PHP匿名函数使用技巧与场景解析

$func = function($param) {
    return "Hello, $param";
};
echo $func("World"); // 输出：Hello, World

$greet = fn($name) => "Hi, $name";
echo $greet("Alice"); // 输出：Hi, Alice

$numbers = [1, 2, 3, 4, 5];
$squared = array_map(function($n) {
    return $n * $n;
}, $numbers);
// 结果：[1, 4, 9, 16, 25]

$dispatcher->on('user.login', function($user) {
    echo "用户 {$user->name} 已登录";
});

$logger = function($msg) {
    file_put_contents('log.txt', date('Y-m-d H:i:s') . " - $msg\n", FILE_APPEND);
};
$logger("系统启动");

$factor = 2;
$double = function($n) use ($factor) {
    return $n * $factor;
};
echo $double(5); // 输出：10

class User {
    private $name = "Bob";
}
$getName = function() {
return $this->name;
};
$user = new User();
$boundMethod = $getName->bindTo($user, User::class);
echo $boundMethod(); // 输出：Bob