static variables and functions in classes?

cherries · 02-14-2008, 07:22 PM

What's the use of the static keyword for classes?

PHP Code:


			
<?php

    class Something

    {

        private static $variable = '0';

        

        private static function Test ( $variables )

        {

            // ??????

        }

    }

?>

Also I've been wondering what =& is for..

ReSpawN · 02-14-2008, 07:56 PM

I think you'll want to take a look at this page; PHP: Static Keyword - Manual

And of course the complete introduction to OOP PHP 5 is available to your as well.
PHP: Classes and Objects (PHP 5) - Manual

I have never heard about or seen the operator (assumed operator) =&, but here is a list of operators commonly used in PHP 4 and 5.

PHP Operators

Good luck.

Wildhoney · 02-14-2008, 08:07 PM

=& is merely for passing something by reference.

php Code:

$a = 5;
$b = 6;
$b =& $a; // This is where the reference is made
$a = 2;
var_dump($b); // Now equals 2 because it's a reference to "a"

ReSpawN · 02-14-2008, 08:48 PM

Thanks Wildhoney, I didn't know that. So if I understand it correctly;

PHP Code:


			
$a = 5; // Define "a" as 5
$b = 6; // Define "b" as 6
$b =& $a; // $b is now equal to the FIRST "a"
$a = 2; // "a" is redefined as 2
var_dump($b); // Since "a" was 6 and is now "2", $b is referenced to the latest 'version' of "a"

Correct? If so, thanks again.

Tanax · 02-14-2008, 09:29 PM

Quote:

Originally Posted by ReSpawN

Thanks Wildhoney, I didn't know that. So if I understand it correctly;

PHP Code:


			
$a = 5; // Define "a" as 5

$b = 6; // Define "b" as 6

$b =& $a; // $b is now equal to the FIRST "a"

$a = 2; // "a" is redefined as 2

var_dump($b); // Since "a" was 6 and is now "2", $b is referenced to the latest 'version' of "a"

Correct? If so, thanks again.

Yeap, that's correct

ReSpawN · 02-14-2008, 09:31 PM

Thanks Tanax! :)

Kalle · 02-15-2008, 02:08 PM

When declaring a property or method static they should be called outside a the class context ($this or a class instance made outside) with a double colon:

PHP Code:


			
ClassName::StaticMethod();



echo ClassName::$property;





/** Namespace */

echo NamespaceName::ClassName::$property;

and so on ;)

ReSpawN · 02-15-2008, 02:22 PM

I as well am kinda new to the OOP in PHP 5, so what does ClassName::$property do? (the dots honey)

sjaq · 02-15-2008, 03:29 PM

ClassName::$property just returns the value of $property

xenon · 02-15-2008, 07:40 PM

Just to clear something up. The ampersand operator (not the equal-ampersand operator) is used to return the memory handle of a variable/object/what ever. Therefore, all the following assignments are valid:

Code:

$a =& $x;
$a = &$x;
$a = & $x;
// and so on...

And to make it more clear, $a and $x are not equal. They just point to the same memory address. $x contains a value, while $a contains only the memory address in which the value of $x is stored.

Sounds confusing, but it's not.

cherries · 02-18-2008, 01:46 AM

Thanks a lot :)

Kalle · 02-18-2008, 02:16 PM

Quote:

Originally Posted by ReSpawN

I as well am kinda new to the OOP in PHP 5, so what does ClassName::$property do? (the dots honey)

Like sjaq said, It returns the property value and its valid in PHP4+. The reason not to use just 'ClassName::Something' is that from PHP5 they are constants.

The double colon or 'Paamayim Nekudotayim' (Double colon in hebrew, PHP only) is simply the way of calling static methods, theres some information about it on the PHP manual here:
PHP: Scope Resolution Operator (::) - Manual