anchor.diff:              preview_range(IndexTable, ID, Type, {NormStart, NormEnd}, Limit, Iff)
       end;
   preview(IndexTable,ID,Type,SearchStrategies,SearchTerm,Limit,Iff,Vnf) ->
  -    case Vnf(SearchTerm) of
  -        [?nav] -> [];
  -        [NormalizedTerm | _] ->
  -            case is_regexp_search(SearchStrategies, NormalizedTerm) of
  -                true ->
  -                    preview_regexp(IndexTable, ID, Type, NormalizedTerm, Limit, Iff);
  -                false ->
  -                    FilteredStrategies = [Strategy || Strategy <- SearchStrategies, Strategy =/= re_match],
  -                    preview_execute(IndexTable, ID, Type, FilteredStrategies, NormalizedTerm, Limit, Iff, undefined)
  -            end
  -    end.
  +    preview(IndexTable,ID,Type,SearchStrategies,SearchTerm,Limit,Iff,Vnf,<<>>).
       % [{exact_match,<<"Key0">>,<<"Value0">>,{ID,<<"Value0">>,<<"Key0">>}}
       % ,{head_match,<<"Key1">>,<<"Value1">>,{ID,<<"Value1">>,<<"Key1">>}}
       % ,{body_match,<<"Key2">>,<<"Value2">>,{ID,<<"Value2">>,<<"Key2">>}}
  
positive.code:         _ -> Acc
      end.
  
  preview_exact(_IndexTable, _ID, _Type, _SearchTerm, _Key, 0, _Iff) -> [];
  preview_exact(IndexTable, ID, ivk, SearchTerm, Key, Limit, Iff) ->
      lists:reverse(preview_exact_unique(IndexTable, ID, SearchTerm, Key, Limit, Iff, []));
  preview_exact(IndexTable, ID, iv_k, SearchTerm, _Key, _Limit, Iff) ->
      case imem_if:read(IndexTable, {ID, SearchTerm}) of
          [#ddIndex{stu = {ID, SearchTerm}, lnk = Key} = Entry] ->
  
negative.code:     % ].
  
  %% @doc Preview match scan into an index for finding first "best" matches
  -spec preview(atom(),integer(),atom(),list(),term(),integer(),function(),function(),map() | tuple()) -> list().
  preview(IndexTable,ID,Type,SearchStrategies,SearchTerm,Limit,Iff,Vnf, 
      #{<<"match_info">> := Match}) ->
      {_,_,_, FromStu} = binary_to_term(base64:decode(Match)),
      preview(IndexTable,ID,Type,SearchStrategies,SearchTerm,Limit,Iff,Vnf,FromStu);
  preview(IndexTable,ID,Type,SearchStrategies,SearchTerm,Limit,Iff,Vnf,FromStu) ->
      case Vnf(SearchTerm) of
          [?nav] -> [];
          [NormalizedTerm | _] ->
              case is_regexp_search(SearchStrategies, NormalizedTerm) of
                  true ->
                      preview_regexp_init(IndexTable, ID, Type, NormalizedTerm, Limit, Iff, FromStu);
                  false ->
                      FilteredStrategies = [Strategy || Strategy <- SearchStrategies, Strategy =/= re_match],
                      preview_execute(IndexTable, ID, Type, FilteredStrategies, NormalizedTerm, Limit, Iff, undefined, FromStu)
              end
      end.
      %% ToDo: implement continuation search
      % [{exact_match,<<"Key0">>,<<"Value0">>,{ID,<<"Value0">>,<<"Key0">>}}
      % ,{head_match,<<"Key1">>,<<"Value1">>,{ID,<<"Value1">>,<<"Key1">>}}
      % ,{body_match,<<"Key2">>,<<"Value2">>,{ID,<<"Value2">>,<<"Key2">>}}
  