The -> is the symbol(s) used to refer to data within an object class.
In your example, $ab is an object of some class and $cd is a property within that class.
Here's an example:
<?php
class Customer
{
var $cd = "Compact Disc";
}
$ab = new Customer();
print $ab->$cd . "<br>\n";
Prints "Compact Disc<br>\n"
$ab->$cd = "Kompakt Disk";
print $ab->$cd . "<br>\n":
Prints "Kompakt Disk<br>\n"
?>
Does this help?
-Rich
