为什么php中的代码行中会有多个对象运算符？

Question

I'm a n00b tying to get my head around the operator syntax. I understand it's called the object operator and I can see how it's used ( Where do we use the object operator "->" in PHP? ) by itself.

I'm trying to learn what the purpose is when they are strung together like in this snippet (eg "switch($this->request->param('id')):

here's a snippet of code from a site using Kohana:

public function action_list()
{
    $connections = ORM::factory('Connection')
        ->with('property')
        ->with('inviter');
    switch ($this->request->param('id')) {
    // more code...
        }
    }

Answer 1

It's called "method chaining". It allows you to apply more then one method, and thus do more then one thing, in one call. It's sort of the OOP equivalent of nesting functions.

Answer 2

It's often referred to as chaining. When a method returns an object, you can call another method on that returned object. Consider something like this:

class A {
    public $numbers = 0;
    public function addNumber($num) {
        $this->numbers += $num;
        return $this;
    }

}

$a = new A();
$a->addNumber(1)->addNumber(2);

addNumber is returning an instance of itself, so you can call addNumber repeatedly.

It's often the case that a method will return an instance of another object, but the same principles apply.