{ pkgs ? import <nixpkgs> {}
, compiler ? "ghc864"
}:

let src = pkgs.nix-gitignore.gitignoreSource [] ./.;

    # Any overrides we require to the specified haskell package set
    haskellPackages = with pkgs.haskell.lib;
      pkgs.haskell.packages.${compiler}.override {
      overrides = self: super: {
      };
    };

    # Any packages to appear in the environment provisioned by nix-shell
    extraEnvPackages = with haskellPackages; [
    ];

    # Generate a haskell derivation using the cabal2nix tool on `package.yaml`
    drv = haskellPackages.callCabal2nix "" src {};

    # Insert the extra environment packages into the environment generated by
    # cabal2nix
    envWithExtras = pkgs.lib.overrideDerivation drv.env (attrs: {
      buildInputs = attrs.buildInputs ++ extraEnvPackages;
    });

in
  drv // { env = envWithExtras; }