Every language has it's equivalent of virtualenv, and that's the problem: it only works for that language's tools and libraries. I don't use Nix, but I do hack

Every language has it's equivalent of virtualenv, and that's the problem: it only works for that language's tools and libraries. I don't use Nix, but I do hack on an alternative called GNU Guix sometimes, and I wrote a tool called 'guix environment' which is similar to virtualenv but applicable to any software. Having a generalized solution is much better than one virtualenv tool and package manager per programming language. In Nix the equivalent tool is called nix-shell.