anchor.diff:          autoload -U compinit && compinit
           autoload -U promptinit && promptinit
   
  +        bindkey -e
           setopt autocd
   
           export PROMPT='%B%(?..[%?] )%b> '
  
positive.code: { pkgs }:
  
  let
  
  
negative.code: 
          nixdarwin-rebuild () {
            case $1 in
              "build")  nix-build --no-out-link "<nixpkgs>" -A nixdarwin.toplevel ;;
              "repl")   nix-repl "$HOME/.nixpkgs/config.nix" ;;
              "shell")  nix-shell "<nixpkgs>" -p nixdarwin.toplevel --run "zsh -l" ;;
              "switch") nix-env -f "<nixpkgs>" -iA nixdarwin.toplevel && exec zsh -l ;;
              "")       return 1 ;;
            esac
          }
        '';
  