Re: Suggestion on static field inheritance

2009/5/16 Jingcheng Zhang <diogin@gmail.com>: > > Maybe I have not found its detailed description on PHP's official manual, > but PHP does allow static field inheritance. However there is a little > difference between dynamic field inheritance and static field inheritance, > as the following codes shows: Hi! I think the current behaviour is as expected. In that example, there is a single static field which is shared between classes static_a, static_b and static_c. Because there is just one value of $name, the class through which you access the value makes no difference. On the other hand, in the case of classes dynamic_a, dynamic_b and dynamic_c, by the nature of instance properties, each instance has its own value of $name. So changing the value in one instance does not affect the others. This behaviour is similar to many other OO languages, including Java, C++ and C#. Perhaps a closer equivalent of the Javascript code you provided is as follows, where the static field is re-declared in subclasses, and therefore exists as a separate entity in each class. Again, this distinction between inherited static fields and "re-declared" static fields also applies to other languages such as Java, C++ and C#. <?php class static_a { public static function change($name) { static::$name = $name; } public static $name = 'a'; } class static_c extends static_a { public static $name; } class static_d extends static_a { public static $name; } echo static_a::$name; // a static_c::change('c'); echo static_a::$name; // a static_d::change('d'); echo static_a::$name; // a ?> What do you think? Regards, Robin