get parent folder paths with php

Question

I am working on my first MVC framework, and want to define 4 constants for BASE_PATH, APP_PATH, LIB_PATH & PUBLIC_PATH. My file structure looks like this:

/
/app
    /controllers
    /models
    /views
/config
/db
/lib
/public_html
    /css
    /js
    /img

My index.php file is located in the public_html directory. And currently has the following code:

error_reporting(E_ALL);
define('BASE_PATH',dirname(realpath(__FILE__)) . "/../");
define('APP_PATH',dirname(realpath(__FILE__)) . "/../app/");
define('LIB_PATH',dirname(realpath(__FILE__)) . "/../lib/");
define('PUBLIC_PATH',dirname(realpath(__FILE__)) . "/");

require LIB_PATH . 'core.php';

This works, but I feel like there must be a better way of doing it without all of the "..". Any suggestions or is this the best way of going about it? Let me know. Thank you!

---

ANSWER

Thank you to @fireeyedboy and @KingCrunch, I have come up with the solution I was looking for. This is my final code:

define('PUBLIC_PATH', dirname(__FILE__) . "/");
define('BASE_PATH', dirname(PUBLIC_PATH) . "/");
define('APP_PATH', BASE_PATH . "app/");
define('LIB_PATH', BASE_PATH . "lib/");

Answer 1

How about this:

define('PUBLIC_PATH',dirname(realpath(__FILE__)) . "/");
define('BASE_PATH',dirname(PUBLIC_PATH));
define('APP_PATH',BASE_PATH . "/app/");
define('LIB_PATH',BASE_PATH . "/lib/");

In other words use dirname() again. And re-order defining the constants to make direct use of them. Not sure it helps readability though.

Answer 2

First:

realpath(__FILE__)

is just useless

However, there no "real" better way, because ../ is not "dirty". The only other solution, that comes in my mind

dirname(dirname(__FILE__))

.. is the way a filesystem (its not invented by php ;)) defines its parent directory, just as well . defines the current directory.