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Bug #45728 Static references via Variable Variables
Submitted: 2008-08-06 02:00 UTC Modified: 2008-08-07 15:26 UTC
From: thinice at gmail dot com Assigned:
Status: Closed Package: Scripting Engine problem
PHP Version: 5.2.6 OS: FreeBSD
Private report: No CVE-ID: None
View Developer Edit
 [2008-08-06 02:00 UTC] thinice at gmail dot com 
Description:
------------
When you try to access a static variable within a class using a variable variable to determine which class and static to use.

Reproduce code:
---------------
<?
class MyTest {
	static $myVar = 'testval';
}

$sClass = 'MyTest';

echo "Expected output: ".MyTest::$myVar;
echo "<br/>";
$s = $sClass.'::$myVar';
echo "Using this as the string: ".$s."<br/>";
echo "Using Variable-named reference: ".${$s}; 
?>

Expected result:
----------------
Expected output: testval
Using this as the string: MyTest::$myVar
Using Variable-named reference: testval

Actual result:
--------------
Expected output: testval
Using this as the string: MyTest::$myVar
Using Variable-named reference:

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 [2008-08-07 09:53 UTC] jani@php.net 
Where exactly it says this should work..?
 [2008-08-07 15:01 UTC] thinice at gmail dot com 
You can access non-statics this way.

$myClass = 'MyClass';
echo $myClass->anythingElse;

Why wouldn't you be able to access variables via :: ?

I don't see anything on whether this should, or should not work. But why shouldn't/wouldn't it be possible to access a static variable using a variable to set the object name?
 [2008-08-07 15:07 UTC] thinice at gmail dot com 
All I can see in documentation is that you can't use :: for accessing the static from an instantiated object.

e.g.: Documentation explicitly says this will -not- work:
$myClass = new MyClass;
echo $myClass::myVar;

But this isn't the problem.
 [2008-08-07 15:16 UTC] colder@php.net 
As of PHP5.3 you can do

class A {
   public static $foo = 2;
}
$a = new A;

echo $a::$foo; // 2

$a used in a classname context will simply be converted to the class of the object.

so it's equivalent to:
$n = get_class($a);
echo $n::$foo; // 2
 [2008-08-07 15:26 UTC] thinice at gmail dot com 
You beat me to it, I just noticed the http://us.php.net/manual/en/language.oop5.paamayim-nekudotayim.php '::' page was updated for 5.3.
 
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