Is there an R-extension to Emacs autocomplete-mode that can be used with ESS?
If the extension doesn\'t exist I\'d also appreciate any hints for writing one!
There is an ac-source for R here. I recall struggling with it and finally wrote my own which at that time was much faster, but buggy since I didn't manage to make prefix regexp work properly.
EDIT: the newest ESS (only svn currently) has out-of-the-box integration with auto-complete. I have added the instructions to the wiki.