anchor.diff:              pkg = "language-c";
               ver = "0.9";
               sha256 = "1dxi56aawabq2ds6crvhhr9dwmbyanjkn9l0yhw7wcqrwx71kliq";
  -          } {};
  +          } { };
           } // pkgs.lib.optionalAttrs hoogle {
             ghc = super.ghc // { withPackages = super.ghc.withHoogle; };
             ghcWithPackages = p:
  
positive.code:   haskellPackages = with pkgs.haskell.lib;
      pkgs.haskell.packages.${compiler'}.override {
        overrides = self: super:
          (pkgs.lib.mapAttrs (n: v: makeDrv n v) targets) // {
            #
            # Examples
            #
  
negative.code: 
    targets = let
      srcFilter = path: type:
        (baseNameOf path == "package.yaml") || pkgs.lib.hasInfix "/src" path
        || pkgs.lib.hasInfix "/vk" path || pkgs.lib.hasInfix "/vma" path;
      filter = builtins.filterSource srcFilter;
    in {
      vulkan = filter ./.;
  