[bug#47163] Using package transformations declaratively (was: [bug#47163] [PATCH] refresh: Add '--installed' option.)

[zimoun]

Hi,

On Tue, 16 Mar 2021 at 17:46, Xinglu Chen <public@yoctocell.xyz> wrote:
> On Tue, Mar 16 2021, Ludovic Courtès wrote:
>
> > You may also like the new ‘--with-latest’ package transformation
> > option.  :-)
>
> I really like package transformations but is there a way to use specify
> them with Guile so I can use them with `guix home`[1] or in manifests?

There is several ways to have package transformations at the manifest
level.  One is:

--8<---------------cut here---------------start------------->8---
(use-modules (guix transformations))

(define transform1
  (options->transformation
    '((with-c-toolchain . "hello=gcc-toolchain@8"))))

(packages->manifest
  (list (transform1 (specification->package "hello"))))
--8<---------------cut here---------------end--------------->8---


HTH,
simon