macro_rules! impl_base_obj {
    ($base_name:ident) => {
        fn instantiate(&mut self, ty: $crate::obj::ObjP) {
            self.$base_name.instantiate(ty);
        }

        fn is_instantiated(&self) -> bool {
            self.$base_name.is_instantiated()
        }

        fn attrs(&self) -> &$crate::obj::Attrs {
            self.$base_name.attrs()
        }

        fn attrs_mut(&mut self) -> &mut $crate::obj::Attrs {
            self.$base_name.attrs_mut()
        }

        fn as_any(&self) -> &dyn std::any::Any {
            self
        }

        fn as_any_mut(&mut self) -> &mut dyn std::any::Any {
            self
        }
    };
    () => {
        impl_base_obj! { base }
    };
}

macro_rules! impl_create {
    ($($arg:ident : $ty:ty),* $(,)?) => {
        pub fn create(ty: $crate::obj::ObjP $(, $arg : $ty )*) -> $crate::obj::ObjP {
            let ptr = make_ptr(Self::new($($arg),*));
            ptr.borrow_mut().instantiate(ty);
            ptr
        }
    }
}

pub(crate) use impl_base_obj;
pub(crate) use impl_create;