Modify CodeIgniter to Support Hyphens in URL Request Segment

MY_Router.php

<?php
/*
|
| Put this file (MY_Router.php) inside /application/core (CI2)
| Remember that this will effect all segments, not only module, controller and method.
| 
| Alternative to this extend is to add each segment to application/config/routes.php
| $route['this-is-a-module-or-controler'] = 'this_is_a_module_or_controller';
| 
| As you can see the extend method would be easier to use. You can choose to make
| the function also to handle only the first two or three segments so that the other
| segments are not affected with the '_' replacement.
|
*/
class MY_Router extends CI_Router
{
    function _set_request($segments = array()) {
        parent::_set_request(str_replace('-', '_', $segments));
    }
}