Laravel IOC understand.

simple.php

class Foo
{
    private $bar;
    private $baz;

    public function __construct(Bar $bar, Baz $baz)
    {
        $this->bar = $bar;
        $this->baz = $baz;
    }
}
class Bar{}
class Baz{}
class Mock{}
App::instance('Foo', new Mock);

App::bind('Foo', function() {
    return new Foo(new Bar, new Baz);
});

get('foo', function() {
    dd(App::make('Foo'));
});