bug#41732: New ’package-with-emacs-next’ procedure

[zimoun]

Dear,

On Wed, 16 Sep 2020 at 16:51, zimoun <zimon.toutoune@gmail.com> wrote:

>>> I propose to provide 'package-with-emacs-next' for the people in the
>>> experimental mood. :-)  For example, the manifest looks like:
>>>
>>> (use-modules (guix build-system emacs)
>>>              (gnu packages emacs)
>>>              (gnu packages emacs-xyz))
>>>
>>> (packages->manifest
>>>  (cons emacs-next
>>>        (map
>>>         package-with-emacs-next
>>>         (list
>>>          emacs-lua-mode
>>>          emacs-magit))))
>>>
>>> Then the expert uses it with:
>>>
>>>    guix package -m manifest.scm
>>>
>>> Well, the attached patch does that.  And maybe, an entry to the
>>> Cookbook could be worth.

I withdraw the patch proposal since the patch set #43578 [1] fulfills
the request.  Now, for recompiling all the Emacs packages of one
manifest.scm file with the emacs-next package (changing the Emacs VM),
it is as easy as:

--8<---------------cut here---------------start------------->8---
guix build -m manifest.scm --with-input=emacs-minimal=emacs-next
--8<---------------cut here---------------end--------------->8---

Before closing, what do you think adding something in the manual or the
cookbook will be worth?  It could be useful when switching the Emacs
version –– for example the last 26 to 27.

[1] <http://issues.guix.gnu.org/issue/43578>

All the best,
simon