Re: Suggestion on static field inheritance

Nobody is interested in this topic? Another confusing feature is "static function", which is allowed in interface, but not allowed in abstract class, any explanation or reason for this? Thanks :-) 2009/5/16 Jingcheng Zhang <diogin@gmail.com> > Hello all, > > 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: > > <?php > class static_a { > public static function change($name) { > self::$name = $name; > } > public static $name = 'a'; > } > class static_c extends static_a {} > class static_d extends static_a {} > > echo static_a::$name; // a > static_c::change('c'); > echo static_a::$name; // c > static_d::change('d'); > echo static_a::$name; // d > > > class dynamic_a { > public function change($name) { > $this->name = $name; > } > public $name = 'a'; > } > class dynamic_c extends dynamic_a {} > class dynamic_d extends dynamic_a {} > > $a = new dynamic_a(); > $c = new dynamic_c(); > $d = new dynamic_d(); > echo $a->name; // a > $c->change('c'); > echo $a->name; // a > $d->change('d'); > echo $a->name; // a > ?> > > The result of static inheritance test can be meaningful on some > way(especially on class-based programming perspective), but when considering > the static class as "object" in prototype-based programming(which I doubt is > some people's favourite who comes from prototype-based OOP community), this > result can be confusing. On JavaScript, this example can be: > > <script type="text/javascript"> > function extends(parent) { > var T = function () {}; > T.prototype = parent; > return new T(); > } > var static_a = { > name: 'a', > change: function (name) { > this.name = name; > } > }; > var static_c = extends(static_a); > var static_d = extends(static_a); > > alert(static_a.name); // a > static_c.change('c'); > alert(static_a.name); // a > static_d.change('d'); > alert(static_a.name); // a > </script> > > This looks more meaningful. So my suggestion is, could PHP's static > inheritance rule follow the dynamic inheritance rule ( $this on dynamic, or > prototype delegation on JavaScript) ? > Thanks :-) > > -- > Best regards, > Jingcheng Zhang > P.R.China > -- Best regards, Jingcheng Zhang Room 304, Dormitory 26 of Yuquan Campus, Zhejiang University P.R.China