$result = Auth::attempt(Input::only('email', 'password'));

/* @var $app IlluminateFoundationApplication */
$app = App::make("app");

/* @var $auth IlluminateAuthAuthManager */
$auth = $app->get("auth");

use IlluminateAuthGuard as Auth;

public $auth;

public function __construct(Auth $auth)
{
    $this->auth = $auth;
}

public function doSomething()
{
    $this->auth->attempt(Input::only('email', 'password'));
}

public function __call($method, $parameters)
{
    return call_user_func_array(array($this->driver(), $method), $parameters);
}

/* @var $manager IlluminateAuthAuthManager */
$manager = $app->get("auth");

/* @var $guard IlluminateAuthGuard */
$guard = $manager->driver();