{ pkgs ? (import <nixpkgs> {})
}:

pkgs.stdenv.mkDerivation rec {
  name = "substitution-env";
  buildInputs = [ (pkgs.haskellPackages.ghcWithPackages (p:
                    with p; [ case-insensitive containers
                            ]))
                ];
  shellHook = ''
    export PROMPT_INFO="${name}"
  '';
}