Recently I needed to use cabal's
data-files feature, and the only really useful reference (the Cabal manual seems to be lacking) I could find was a post from 2008 describing how to use a custom
Paths module in a package.
However, it seems that you don't need to create your own separate
Paths module any more – Cabal will provide the
Paths module when you use any
cabal command, so you can
import Paths_whatever and it'll handle it automatically for you.