expressions that cause an assertion failure (like `assert system ==
"i686-linux"'). This allows all-packages.nix in Nixpkgs to be used
on all platforms, even if some Nix expressions don't work on all
platforms.
Not sure if this is a good idea; it's a bit hacky. In particular,
due to laziness some derivations might appear in `nix-env -qa' but
disappear in `nix-env -qas' or `nix-env -i'.
Commit 5000!
derivation(s) we're interested, e.g.,
$ nix-instantiate ./all-packages.nix --attr xlibs.libX11
List elements can also be selected:
$ nix-instantiate ./build-for-release.nix --attr 0.subversion
This allows a non-ambiguous specification of a derivation. Of
course, this should also be added to nix-env and nix-build.
