anchor.diff:      name = "hsluv-website-demo-images";
       inherit nodejs nodeModules;
       generateImagesJs = ./website/generate-images.js;
  +    buildInputs = [nodejs];
       builder = builtins.toFile "builder.sh" ''
         source $stdenv/setup
         export NODE_PATH=$nodeModules:$NODE_PATH
         mkdir $out
  -      $nodejs/bin/node $generateImagesJs --website $out
  +      node $generateImagesJs --website $out
       '';
     };
   
  
positive.code: 
    pythonDist = pkgs.stdenv.mkDerivation rec {
      name = "python-dist";
      inherit python3 pythonSrc wheel;
      builder = builtins.toFile "builder.sh" ''
        source $stdenv/setup
        export PATH=$python3/bin:$PATH
        export PYTHONPATH=$PYTHONPATH:$wheel/lib/python3.5/site-packages
        export SOURCE_DATE_EPOCH=315532800
        cp -R --no-preserve=mode,ownership $pythonSrc/* .
        python setup.py sdist bdist_wheel
  
negative.code:     '';
    };
  
    haxeTest = pkgs.stdenv.mkDerivation rec {
      inherit haxe haxeSrc haxeTestSrc snapshotRev4;
      name = "hsluv-haxe-test";
      buildInputs = [haxe];
      builder = builtins.toFile "builder.sh" ''
        source $stdenv/setup
        haxe -cp $haxeSrc -cp $haxeTestSrc -main RunTests -resource $snapshotRev4@snapshot-rev4 --interp
        touch $out
      '';
    };
  