public function walkArithmeticPrimary($primary)
    {
        if ($primary instanceof AST\SimpleArithmeticExpression) {
            return '(' . $this->walkSimpleArithmeticExpression($primary) . ')';
        }

        if ($primary instanceof AST\Node) {
            return $primary->dispatch($this);
        }

        return $this->walkEntityIdentificationVariable($primary);
    }