~/.emacs vs ~/.emacs.d/init.el

[Juanma Barranquero]

With the recent introduction of `user-emacs-directory', I've been
wondering... Could someone please clarify the relation between these
things:

--user                   (option for Emacs)
 init-file-user
 ~/.emacs.                (also _emacs, .emacs.el, _emacs.el)
 ~USER/.emacs             (is that possible on Windows?)
 ~/.emacs.d/init.el
 ~USER/.emacs.d/init.el   (is that possible at all?)

I've read the info nodes "Init File", "Find Init" and "Initial
Options"; I've also looked at the code. I'm still not sure whether

 emacs --user=another

should make ~another/.emacs.d/init.el possible, though the code
suggests that the answer is not (~/.emacs.d/ was hardcoded, and
`user-emacs-directory' does not change that), and I'm not sure why
(conceptually speaking).

            Juanma