如何調用PHP中存儲在Class屬性中的function

Question

嗨，我是 PHP 的新手，想知道您是否可以將 function 存儲在 Class 屬性中，然后稍后調用它。

class Route
{
  public $handler;
  //$handler is a reference to a function that I want to store and call later 
  function __construct($handler) 
  {
    $this->handler = $handler;
    //or maybe something like
    //$this->handler = fn () => $handler();

    //this works fine
    $handler();

    /*I get why this does not work since $handler is not a 
    method of this class but how would I store a function 
    and be able to call it later in a different context?*/
    $this->handler();
  }
}

我會怎么做這樣的事情？

function foo()
{
  echo "success";
}

$route = new Route('foo');
$route->$handler();

Answer 1

在調用存儲的可調用屬性時使用方括號：

class Route
{
  public $handler;

  public function __construct(callable $handler) {
    $this->handler = $handler;
  }
}

$handler = static fn() => var_dump('Works');
$obj = new Route($handler);

($obj->handler)();

然后

$ php test.php
string(5) "Works"

PS：我建議始終使用類型提示。

Answer 2

我希望下面的代碼有所幫助。

class Route
{
  public $handler;
  function __construct($handler)
  {
    $this->handler = $handler;
  }
}

function foo()
{
  echo "success";
}

$route = new Route('foo');

/* There is problem to call a function that is a class property. */
/* You may use a temporary variable. */
$function = $route->handler;
$function();