Periods not allowed in CodeIgniter URI?

Question

So after reading this question on API versioning, I decided to prefix all my routes with a version number:

http://localhost/api/1.0/user/login

Answer 1

The problem is on line 468 of system/core/Router.php. Change set_directory from this:

$this->directory = str_replace(array('/', '.'), '', $dir).'/';

To this:

$this->directory = str_replace(array('/'), '', $dir).'/';

Anyone have a guess or gander as to why the Router removes periods from directory names?