb, "|C&", &super, &blk);
+  if (n == 0) {
     super = mrb_obj_value(mrb->object_class);
   }
   new_class = mrb_obj_value(mrb_class_new(mrb, mrb_class_ptr(super)));
-  if (!mrb_nil_p(blk)) {
-    mrb_yield_with_class(mrb, blk, 1, &new_class, new_class, mrb_class_ptr(new_class));
-  }
+  mrb_funcall_with_block(mrb, new_class, mrb_intern_lit(mrb, "initialize"), n, &super, blk);
   mrb_funcall(mrb, super, "inherited", 1, new_class);
   return new_class;
 }
@@ -1963,9 +1975,10 @@ mrb_init_class(mrb_state *mrb)
   mrb_define_method(mrb, bob, "!",                       mrb_bob_not,              MRB_ARGS_NONE());
   mrb_define_method(mrb, bob, "method_missing",          mrb_bob_missing,          MRB_ARGS_ANY());  /* 15.3.1.3.30 */
 
-  mrb_define_class_method(mrb, cls, "new",               mrb_class_new_class,      MRB_ARGS_ANY());
+  mrb_define_class_method(mrb, cls, "new",               mrb_class_new_class,      MRB_ARGS_OPT(1));
   mrb_define_method(mrb, cls, "superclass",              mrb_class_superclass,     MRB_ARGS_NONE()); /* 15.2.3.3.4 */
   mrb_define_method(mrb, cls, "new",                     mrb_instance_new,         MRB_ARGS_ANY());  /* 15.2.3.3.3 */
+  mrb_define_method(mrb, cls, "initialize",              mrb_class_initialize,     MRB_ARGS_OPT(1)); /* 15.2.3.3.1 */
   mrb_define_method(mrb, cls, "inherited",               mrb_bob_init,             MRB_ARGS_REQ(1));
 
   MRB_SET_INSTANCE_TT(mod, MRB_TT_MODULE);