URI - getting segments into associative array with user-defined keys

[eluser]Jamie Rumbelow[/eluser]
There isn't anything like that currently, but it could be easily implemented. The only issue here is where would you put something like this? CodeIgniter's routing system is very simple, so it wouldn't make sense to put it in the routes.php config file. It would be messy if it was inline in the function code. It would be too cumbersome to put in the doccomment or somewhere else in the controller.

Where could it go?