Re: [PATCH] Unicode Lisp reader escapes

[Richard Stallman]

    >> Here's one idea: if the -*- line specifies `coding' and specifies
    >> the mode `emacs-lisp' then force unify-8859-on-decoding to nil
    >> for that file.

    Besides the work already mentioned, this would also require to turn
    unify-8859-on-decoding-mode into a buffer-local minor mode.

That is not the only possible implementation mechanism.  The commands
that read and write the buffer could change it temporarily and change
it back.

However, it seems like a really bad thing to have a minor mode
that CAN'T be buffer-local.  Why can't it be?  What is the difficulty?