... about language-independent design considerations. But what is apackage in programming terms in PHP? How do we implement it? Since there is nopackage, module, or subsystem concept in PHP 5, there ... clearer in practice. Unit testing and refactoring (improving the design of existing code) areways to improve the quality of software, making it easier to maintain and allowing usto prevent bugs. ... represen-tations of single times, and representations of time spans or intervals. In the rest of thissection, we’ll study these two categories in turn.8.2.1 Single time representation: Time Point, Instant,...