Set/replace $this variable in PHP - php

Question

Is there a way to set or modify the variable $this in PHP? In my case, I need to call an anonymous function where $this refers to a class that is not necessarily the class that made ​​the call.
Pseudo-example:
function test() {
echo $this->name;
}
$user = new stdclass;
$user->name = "John Doe";
call_user_func(array($user, "test"));
Note: this will generate an error, because, in fact, the function expects an array containing an object and a method that exists in this object, and not any method of global scope.

Answer 1

Why not try setting the function definition to accept an object as a parameter? For example:
function test($object) {
if (isset($object->name)) // Make sure that the name property you want to reference exists for the class definition of the object you're passing in.
echo $object->name;
}
}
$user = new stdclass;
$user->name = "John Doe";
test($user); // Simply pass the object into the function.
The variable $this, when used in a class definition, refers to the object instance of the class. Outside of a class definition (or in a static method definition), variable $this has no special meaning. When you attempt to use $this outside of the OOP pattern, it loses meaning and call_user_func(), which relies on the OOP pattern, will not work in the way that you've attempted.
If you're using functions in a non-OOP way (like global functions), the function is not tied to any class/object and should be written in a non-OOP way (passing in data or otherwise using globals).

Answer 2

You can use the bind method on a closure object to change the meaning of this in a particular context. Note this functionality became available in PHP 5.4.
Official Description
Duplicates a closure with a specific bound object and class scope
class TestClass {
protected $var1 = "World";
}
$a = new TestClass();
$func = function($a){ echo $a." ".$this->var1; };
$boundFunction = Closure::bind($func, $a, 'TestClass');
$boundFunction("Hello");
// outputs Hello World
An alternative to this syntax it to use the bindTo method of an instance of a closure (anonymous function)
class TestClass {
protected $var1 = "World";
}
$a = new TestClass();
$func = function($a){ echo $a." ".$this->var1; };
$boundFunction = $func->bindTo($a, $a);
$boundFunction("Hello");
// outputs Hello World
In your example the relevant code would be
$test = function() {
echo $this->name;
};
$user = new stdclass;
$user->name = "John Doe";
$bound = $test->bindTo($user, $user);
call_user_func($bound);