shell.nix

{ nixpkgs     ? import <nixpkgs> {}
, pkgs        ? nixpkgs.pkgs, haskell ? pkgs.haskell
, compiler    ? "ghc802"
, ghcOrig     ? pkgs.haskell.packages."${compiler}"
, localYT     ? false
}:
let
  overcabal = pkgs.haskell.lib.overrideCabal;
  hubsrc    =      repo: rev: sha256:       pkgs.fetchgit { url = "https://github.com/" + repo; rev = rev; sha256 = sha256; };
  overc     = old:                    args: overcabal old (oldAttrs: (oldAttrs // args));
  overhub   = old: repo: rev: sha256: args: overc old ({ src = hubsrc repo rev sha256; }       // args);
  overhage  = old: version:   sha256: args: overc old ({ version = version; sha256 = sha256; } // args);

  ghc       = ghcOrig.override (oldArgs: {
    overrides = with haskell.lib; new: old:
    let parent = (oldArgs.overrides or (_: _: {})) new old;
    in with new; parent // {
      unicode-show = dontCheck old.unicode-show;
    };
  });

  ###
  nakeDrv = ghc.callPackage (import ./.) {};
  drv = (haskell.lib.addBuildTools nakeDrv
         [ pkgs.cabal-install
           pkgs.stack
           ghc.intero
         ]);
in if pkgs.lib.inNixShell then drv.env else drv