Am Donnerstag, 10. Januar 2013 schrieb Ludovic Courtès:
> Nix provides other options that extend this model to something closer to
> what you say, namely ‘gc-keep-outputs’ (see
> <http://hydra.nixos.org/build/3676991/download/1/nix/manual.html>.)
> 
> I guess we should add a guix-daemon option for that.

If I understand the manual correctly, this is not exactly what I meant. I 
thought of simply keeping all packages that are needed to build a simple 
project, such as "hello". Or maybe just keeping gcc, as it takes really 
very long to build. But indeed, this is less critical once binary downloads 
from a build farm are possible.

Another option would be something close to debian's "apt-get autoclean": 
Keep all the packages that are still available in the sense that they would 
be built by calls to "guix-build", looping over the output of "guix-package 
--list-available".

Andreas