public function evaluateRule($fieldValue)
    {
        // what type of variable are we dealing with?
        // todo maybe pick and choose when to treat variable as string
        $testFunction = "return ('" . $fieldValue . "' $this->operator  '$this->value' ) ? true : false ;";
        $result = eval($testFunction);
        if (!is_bool($result)) {
            throw new HTTPException('DenyIf rule returned invalid result.  Must be a boolean', 500, ['code' => '136497941613689198']);
        }
        return $result;
    }