indirect function call

Hi,
We are having a little problem with indirect function calls as being
discussed on the list for a while... The below thingie does not work,
does anybody have any idea to make it run?

regards,
-bd

<?php

class bdd
{
        var $bdd_var;
        function bdd_function($input)
        {
                echo "This is bdd_function speaking and the input is :
$input";
        }
}

$foo = new bdd;
$bar = $foo->bdd_function;
$bar("foo bar !");
?>