Its used in conjuction with Classes, the object orientated features that the PHP language supports. Here is a very basic layout:
// start the class (object template)
class TEST {
var $val
function test($in) {
$this->val = $in;
}
function change($mult) {
$this->val = $this->val * $multi;
}
function result() {
return $this->val;
}
}
// then call the class
$ob = new test("3"); // create object and pass 3 into test method
$ob->change("3"); // pass 3 into the change method
echo $ob->result(); // should echo out 9 (3*3)
Not tested the above, but hopefully it should give you an idea of what -> represents.