macro_rules! impl_base_obj {
    ($base_name:ident, $type_name:ident) => {
        fn instantiate(&mut self) {
            let ty = $crate::obj::BUILTINS.with_borrow(|builtins| {
                builtins
                    .get(stringify!($type_name))
                    .expect(concat!("no ", stringify!($type_name)))
                    .clone()
            });
            self.set_attr("__ty__", ty);
            self.$base_name.instantiate();
        }

        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
        }
    };
    ($type_name:ident) => {
        impl_base_obj! { base, $type_name }
    };
}

macro_rules! impl_create {
    ($($arg:ident : $ty:ty),* $(,)?) => {
        // TODO - obj::macros::impl_create - remove this #[allow(dead_code)] designator
        #[allow(dead_code)]
        pub fn create($($arg : $ty ),*) -> $crate::obj::ObjP {
            let ptr = $crate::obj::make_ptr(Self::new($($arg),*));
            ptr.borrow_mut().instantiate();
            ptr
        }
    }
}

macro_rules! impl_do_call {
    ($name:ident) => {
        pub(crate) fn do_call(
            vm: &mut $crate::vm::Vm,
            state: $crate::obj::function::FunctionState,
        ) -> $crate::obj::function::FunctionResult {
            match state {
                $crate::obj::function::FunctionState::Begin => {
                    // get the top item off the stack and call to_float on it
                    let arg = vm.peek();
                    let method = if let Some(method) =
                        arg.borrow().get_vtable_attr(arg.clone(), stringify!($name))
                    {
                        method
                    } else {
                        // TODO builtins::do_call - throw exception when target doesn't have a
                        // to_$name method
                        // BLOCKED-ON: exceptions
                        todo!(
                            concat!("{} does not have a ", stringify!($name), " method"),
                            arg.borrow().ty_name()
                        );
                    };
                    vm.push(method.clone());
                    method.borrow().call(vm, 0);

                    // resume execution
                    $crate::obj::function::FunctionResult::Yield(0)
                }
                $crate::obj::function::FunctionState::Resume(0) => {
                    $crate::obj::function::FunctionResult::Return
                }
                _ => unreachable!(),
            }
        }
    };
}

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