$var = 0;

// switch 文が falseと評価されてしまう
switch($var) {
	case ($var == 0):
		echo "0!";
		break;
	default:
		break;
}

$var = 0;

// switch 文を強制的にtrueで評価
switch(true) {
	case ($var == 0):
		echo "0!";
		break;
	default:
		break;
}

$test = 'aaa';
switch (true) {
	case ($test > 10):
		echo "10!";
		break;
	case is_numeric($test):
		echo "digit!";
		break;
	case is_float($test):
		echo "float!";
		break;
	case is_aaa($test):
		echo "aaa!";
		break;
	default:
		break;
}

function is_aaa($str)
{
	return ($str == 'aaa');
}