anchor.diff:  
   rev_to_str({Pos, RevId}) ->
       ?l2b([integer_to_list(Pos),"-",revid_to_str(RevId)]).
  -                    
  -                    
  +
  +
   revs_to_strs([]) ->
       [];
   revs_to_strs([{Pos, RevId}| Rest]) ->
  
positive.code:     MergedBins = lists:map(
          fun(#att{name=Name, data=stub, revpos=StubRevPos}) ->
              case dict:find(Name, BinDict) of
              {ok, #att{revpos=DiskRevPos}=DiskAtt} 
                      when DiskRevPos == StubRevPos orelse StubRevPos == nil ->
                  DiskAtt;
              _ ->
  
negative.code:         end),
      Ref = make_ref(),
      Parser ! {get_doc_bytes, Ref, self()},
      receive
      {doc_bytes, Ref, DocBytes} ->
          Doc = from_json_obj(?JSON_DECODE(DocBytes)),
          % go through the attachments looking for 'follows' in the data,
  