anchor.diff:    snapshotJson = pkgs.stdenv.mkDerivation rec {
       inherit haxe haxeSrc haxeTestSrc;
       name = "hsluv-haxe-test";
  -    builder = builtins.toFile "builder.sh" ''
  -      source $stdenv/setup
  -      $haxe/bin/haxe -cp $haxeSrc -cp $haxeTestSrc -main Snapshot --interp > $out
  +    buildInputs = [haxe];
  +    builder = builtins.toFile "builder.sh" ''
  +      source $stdenv/setup
  +      haxe -cp $haxeSrc -cp $haxeTestSrc -main Snapshot --interp > $out
       '';
     };
   
  
positive.code:   nodejs = pkgs.nodejs;
    gnupg = pkgs.gnupg;
    luarocks = pkgs.luarocks;
    python3 = pkgs.python3;
    ruby = pkgs.ruby;
    maven = pkgs.maven;
    wheel = pkgs.python3Packages.wheel;
    awscli = pkgs.python3Packages.awscli;
    nuget = pkgs.dotnetPackages.Nuget;
    openssl = pkgs.openssl;
  
negative.code:   snapshotRev4 = ./snapshots/snapshot-rev4.json;
    closureCompiler = pkgs.closurecompiler;
  
    python = pkgs.python36.withPackages (ps: with ps; [ setuptools wheel ]);
  
    # v0.0.2
    pythonSrc = pkgs.fetchzip {
      url = "https://github.com/hsluv/hsluv-python/archive/287439082df640fe469a1af5b683bcd7a14c4b54.zip";
  