Since I don't think anyone has mentioned it, I just thought I would pop in here and emphasize that this is not a feature of the "return" statement. A generic example might be:

$vacation_days = ($seniority > 5) ? 15 : 10;
[download]

which is equivalent to:

if ($seniority > 5) {
    $vacation_days = 15;
}
else {
    $vacation_days = 10;
}
[download]