>> The second case is referencing the varible of the class.
Maybe you are right. However, I don't really think that there is a true
"reference" to the class var in example #2.
PHP documentation of static keywords does not unambiguously explain behavior
of "static" variables inside methods in example #1. I believe that in
example #1 the exactly same instance of function (method) is used
irregarding of how you call it (X::test() or Y::test()), therefore I would
expect the same "static" var to be involved in both calls to test().
Is there anybody who can comment on this matter?
Thanks.
6 июля 2011 г. 11:05 пользователь Andrew Williams <andrew4williams@xxxxxxxxx
> написал:
I think you are confusing scope visibility level of the variable within
> method and the class.
>
> Variable within the method is going to 1 because it was declare within the
> test method and there no link to the one declared outside the test method.
> The second case is referencing the varible of the class.
>
>
>
> 2011/7/6 Дмитрий Степанов <dmitrij@xxxxxxxxxxx>
>
> > Hello, everybody.
> >
> > While working with static variables inside static class' methods, I have
> > found this very interesting (at least for me) behavior of PHP.
> >
> > Consider the following class definitions (example #1):
> >
> > class X {
> > public final static function test() {
> > static $i;
> > return ++$i;
> > }
> > }
> >
> > class Y extends X {
> > }
> >
> > By executing this code:
> >
> > echo X::test();
> > echo Y::test(); // note Y class here
> >
> > one would expect to see "12" as output, but apparently I get "11".
> >
> > That's a bit confusing if you logically assume that "static vars" are
> "tied
> > to the scope" they're defined in. Since this static variable is
> > defined in a specific static method test(), that is NOT overloaded by
> class
> > Y, in my opinion it shoul've preserved it's value across static calls.
> >
> > Let's look at another example (example #2):
> >
> > class X {
> > public static $x =0;
> > public final static function test() {
> > return ++static::$x; // note static keyword here
> > }
> > }
> >
> > class Y extends X {
> > }
> >
> > If you run this code:
> >
> > echo X::test();
> > echo Y::test();
> >
> > you get "12" as output - the expected output. Notice that the
> > "++static::$x"
> > expr. is taking advantage of late static binding. Now, if you change
> > body of test() to the following code:
> >
> > public final static function test() {
> > return ++self::$x;
> > }
> >
> > then you also get "12" as output.
> >
> > Is this a bug that static context of $i is not preserved in example #1 or
> > do
> > I misunderstand something?
> >
> > I could not find any hints on this in the PHP documentation.
> >
> > Dmitry.
> >
>
--
Dmitry Stepanov
E-mail: dmitrij@xxxxxxxxxxx
Home: http://www.stepanov.lv
Skype: ninzjoo
--
Dmitry Stepanov
E-mail: dmitrij@xxxxxxxxxxx
Home: http://www.stepanov.lv
Skype: ninzjoo
