anchor.diff: -{stdenv, fetchurl, ocaml, findlib, ocaml_react, opam}:
  +{stdenv, fetchurl, ocaml, findlib, ocaml_react, camlp4, opam}:
   
   let
     ocamlVersion = stdenv.lib.getVersion ocaml;
  
positive.code: assert stdenv.lib.versionAtLeast ocamlVersion "3.11";
  
  stdenv.mkDerivation {
    name = "ocaml-reactiveData-0.1";
    src = fetchurl {
      url = https://github.com/hhugo/reactiveData/archive/0.1.tar.gz;
      sha256 = "056y9in6j6rpggdf8apailvs1m30wxizpyyrj08xyfxgv91mhxgw";
    };
  
    buildInputs = [ocaml findlib opam];
    propagatedBuildInputs = [ocaml_react];
  
    buildPhase = "ocaml pkg/build.ml native=true native-dynlink=true";
  
negative.code: 
    meta = with stdenv.lib; {
      description = "An OCaml module for functional reactive programming (FRP) based on React";
      homepage = https://github.com/ocsigen/reactiveData;
      license = licenses.lgpl21;
      platforms = ocaml.meta.platforms or [];
      maintainers = with maintainers; [ vbgl ];
  