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I was wondering - can you redefine the special variable $this when in a method of a class. It turns out that yes, you can.

Consider this class:
< ?php
class Some {
function Some(){}
function another(){
$this = 5;
var_dump($this);
}
}
?>
If you create an object and call the another() method, it will redefine $this and will make it an integer as opposed to an object.
< ?php
$s = new Some();
$s->another();
?>
This gives

int(5)


If you dump the instance after the method call it will still return 5, so it's not just a temporary re-definition.

Similarly, you can even destroy an object from within a method of the class, like
< ?php
class Some {
function Some(){}
function another(){
$this = null;
}
}

$s = new Some();
$s->another();
var_dump($s);
?>
This will output NULL.

This entry was posted on Monday, March 28th, 2005 and is filed under PHP certification. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.