Edit report at http://bugs.php.net/bug.php?id=53081&edit=1
ID: 53081
Comment by: giorgio dot liscio at email dot it
Reported by: giorgio dot liscio at email dot it
Summary: why you should bring back abstract static methods
Status: Bogus
Type: Feature/Change Request
Package: Class/Object related
PHP Version: 5.3.3
Block user comment: N
New Comment:
i know, but:
abstract class cA
{
//static function A(){self::B();} error, undefined method
static function A(){static::B();} // good
abstract static function B();
}
class cB extends cA
{
static function B(){echo "ok";}
}
cB::A();
Previous Comments:
------------------------------------------------------------------------
[2010-10-16 08:27:01] [email protected]
No, you are calling a method in an abstract class. The fundamental
characteristic
of an abstract class is that you cannot call methods in them.
------------------------------------------------------------------------
[2010-10-16 08:15:46] giorgio dot liscio at email dot it
hi Rasmus, what an honor!
can you please give me some example code?
you are saying that self:: points to an abstract not-implemented
method?
for example:
abstract class cA
{
static function A(){self::B();}
abstract static function B();
}
in this case can be thrown an error, but using static:: the call refers
to the called class method, not the declaring class
static function A(){static::B();}
so it can be re-enabled in this case, no?
in php static methods are really powerful unlike java's, c#'s, don't
limit them!
why interfaces allows static abstract methods? how self:: is resolved?
------------------------------------------------------------------------
[2010-10-16 07:21:47] [email protected]
Sorry, I re-read that explanation, that didn't make sense. I meant to
say that
methods in an abstract class require that any instance of that class
implement
those methods, but static methods belong to the class, not an instance.
You can't
call methods from an abstract class, you can only call them in instances
of that
class, but static methods by definition belong to the class, but since
you can't
call methods in an abstract class you could never call these static
methods so
there is no point in them being there.
------------------------------------------------------------------------
[2010-10-16 07:15:35] [email protected]
A static method belongs to the class, not to an instance of that class
and since
you can't have an instance of an abstract class, static methods make no
sense in
abstract classes. It is really that simple.
------------------------------------------------------------------------
[2010-10-16 06:58:55] giorgio dot liscio at email dot it
sorry, corrected code:
abstract class FSItem
{
protected function __construct($path){}
// random per-item singleton
public static function getByPath($path)
{
if(static::isPathValid($path)) // here is the static method
call of classes. i want to check the path before instance it
return new static($path);
}
// abstract static method:
abstract protected static function isPathValid($path);
}
class Dir extends FSItem
{
//implementation:
protected static function isPathValid($path)
{
return is_dir($path);
}
}
class File extends FSItem
{
//implementation:
protected static function isPathValid($path)
{
return is_file($path);
}
}
class Image extends File
{
//implementation:
protected static function isPathValid($path)
{
return (bool)getimagesize($path);
}
}
------------------------------------------------------------------------
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