How does such a construct work? Public function Name (Closure $ closure) {}

Closure are details of the closure implementation, i.e. anonymous functions.

 public function Name (Closure $closure){} 

The entry states that one argument must be passed to the method and this argument must be a closure. Those. in the simple case like this:

 $object->Name(function() { // какие-то действия }); 

A function is usually passed to a method with one purpose — for this method to be called somewhere. And you can call a function using different methods, for example:

 $closure(); // вот так call_user_func($closure); // или так 

Or transfer to some other function that takes the callback parameter. You can pass additional arguments to the function.

I note that it is rather strange to require Closure if you are going to use the methods of the Closure class. In general, to indicate the need to pass a function to a method, you must specify callable , which allows you to use any of the transmission options for this pseudotype .

The object of the Closure class is not intended to be instantiated using the new operator, since it has a private constructor. This is the "utility" class of PHP, which is used to create anonymous functions .

Design

 public function Name (Closure $closure){} 

tells us that this function takes an anonymous function as a parameter. Calling it in the code will look like this:

 $variable = Name(function(параметры){что-то делаем;}); 

This is how it uses in the laravel framework, but I don’t understand what they are trying to achieve with this.

 public function extend($abstract, Closure $closure) { $abstract = $this->normalize($abstract); if (isset($this->instances[$abstract])) { $this->instances[$abstract] = $closure($this->instances[$abstract], $this); $this->rebound($abstract); } else { $this->extenders[$abstract][] = $closure; } }