|
|
Posted by Rik Wasmus on 01/24/08 23:09
On Thu, 24 Jan 2008 22:48:44 +0100, Johannes Permoser <ee_pp@yahoo.de> =
wrote:
> Hi,
>
> i have a class that calls a static function:
>
> class Peter
> {
> static function foo() {echo 123;}
> =
> public static function bar ()
> {
> Peter::foo();
> }
> }
>
> $p =3D new Peter();
> $p->bar();
>
> Now i want to extend the class and override the foo() function. Howeve=
r =
> when calling bar(), it will still execute the code defined in Peter an=
d =
> not the override. I tried $this::foo(), but it doesn't work.
Peter::foo() will always call the static method from the class Peter, no=
t =
PetersChild, as it directly calls a static class, which might as well be=
=
ADifferentClassAllTogether::foo()
Now, if you'd have used 'self', some more explanation would be required:=
<?php
class Peter
{
static function foo() {echo 123;}
=
public static function bar ()
{
self::foo();
}
}
class PetersChild extends Peter
{
static function foo(){echo 456;}
}
PetersChild::bar();
?>
Result: still 123
However, some juicy details:
<?php
class Peter
{
static function foo() {echo 123;}
=
public static function bar ()
{
self::foo();
}
public function foz(){
self::foo();
$this->foo();
}
}
class PetersChild extends Peter
{
static function foo(){echo 456;}
}
$a =3D new PetersChild();
$a->foz();
?>
Results in '123456'.
In short: self in a class is solved at compilation as far as I gather, a=
nd =
hence will point to the parent class, not the child class. $his is an =
instance of a class, and its methods/function are more clear. What some =
=
people want is late static binding, which will be possible from PHP5.3 =
using the static::, see =
http://nl3.php.net/manual/en/language.oop5.late-static-bindings.php
-- =
Rik Wasmus
Navigation:
[Reply to this message]
|