Access a static variable by $var::$reference

Question

I am trying to access a static variable within a class by using a variable class name. I'm aware that in order to access a function within the class, you use call_user_func():

class foo {     function bar() { echo 'hi'; } }  $class = 'foo'; call_user_func(array($class, 'bar')); // prints hi 

However, this does not work when trying to access a static variable within the class:

class foo {     public static $bar = 'hi'; }  $class = "foo"; call_user_func(array($class, 'bar')); // nothing echo $foo::$bar; // invalid 

How do I get at this variable? Is it even possible? I have a bad feeling this is only available in PHP 5.3 going forward and I'm running PHP 5.2.6.

Answer 1

I think there is much better (more elegant) way then creating ReflectionClass instance. I also edited this code (and my answer) after few comments. I added example for protected variables (you can't of course access them from outside the class, so I made static getter and call it using variable pattern as well). You can use it in few different ways:

class Demo {     public static $foo = 42;     protected static $boo = 43;     public static function getProtected($name) {         return self::$$name;     } }  $var1 = 'foo'; $var2 = 'boo'; $class = 'Demo'; $func = 'getProtected'; var_dump(Demo::$$var1); var_dump($class::$foo); var_dump($class::$$var1); //var_dump(Demo::$$var2); // Fatal error: Cannot access protected property Demo::$boo var_dump(Demo::getProtected($var2)); var_dump($class::getProtected($var2)); var_dump($class::$func($var2)); 

Documentation is here:

http://php.net/manual/en/language.variables.variable.php