loris writes:

time to learn some Lisp, I suppose ...

Bob Chassell's An Introduction to Programming in Emacs Lisp is a good way to get started, if your primary objective is to extend Emacs, because Elisp has a lot of functions and concepts that are specific to text editing and would not be covered at all in a general Lisp book or tutorial. You can find the book online (though personally I like to support the FSF by buying hardcopies of their books).

One alternative is Writing GNU Emacs Extensions by Bob Glickstein, but this book is out of print, so you'll need to find a used copy.