Support find-file-at-point or something like it, to open a file referenced by your nix expression

[grahamc]

It would be super neato to support the following use cases:

(1) relative paths, pretty easy since it is relative to the current file!

{
  imports = [
    ./macs/nodes/mac5.nix
  ];
}

having the cursor at the beginning of ./macs/nodes/mac5.nix, being able to do C-c C-o or something to open the file.

(2) paths based on NIX_PATH

a bit trickier, but would be pretty neat:

{ pkgs ? import <nixpkgs> }:
null

being on <nixpkgs> and have it open default.nix of the NIX_PATH's nixpkgs. This can be done with nix-instantiate:

grahamc@Morbo> nix-instantiate  --eval -E '<nixpkgs>'
/nix/var/nix/profiles/per-user/root/channels/nixos

of course, this should also support sub-files using the same method:

grahamc@Morbo> nix-instantiate  --eval -E '<nixpkgs/nixos/lib/make-channel.nix>'
/nix/var/nix/profiles/per-user/root/channels/nixos/nixos/lib/make-channel.nix

Ideally version 2 would also support direnv altering the NIX_PATH.