CodeIgniter avoid redundancy of Admin app

Question

My CodeIgniter setup follows the usual scheme -- a user app, and a second app called 'admin' that is one directory-level down. As I understand things, it's presumed the end-user will want his/her own interface, probably one with less public access; so you have 'admin'.

But Model and Library functions will often be the same for both. That means maintaining duplicate files so both apps are provided for -- with all the tedium and risk inherent in redundant code.

How do you consolidate your functions?

Answer 1

Having researched more, it looks like this is roughly a duplicate of: http://stackoverflow.com/questions/2188364/multiple-applications-with-codeigniter-from-same-framework-directory

... which references this: http://codeigniter.com/forums/viewthread/136321/

... and also relates to this: http://codeigniter.com/user_guide/general/managing_apps.html