nixpkgs-python-importer

What

An importlib hack that allows from nixpkgs.pythonpackagename import modulename.

Examples:

from nixpkgs.scipy import scipy
import nixpkgs.scipy.scipy
from nixpkgs.matplotlib.matplotlib import pyplot as plt
import nixpkgs.matplotlib.matplotlib.pyplot as plt
from nixpkgs.pillow.PIL import Image

Why

I used to be a researcher who used python and xonsh interactively a lot. While I appreciate the purity of Nix, sometimes I really want to violate it and pull in some dependency into my shell right now, without tearing my session down, editing and rebuilding an environment, and then recreating my session from history.

A convenient way of spawning a xonsh instance with an extra dependency soothes the nerves a bit, but doesn't really free me from the recreation part.

I started writing a xonsh macro that ended up being a generic Python solution with a pleasingly nice syntax. I mean, from nixpkgs.scipy import scipy. Ain't that nice?

How

importlib magic

Try

The quickest way to try it would be (on a recent NixOS):

nix run -f '(import <nixpkgs> {}).python3.withPackages(ps:[ps.nixpkgs])' -c python

then try from nixpkgs.pbr import pbr (or any other package).

If that doesn't work, you may also try your luck with unstable nixpkgs:

nix run -f channel:nixos-unstable '(import <nixpkgs> {}).python3.withPackages(ps:[ps.nixpkgs])' -c python