Re: Recursive substitute-keyword-arguments / setting default on build system

[Hilton Chain <hako@ultrarare.space>]

Hi Nils,

On Tue, 26 Sep 2023 19:08:06 +0800,
nils@landt.email wrote:
>
> Hello,
>
> I use a slightly customized emacs package, and want to use it as the package that is used in emacs-build-system for the emacs plugins I'm using.
> The default emacs gets garbage collected and takes quite a while to reinstall, I would like to avoid that. Also, it seems cleaner to build the plugins with the exact version that they will be used with.
>
> Here's what I have:
>
> (define emacs-package
>   ((const
>      ((options->transformation
>         '((with-configure-flag . "emacs=--program-transform-name='s/^ctags$/ctags.emacs/'")))
>       emacs))))
>
> (define (set-build-system-emacs plugin-package)
>   (package
>     (inherit plugin-package)
>     (arguments
>       (substitute-keyword-arguments (package-arguments plugin-package)
>                                     ((#:emacs emacs) `,emacs-package)))))
>
> (map set-build-system-emacs package-list)
>
> From what I can tell this does work for the packages in package-list, but not for any inputs to those packages. That makes total sense to me, but I don't know how to solve it.
> Any pointers? Or is it possible to set the default package for a build system, removing the need for this mapping altogether?

`package-input-rewriting' (documented in [1]) can be used for the
purpose:

--8<---------------cut here---------------start------------->8---
(map (package-input-rewriting
      `((,emacs-minimal . ,emacs-package)
        (,emacs . ,emacs-package)))
     package-list)
--8<---------------cut here---------------end--------------->8---

Thanks
---
[1]: https://guix.gnu.org/en/manual/devel/en/html_node/Defining-Package-Variants.html