Where is documentation for ($this pointer)?

An example.

class classname
{
public $attribute;
function operation($param)
{
$this->attribute = $param
echo $this->attribute;
}
}

I am having trouble understanding the $this pointer in the book I am reading. I cannot find it in the documentation on php.net.

Why is this?
How can I learn this?
Thanks.

 

Operation is a custom function that takes one parameter - $param. Inside that function $this->attribute equals to $param and later $this->attribute (which equals to $param) is echoed out.

 

Thanks for your reply.

Let me try to clear up any confusion.

The example above was just to illustrate the $this pointer.

There are more complicated examples in the book I am reading that I am having trouble understanding.

My question is- where can I find documentation of the $this pointer that will explain its purpose and elaborate on its use?

Thanks.

 

Check out http://www.phpfreaks.com/forums/index.php/topic,95867.0.html and http://www.php.net/manual/en/language.operators.php.

 

In short when you declare a class you don't know exactly the name of object of this class in future.
For example for your code I can write:

$first = new classname();

PHP:

or

$anyname = new classname();

PHP:

So to refer to certain object of declared class in future $this is used. It is always an object of this class.
So for my examples:
Inside $first $this will refer to $first and inside $anyname $this refers to $anyname;

 

Thanks.

I thought ($this) was a keyword and would have whole a page of discussion devoted to it. I did not find it in the list of keywords on php.net.

I looked at your links. I did not find as of yet ($this) specifically discussed as a topic by itself, but I did learn that (->) is called an object operator. I have been wondering what that was called for some time.

 

It's explained on this page
http://www.php.net/manual/en/language.oop5.basic.php

 

Thanks AsHinE.

Maybe the concept ($this) is so simple I am having trouble rapping my brain around it.

 

Thanks JAY6390.

I will study that page you sent.