Re: Parameterized packages

[zimoun]

On Mon, 20 Jan 2020 at 10:08, Pierre Neidhardt <address@hidden> wrote:
>
> Ludovic Courtès <address@hidden> writes:
>
> > I agree.  ‘package-input-rewriting’ gives us almost what you want, with
> > the limitation that implicit inputs are ignored (which is a good thing
> > sometimes, and a problem in cases where you want to experiment with
> > toolchains, as you write).
> >
> > What we’d need is a variant of ‘package-input-rewriting’ that somehow
> > walks through implicit dependencies.  It could do that by changing the
> > build system, I guess.
>
> To clarify, this does not cover the extent of what "parameters" could
> do, since parameters are not just about input rewriting.

As we discussed here [1]:
<<
> Should we touch implicit inputs, we would have to parse all the
> references and not just the explicit inputs like --with-input does.

My mind is not clear at all.

What is the final aim to have parametrized packages?
What does it mean "parametrized"?
Does it mean extend the transformation options as Ludo described [2].
Does it mean more?
>>

Could you define what do you mean by "parameters"?
Sorry to be slow but I am not clear about what we are talking about
precisely. :-)

1. Because the initial Ludo's message was about glic-locale which is
somehow an input.
2. The thread spoke also about flags à la Gentoo USE flags.
3. Other messages were about set X or Wayland or no-X for this or that package.
4. Another were about change the toolchain of the build systems.
etc.

All are "parameters". :-)

The solution of 1. and 4. seems to be able to re-write all the implicit inputs.

The solution of 2. and 3. seems to write, as Ludo mentioned:

--8<---------------cut here---------------start------------->8---
(define (make-me-a-package option1 option2)
    (package
      …))
--8<---------------cut here---------------end--------------->8---


Well, could you clarify what do you have in mind about "parameters"?
Just to stay on the wavelength and keep focus. :-)


[1] https://lists.gnu.org/archive/html/guix-devel/2020-01/msg00274.html




Cheers,
simon