anchor.diff: -{ stdenv, makeWrapper, buildOcaml, fetchFromGitHub,
  -  ocaml, opam, jbuilder, menhir, merlin_extend, ppx_tools_versioned, utop }:
  +{ stdenv, makeWrapper, fetchFromGitHub, ocaml, findlib, jbuilder
  +, menhir, merlin_extend, ppx_tools_versioned, utop
  +}:
   
  -buildOcaml rec {
  -  name = "reason";
  +stdenv.mkDerivation rec {
  +  name = "ocaml${ocaml.version}-reason-${version}";
     version = "3.3.3";
   
     src = fetchFromGitHub {
  
positive.code: 
    propagatedBuildInputs = [ menhir merlin_extend ppx_tools_versioned ];
  
    buildInputs = [ makeWrapper opam jbuilder utop menhir ];
  
    buildFlags = [ "build" ]; # do not "make tests" before reason lib is installed
  
    createFindlibDestdir = true;
  
    installPhase = ''
      for p in reason rtop
  
negative.code:     homepage = https://reasonml.github.io/;
      description = "Facebook's friendly syntax to OCaml";
      license = licenses.mit;
      inherit (ocaml.meta) platforms;
      maintainers = [ maintainers.volth ];
    };
  }
  