configuration-snippet.nix

{ config, lib, ... }:

{
  nixpkgs.config.packageOverrides = super: let self = super.pkgs; in
    {
      myHaskellEnv = self.haskellPackages.ghcWithHoogle
                       (haskellPackages: with HaskellPackages; [
                         # libraries
                         arrows async cgi criterion
                         # tools
                         cabal-install haskintex
                        ]);
    };
    
  environment.systemPackages = with pkgs; [
    myHaskellEnv
  ];
}