Iterate through all derivations in nixpkgs

[costrouc]

Is it possible with pythonix to view a derivation similar to "nix show-derivation ..."? I have tried nix.eval("with import {}; python3Packages.numpy") and ran into errors. Maybe this is not the correct way to view a derivation output? My end goal is that I want to create an adjacency matrix of runtime vs test vs build time python dependencies. But I have plans to use all the derivations to gather statistics. Right now the big limitation for me is how to extract this from nix.

[adisbladis]

I have implemented this in https://github.com/tweag/pynixutil.
You will still need to instantiate the derivation using the CLI (or pythonix!).