{ pkgs ? (import <nixpkgs> {})
, compilerName ? "ghc801"
}:

rec {
  # haskellPackages = pkgs.haskell.packages."${compilerName}";
  haskellPackages = pkgs.haskell.packages."${compilerName}".override {
    overrides = self: super: {
      Shellac = pkgs.stdenv.lib.overrideDerivation super.Shellac (oldAttrs: {
        src = pkgs.fetchFromGitHub {
          owner = "pngwjpgh";
          repo = "shellac";
          rev = "b88a92bace5106e7446bc81688d675994f829282";
          sha256 = "1qpnbnclz1xwisg9wgs4yl8y0ral01pqy8jnq6g7z1xbc8p6qn0i";
        };
      });
      Shellac-haskeline = pkgs.stdenv.lib.overrideDerivation super.Shellac-haskeline (oldAttrs: {
        src = pkgs.fetchFromGitHub {
          owner = "pngwjpgh";
          repo = "shellac";
          rev = "b88a92bace5106e7446bc81688d675994f829282";
          sha256 = "1qpnbnclz1xwisg9wgs4yl8y0ral01pqy8jnq6g7z1xbc8p6qn0i";
        };
        unpackPhase = "cp -r $src/shellac-haskeline/. .";
      });
    };
  };
  sequence = haskellPackages.callPackage ./sequence.nix {};
}