anchor.diff: -{ pkgs, ... }:
  +{ pkgs, config, ... }:
  +
  +let
  +  unstable = import (builtins.fetchGit {
  +    name = "nixos-unstable-2019-04-29";
  +    url = https://github.com/nixos/nixpkgs/;
  +    rev = "496f9309480b22173e25885bc7c128c30fbd4da3"; # emacs 26.2
  +  }) {
  +    config = config.nixpkgs.config;
  +  };
  +in
   
   {
     nixpkgs.config.allowUnfree = true;
  
positive.code:     tig
      universal-ctags
      unrar
      unzip
      usbutils
      wget
  
negative.code:     cmus
      curl
      daemonize
      fd
      file
      fzf
  