{ mkDerivation, base, fetchurl }:
mkDerivation {
  pname = "harp";
  version = "0.4.3";
  src = fetchurl {
    url = "http://example.org/";
    sha256 = "abc";
  };
  libraryHaskellDepends = [ base ];
  homepage = "https://github.com/seereason/harp";
  description = "HaRP allows pattern-matching with regular expressions";
  license = stdenv.lib.licenses.bsd3;
}