# Pastebin qYqmrf4U
{ nixpkgs ? import <nixpkgs> { config = { allowUnsupportedSystem = true; }; }
, compiler ? "default", doBenchmark ? false
}:

let

  inherit (nixpkgs) pkgs;
  haskellLib = import <nixpkgs/pkgs/development/haskell-modules/lib.nix> { inherit pkgs; inherit (pkgs) lib; } ;

  f = { mkDerivation, array, attoparsec, base, bmp, bytestring
      , containers, cpphs, directory, either, filepath, free, gloss_1_13_0_1
      , gloss-juicy, hashable, Hclip, hint, hosc, JuicyPixels, language-c
      , lens, mmorph, MoodlerLib, mtl, optparse-applicative, PortMidi
      , pretty, process, stdenv, syb, temporary, text, transformers
      , uniplate, unix
      , portaudio
      }:
      mkDerivation rec {
        pname = "Moodler";
        version = "0.1.0.0";
        src = ./.;
        isLibrary = false;
        isExecutable = true;
        executableHaskellDepends = [
          array attoparsec bmp bytestring containers cpphs directory
          either filepath free gloss_1_13_0_1 gloss-juicy hashable Hclip hint hosc
          JuicyPixels language-c lens mmorph MoodlerLib mtl
          optparse-applicative PortMidi pretty process syb temporary text
          transformers uniplate unix
        ];

        librarySystemDepends = [ portaudio ];

        description = "A modular synthesiser";
        license = stdenv.lib.licenses.bsd2;


        shellHook = ''
          export C_INCLUDE_PATH = \
            ${stdenv.lib.makeSearchPathOutput "dev" "include" librarySystemDepends}
          export LIBRARY_PATH = \
            ${stdenv.lib.makeLibraryPath librarySystemDepends}
        '';
        FOO="foo";

      };

  haskellPackages = if compiler == "default"
                       then pkgs.haskellPackages
                       else pkgs.haskell.packages.${compiler};

  modifiedHaskellPackages = haskellPackages.override {
      overrides = self: super: {
        MoodlerLib = self.callPackage ../MoodlerLib {};
        gloss-juicy = super.gloss-juicy.override {
          gloss = super.gloss_1_13_0_1;
        };
      };
    };

  variant = if doBenchmark then pkgs.haskell.lib.doBenchmark else pkgs.lib.id;

  drv = variant (modifiedHaskellPackages.callPackage f {});

in

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