[php] switch che non capisco

[V1RuZ]

con switch innestati mi sembra + leggibile:

isset($_GET['cat']) ? $cat = $_GET['cat'] : $cat = ''; 
isset($_GET['sub']) ? $sub = $_GET['sub'] : $sub = ''; 

switch ($cat) { 
case "a": 
$macro = "Corsi Fashion Fondamentali"; 
switch($sub){
    case "1":
        $micro = "Fashion Make Up";
        break;
    case "2":
        $micro = "Fashion Hair";
        break;
    default:
        $micro = "";
}
break; 
case "b": 
switch($sub){
    case "1":
        $micro = "Fashion Make Up(2)";
        break;
    case "2":
        $micro = "Fashion Hair-Styling";
        break;
    default:
        $micro = "";
}
break; 
} 

echo $macro."-".$micro;