[PATCH 0/2] emacs: Add "M-x guix-package-from-file.

[Alex Kost]

This is to add an Emacs companion of "guix build --file" and
"guix package --install-from-file".

Patches:

[PATCH 1/2] emacs: main: Remove top-level package tables.

  This patch finally rewrites that part of code in a functional style.
  Many thanks to Ludovic for past comments on using 'delay' and vhashes.

[PATCH 2/2] emacs: Add 'guix-package-from-file' command.

  And this patch partially breaks the functional style.  A new package
  (from an arbitrary file) must be registered in a table of packages, so
  that it can be addressed later (for example, if a user would want to
  install it).  So this is done using not very functional 'set!' in
  'register-package' procedure (at least it sets a local variable).  Is
  there a better way to write this?