Hi Emacs support team,

I am an avid user of GNU Emacs and I love using Tex mode to write my
documents. However one of the features that I find lacking in Emacs is
*auto-complete*. By that I don't mean the common feature found in other IDE
for programmers but the following. Suppose I already typed up a formula

*\int_{\mathbb{R}} e^{2 \pi i x^2} dx = 1*

And after paragraph or so I want to repeat the same thing all over again
(and maybe modify *x* to *y*). Of course I can search+save region+yank but
that's too manual. What I wish to have is if I typed *\int* and then
invoked the *auto-complete *command, Emacs would move the point to the
previous instance of *\int* and allow me to mark a region around it. After
marking I could hit *Enter* and Emacs would copy the highlighted part and
put it to the partially completed *\int* below. I also want to be able to
cycle through previous instances of *\int* with the up and down arrow keys,
much like using *isearch*.

This could be also useful outside the scope of Tex mode. I realize this
sounds more like a minor mode rather than a macro.

Thanks,
Danny