Re: Guile 3 migration plan

[zimoun]

Hi,

On Thu, 16 Jan 2020 at 11:08, Ludovic Courtès <address@hidden> wrote:

>   1. We must first migrate packages.  I propose to rename “guile-next”
>      to “guile” today, such that “guix install guile” will now install
>      Guile 3 (no mass rebuild involved: the “default” Guile remains
>      2.2.)
>
>      The downside is that if you run “guix install guile guile-json”,
>      you’ll get Guile 3 with Guile-JSON for 2.2; instead, you have to
>      explicitly select “guile3.0-json”.
>
>      I propose renaming all the “guile3.0-” packages to “guile-”, and
>      all the “guile-” packages to “guile2.2-” as a second step, which
>      will address this issue.  This could be done within a few days or
>      weeks.

It is not related to only the migration to Guile 3 but I feel
something is lacking about switching between the underlying "compiler"
used by the build system.

I agree that it is combinatorial and so not possible to support all.
However, I would like to easily switch between Guile 2 and Guile 3,
between R 3.6 and R 3.5, between GCC 8 and GCC 9, etc. building the
same definition of the package using another "builder" than the
default one.

For example, today there is the 'package-with-python2' function to use
Python 2 instead of Python 3 for the same python-package. There is
also 'package-with-explicit-inputs' to help to switch. Or the
'inherit' mechanism. But it does not appear to me easy to finely tune
the building toolchain.

Well, does it make sense to expose "parameters" as the version of the
compiler/interpreter of the build systems?


All the best,
simon