anchor.diff:  get_value(Path, Config, State) ->
       case get_values(Path, Config, State) of
           [] -> undefined;
  -        [One] -> One;
  +        [One] -> wf:to_list(One);
           _Many -> throw({?MODULE, too_many_matches, Path})
       end.
   
  
positive.code:     F = fun({KeyPartsReversed, Value}) ->
          KeyParts = lists:reverse(KeyPartsReversed),
          Key = string:join(KeyParts, "."),
          { Key, Value }
      end,
      lists:map(F, Params).
  
  
negative.code: %%   Path   = [b, c]
  %%   Params = [y, b, c]
  refine_params([], Params) -> 
      [wf:to_list(V) || {_, V} <- Params];
  refine_params([H|T], Params) ->
      F = fun({Path, Value}, Acc) ->
          case split_on(H, Path) of
  