shell.nix

{ nixpkgs ? import <nixpkgs> { overlays = [ (import ./overlay.nix) ]; },
  compiler ? "default",
  withHoogle ? true,
}:

let

  inherit (nixpkgs) pkgs;

  f = { mkDerivation, base, containers, Dist, fgl, force-layout
      , generic-lens, jsaddle-warp, lens, linear, MonadRandom, mtl
      , random, reflex, reflex-dom, stdenv, text, these, time, z3
      }:
      mkDerivation {
        pname = "package";
        version = "0.1.0.0";
        src = ./.;
        isLibrary = true;
        isExecutable = true;
        libraryHaskellDepends = [
          base containers Dist fgl force-layout generic-lens jsaddle-warp
          lens linear MonadRandom mtl random reflex reflex-dom text these
          time z3
        ];
        executableHaskellDepends = [ base ];
        license = "unknown";
        hydraPlatforms = stdenv.lib.platforms.none;
      };

  haskellPackages = if compiler == "default"
                       then pkgs.haskellPackages
                       else pkgs.haskell.packages.${compiler};
  hspkgs = (
    if withHoogle then
      haskellPackages.override {
        overrides = (self: super: {
          ghc = super.ghc // { withPackages = super.ghc.withHoogle; };
          ghcWithPackages = self.ghc.withPackages;
        });
      }
      else haskellPackages
  );

  drv = hspkgs.callPackage f {};

in

  if pkgs.lib.inNixShell then drv.env else drv