anchor.diff:  preview_execute(_IndexTable, _ID, _Type, _Strategies, _Term, Limit, _Iff, _PrevStrategy, _FromStu) when Limit =< 0 -> [];
   preview_execute(IndexTable, ID, Type, [exact_match | SearchStrategies], SearchTerm, Limit, Iff, undefined, FromStu) ->
       {atomic, ResultExact} =
  -        imem_if:transaction(fun() -> preview_exact(IndexTable, ID, Type, SearchTerm, ?SMALLEST_TERM, Limit, Iff) end),
  +        imem_if:transaction(fun() -> preview_exact(IndexTable, ID, Type, SearchTerm, ?SMALLEST_TERM, Limit, Iff, FromStu) end),
       ResultExact ++ preview_execute(IndexTable, ID, Type, SearchStrategies, SearchTerm, Limit - length(ResultExact), Iff, exact_match, FromStu);
   preview_execute(IndexTable, ID, Type, [head_match | SearchStrategies], SearchTerm, Limit, Iff, PrevStrategy, FromStu) ->
       StartingStu = if FromStu == <<>> -> create_starting_stu(Type, ID, head_match, SearchTerm);
  
positive.code:     #{<<"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] -> [];
  
negative.code: 
  %% @doc Preview match scan into an index for finding first "best" matches
  -spec preview(atom(),integer(),atom(),list(),term(),integer(),function(),function()) -> list().
  preview(IndexTable,ID,Type,SearchStrategies,SearchTerm,Limit,Iff,Vnf) ->
      preview(IndexTable,ID,Type,SearchStrategies,SearchTerm,Limit,Iff,Vnf,<<>>).
      % [{exact_match,<<"Key0">>,<<"Value0">>,{ID,<<"Value0">>,<<"Key0">>}}
  