anchor.diff:      baseName = "FSharp.Data";
       version = "2.2.3";
   
  -    src = fetchurl {
  -      name = "${baseName}-${version}.tar.gz";
  -      url = "https://github.com/fsharp/FSharp.Data/archive/${version}.tar.gz";
  -      sha256 = "162ncwjyc74ndh3m5dpppg9aag1f8ijkjwv5dx0mid3mw592bjh1";
  +    src = fetchFromGitHub {
  +      owner = "fsharp";
  +      repo = baseName;
  +      rev = version;
  +      sha256 = "1h3v9rc8k0khp61cv5n01larqbxd3xcx3q52sw5zf9l0661vw7qr";
       };
   
       buildInputs = [ fsharp ];
  
positive.code: 
    # SOURCE PACKAGES
  
    ExcelDna = buildDotnetPackage rec {
      baseName = "Excel-DNA";
      version = "0.32.0";
  
negative.code:     outputFiles = [ "Lib/Net40/*" ];
    };
  
    FSharpFormatting = fetchNuGet {
      baseName = "FSharp.Formatting";
      version = "2.9.8";
      sha256 = "1bswcpa68i2lqds4kkl2qxgkfrppbpxa4jkyja48azljajh0df3m";
      outputFiles = [ "lib/net40/*" ];
    };
  
    NUnit = fetchNuGet {
      baseName = "NUnit";
      version = "2.6.4";
  