Nix is really cool, and gets even cooler with NixOS.
To answer your questions: On the second run all packages are saved in the local store, so it's super fast. Language specific dependencies are treated like all other Nix packages, so Python dependencies can depend on Node, etc.
To answer your questions: On the second run all packages are saved in the local store, so it's super fast. Language specific dependencies are treated like all other Nix packages, so Python dependencies can depend on Node, etc.