anchor.diff:      "libjsonnet.so"
     ];
   
  +  # Upstream writes documentation in html, not in markdown/rst, so no
  +  # other output formats, sorry.
  +  preBuild = ''
  +    jekyll build --source ./doc --destination ./html
  +  '';
  +
     installPhase = ''
  -    mkdir -p $out/bin $out/lib $out/include
  +    mkdir -p $out/bin $out/lib $out/include $out/share/doc/jsonnet
       cp jsonnet $out/bin/
       cp jsonnetfmt $out/bin/
       cp libjsonnet*.so $out/lib/
       cp -a include/*.h $out/include/
  +    cp -r ./html $out/share/doc/jsonnet
     '';
   
     meta = {
  
positive.code:     repo = "jsonnet";
      sha256 = "1ddz14699v5lqx3dh0mb7hfffr6fk5zhmzn3z8yxkqqvriqnciim";
    };
  
    enableParallelBuilding = true;
  
  
negative.code: { stdenv, lib, jekyll, fetchFromGitHub }:
  
  stdenv.mkDerivation rec {
    pname = "jsonnet";
    version = "0.17.0";
    outputs = ["out" "doc"];
  
    src = fetchFromGitHub {
      rev = "v${version}";
  