{ pkgs ? import (
  builtins.fetchGit {
    name = "nixpkgs-pinned";
    url = https://github.com/NixOS/nixpkgs/;
    ref = "refs/heads/release-20.03";
    rev = "da7ddd822e32aeebea00e97ab5aeca9758250a40";
  }) {},
  compiler ? "ghc865"
}:

let
  hp = pkgs.haskell.packages."${compiler}";
  src = pkgs.nix-gitignore.gitignoreSource [] ./.;
  drv = hp.callCabal2nix "Hash2Pub" "${src}/Hash2Pub.cabal" {};
in
{
  my_project = drv;
  shell = hp.shellFor {
    withHoogle = true;
    packages = p: [ drv ];
    buildInputs = with hp;
      [
        haddock
        cabal-install
        hlint
        pkgs.python3Packages.asn1ate
      ];
  };
}