What I normally do in those situations is to specify the parameters as an array instead. Have a look at the following example (untested):
'something'));
function test($options = array())
{
$default_options = array('t1' => 'test1', 't2' => 'test2', 't3' => 'test3');
$options = array_merge($default_options, $options);
echo $options['t1'] . ', ' . $options['t2'] . ', ' . $options['t3'];
}
?>