{ nixpkgs ? import <nixpkgs> {}, compiler ? "default" }:

let

  inherit (nixpkgs) pkgs;

  f = { mkDerivation, ansi-wl-pprint, base, containers, criterion
      , data-fix, deepseq, deriving-compat, parsers, regex-tdfa
      , regex-tdfa-text, semigroups, stdenv, tasty, tasty-hunit, tasty-th
      , text, transformers, trifecta, unordered-containers
      }:
      mkDerivation {
        pname = "hnix";
        version = "0.4.0";
        src = ./.;
        isLibrary = true;
        isExecutable = true;
        libraryHaskellDepends = [
          ansi-wl-pprint base containers data-fix deepseq deriving-compat
          parsers regex-tdfa regex-tdfa-text semigroups text transformers
          trifecta unordered-containers
        ];
        executableHaskellDepends = [
          ansi-wl-pprint base containers data-fix deepseq
        ];
        testHaskellDepends = [
          base containers data-fix tasty tasty-hunit tasty-th text
        ];
        benchmarkHaskellDepends = [ base containers criterion text ];
        homepage = "http://github.com/jwiegley/hnix";
        description = "Haskell implementation of the Nix language";
        license = stdenv.lib.licenses.bsd3;
      };

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

  drv = haskellPackages.callPackage f {};

in

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