Re: The future of 'guix environment'

["Thompson, David" <dthompson2@worcester.edu>]

On Thu, Aug 31, 2017 at 3:18 AM, Jan Nieuwenhuizen <janneke@gnu.org> wrote:
> Thompson, David writes:
>
>> Hi all, been awhile!
>
> Hi David!
>
> Great suggestions all!  I use guix environment heavily and like it a
> lot.

Thanks!

>> 4) Make 'guix environment' with no other args operate like 'guix
>> environment --cache --load=guix.scm'.  'guix.scm' is a placeholder
>> name for whatever we decide the conventional name for an environment
>> config should be.
>
> Wouldn't that be
>
>     guix environment --cache --dependencies --load=guix.scm

No, because guix.scm would no longer evaluate to a package object, but
an environment object.  Flags like --dependencies are for environments
defined on the fly at the command line.  I haven't yet decided if
--load should be mutually exclusive from all those other things, but I
think that should probably be the case.  Perhaps introducing
subcommands is the best thing UX-wise.  'guix environment load
guix.scm', 'guix environment shell direnv --dependencies ruby', and
'guix environment' would be a shorthand for 'guix environment load'.
This will take some fiddling to see.  I'm going to get the core
features implemented first, then work on the UX.

> I have been using an ugly hack to switch profiles (or environments; look
> at $GUIX_ENVIRONMENT) in Emacs, see attached.  As discussed briefly on
> irc yesterday are various ways this could go: use emacs-direnv, read the
> manifest file in elisp, use guix repl to read it..etc

I took a look at emacs-direnv and did not like it because it's not
fully implemented in elisp. You also need the direnv tool itself,
which is written in Go. No thanks!  I think the integration should
happen with emacs-guix, which could use the Guile REPL to read the
profile manifest, and send an sexp back to Emacs with key/value pairs
for the values of all environment variables.  From there it's easy to
use setenv and tweak exec-path in the case of $PATH.  Alex Kost would
know a lot better than I about how to get this done.

- Dave