anchor.diff:  
       dontStrip = true;
   
  -    meta = with stdenv.lib; {
  -      description = "Tools for authors of ppx rewriters";
  -      homepage = http://www.lexifi.com/ppx_tools;
  -      license = licenses.mit;
  -      platforms = ocaml.meta.platforms or [];
  -      maintainers = with maintainers; [ vbgl ];
  -    };
  +    meta = meta // { inherit (ocaml.meta) platforms; };
     }
  
positive.code: { stdenv, fetchFromGitHub, ocaml, findlib }:
  
  let param = {
    "4.02" = {
  
negative.code:     version = "5.3+4.08.0";
      sha256 = "0vdmhs3hpmh5iclx4lzgdpf362m4l35zprxs73r84z1yhr4jcr4m"; };
    "4.09" = {
      version = "6.0+4.08.0";
      sha256 = "056cmdajap8mbb8k0raj0cq0y4jf7pf5x0hlivm92w2v7xxf59ns"; };
    "4.10" = {
      version = "6.1+4.10.0";
      sha256 = "0ccx2g4zpwnv52bbzhgxji1nvzmn80jwiqalwwc4s60i9qg51llw"; };
  }.${ocaml.meta.branch};
  in
  
  let src = fetchFromGitHub {
        owner = "alainfrisch";
        repo = pname;
        rev = param.rev or param.version;
        inherit (param) sha256;
      };
      pname = "ppx_tools";
      meta = with stdenv.lib; {
        description = "Tools for authors of ppx rewriters";
        homepage = http://www.lexifi.com/ppx_tools;
        license = licenses.mit;
        maintainers = with maintainers; [ vbgl ];
      };
  in
  if stdenv.lib.versionAtLeast param.version "6.0"
  then
    buildDunePackage {
      inherit pname src meta;
      inherit (param) version;
    }
  else
    stdenv.mkDerivation {
      name = "ocaml${ocaml.version}-${pname}-${param.version}";
  
      inherit src;
  
      nativeBuildInputs = [ ocaml findlib ];
      buildInputs = [ ocaml findlib ];
  