maybe hippie-expand? otherwise, you can write your own code to search the buffer for entries, and use them as the collection for completing-read.

John

-----------------------------------
Professor John Kitchin 
Doherty Hall A207F
Department of Chemical Engineering
Carnegie Mellon University
Pittsburgh, PA 15213
412-268-7803

On Sat, Aug 1, 2015 at 8:08 PM, Vikas Rawal <vikaslists@agrarianresearch.org> wrote:
I am adding index entries in an org document, to be used with makeidx latex package. While the usual \index commands are working without any problem, I was wondering if anyone knows of an existing emacs utility that would add an autocomplete kind of facility (on the basis of previous entries) while making new entries.

Sorry, this is not strictly about orgmode but about emacs. Please excuse me for that.

Vikas