Emacs use-package: Guix backend?

[Ricardo Wurmus <rekado@elephly.net>]

Hi Guix,

I recently moved all my Emacs packages to a separate profile, which is
controlled by a manifest that’s generated from my init.org configuration
file.  I like this, because I can separately upgrade packages from my
main profile and keep my Emacs configuration self-contained.

What still annoys me, though, is that package installation is separate
from configuration.  I don’t really want to be forced to update the
manifest at the top of my init.org before I can configure the package
somewhere at the bottom of the init.org.

The “use-package” macro was designed to allow for both installation and
configuration in the same place.  By default it uses package.el to
install packages when they aren’t available yet.  I’d like to use
“use-package”, but I’d like it to install packages with Guix and also
install to a separate Guix profile, preferably via a manifest.

Package managers are supposed to override “use-package-ensure-function”
and/or “use-package-pre-ensure-function” to use something other than
package.el.

Before I embark on this journey, do any of you have travel reports to
share?  Do you think this is worth doing?  If so, where could we add
this feature so that all Guix users benefit from it?  Emacs-Guix?

-- 
Ricardo