anchor.diff:  
   format_msg_decoder(MsgName, MsgDef, AnRes, Opts) ->
       [format_msg_decoder_read_field(MsgName, MsgDef, AnRes),
  -     format_msg_decoder_reverse_toplevel(MsgName, MsgDef, AnRes),
        format_field_decoders(MsgName, MsgDef, AnRes, Opts),
        format_field_skippers(MsgName, AnRes)].
   
  
positive.code:                end
                 || {Field, Param} <- lists:zip(MsgDef, Params)]);
          pass_as_record ->
              RevFnName = mk_fn(d_reverse_toplevel_fields_, MsgName),
              ?expr('<reverse-toplevel-fields>'('<Params>'),
                    [{replace_term, '<reverse-toplevel-fields>', RevFnName},
                     {splice_trees, '<Params>', Params}])
      end.
  
  new_bindings(Tuples) ->
  
negative.code:         splice_trees('<OutFill>', OutFill),
          splice_trees('<OutParams>', Params2)]),
       "\n\n"].
  
  classify_field_merge_action(FieldDef) ->
      case FieldDef of
  