为什么在这个PHP代码的最后一个语句中有两个$ this？

Question

 parent::__construct();

    $this->displayName = $this->l('Responsive products featured');
    $this->description = $this->l('Displays featured products and categories in your homepage.');
    $this->

    include_once($this->local_path.'/classes/ResponsiveHomeFeaturedClass.php');

You will see that it is difficult to understand why the last statement uses two $this ?

Answer 1

(I'm not sure if you have an error in your pasted code, since include_once is a commonly used built-in function, but I suppose it could also be an instance function on an object...)

There's no reason why any one line of code can't reference $this twice, or as many times as it needs to. $this is just a reference to an object. So in this line of code:

$this->include_once($this->local_path.'/classes/ResponsiveHomeFeaturedClass.php');

It's just calling the include_once function and passing it a value, which includes the local_path value. This would accomplish the same thing:

$some_local_path = $this->local_path;
$this->include_once($some_local_path.'/classes/ResponsiveHomeFeaturedClass.php');

But it would be using an unnecessary temporary variable. include_once is just a function, and local_path is just a value. The latter can be used as a parameter for the former.