# Pastebin kP2iEKq0
let

  nixpkgsRev = "nixos-20.03";
  compilerVersion = "ghc883";

  githubTarball = owner: repo: rev:
    builtins.fetchTarball { url = "https://github.com/${owner}/${repo}/archive/${rev}.tar.gz"; };

  pkgs = import (githubTarball "NixOS" "nixpkgs-channels" nixpkgsRev) { inherit config; };
  
  config = {
    packageOverrides = super: let self = super.pkgs; in rec {
      haskellPackages = pkgs.haskell.packages."${compilerVersion}";
    };
  };
  
in pkgs.mkShell {
  buildInputs = [
    pkgs.haskellPackages.hakyll
  ];
}