[Nix-dev] Nix expressions for channel nixpkgs-unstable

[Konrad Hinsen]

I am starting to explore the nixpkgs collection and I wonder if there is a
way to see the Nix expressions that correspond to the current state of the
channel nixpkgs-unstable, in order to understand exactly what's going on
when packages are installed.

My first idea was to use the Subversion repository for nixpkgs, but it
seems that the channel has only a subset of those packages, and not
necessarily uses the same versions. For example, when I install
python-numpy from nixpkgs-unstable I get Python 2.6, whereas
all-packages.nix in the repository defines python=python27.

Alternatively, is there a simple way to install packages using a
source code version of nixpkgs, rather than subscribing to the
channel?

Thanks in advance,
  Konrad.