php7.0新特性简介

declare(strict_types=1);
function aa(int $a){
    return $a;
}
echo aa('5');//会报错。

declare(strict_types=0);//默认就是强制
function aa(int $a){
    return $a;
}
echo aa('5');//输出5。

 function aa(int $a) : array{
    return [$a];
}

// if it does not exist.
$username = $_GET['user'] ?? 'nobody';
// This is equivalent to:
$username = isset($_GET['user']) ? $_GET['user'] : 'nobody';

echo $a <=> $b;//当$a>$b 输出1  当$a < $b 输出-1    当$a == $b 输出0

defined('ANIMALS') or define('ANIMALS', [
    'dog',
    'cat',
    'bird'
]);
var_dump(ANIMALS);//输出array(3) { [0]=> string(3) "dog" [1]=> string(3) "cat" [2]=> string(4) "bird" }

$a = new class{
public function echo(){
return $this;
}
public function className(){
return __CLASS__;
}
};
var_dump($a->className());
//string(67)"class@anonymousF:\WWW\test\test02.php001A0165"

class A{private $x = 1;}


$getx = function(){
return $this -> x;
};


echo $getx->call(new A); //输出1