On Mon, Nov 17 2014, Jorgen Schaefer wrote:

> Some initial patch attached.

I'm proposing an alternative implementation.  This version uses EIOIO
which, I think, makes it more flexible.  Proof-of-concept-quality
backends for elisp and etags are included.  The UI is lifted from SLIME
(with some simplifications).  To try it out, load xref.el and then M-x
xref-minor-mode to turn it on.  It's not fully polished but good enough
to show the main ideas.

Also available at: https://github.com/ellerh/xref/blob/master/xref.el