PHP5.6新特性例子举证

const ONE = 1;
const TWO = ONE * 2;

class C {
    const THREE = TWO + 1;
    const ONE_THIRD = ONE / self::THREE;
    const SENTENCE = 'The value of '.THREE.' is 3';

    public function f($a = ONE + self::THREE) {
        return $a;
    }
}

echo (new C)->f()."＼n";
echo C::SENTENCE;

function f($req, $opt = null, ...$params) {
    // $params is an array containing the remaining arguments.
    printf('$req: %d; $opt: %d; number of params: %d'."＼n",
           $req, $opt, count($params));
}

f(1);
f(1, 2);
f(1, 2, 3);
f(1, 2, 3, 4);
f(1, 2, 3, 4, 5);
上面代码输出：

$req: 1; $opt: 0; number of params: 0
$req: 1; $opt: 2; number of params: 0
$req: 1; $opt: 2; number of params: 1
$req: 1; $opt: 2; number of params: 2
$req: 1; $opt: 2; number of params: 3

function add($a, $b, $c) {
    return $a + $b + $c;
}

$operators = [2, 3];
echo add(1, ...$operators);

namespace Name＼Space {
    const FOO = 42;
    function f() { echo __FUNCTION__."＼n"; }
}

namespace {
    use const Name＼Space＼FOO;
    use function Name＼Space＼f;

    echo FOO."＼n";
    f();
}
上面代码输出：

42
Name＼Space＼f
phpdbg

$a = gmp_init(42);
$b = gmp_init(17);
 
// Pre-5.6 code:
var_dump(gmp_add($a, $b));
var_dump(gmp_add($a, 17));
var_dump(gmp_add(42, $b));

// New code:
var_dump($a + $b);
var_dump($a + 17);
var_dump(42 + $b);