To "move on from Emacs" is not an idea that makes sense to everyone...
Let me talk a bit about my own extreme case :-). I started using Emacs
in 1994, my .emacs file has about 12000 lines (because I usually leave
old functions there instead of removing them), and practically all the
files that I have created in all these years are full of elisp
one-liners that I can execute with eval-last-sexp... and my
"customizations" are mostly functions that I can call from these
one-liners. Also, Emacs has a huge community (see the Emacs Wiki) and
lots of people there use Emacs in other funny ways, and have written
lots of code for that over the years.
If there is any interest I can write some simple Emacs primitives - see
for creating and destroying a lua_State from elisp, and for eval'ing a
string in it... My C skills have rusted down, though, and the way to
plug that into an Emacs build tree won't be the prettiest - someone
else would have to volunteer to clean that up. So? :-)
Cheers,
Eduardo Ochs