anchor.diff:  %%----------------------------------------------------------------------------
   %% API
   %%----------------------------------------------------------------------------
  +
  +create_index(_DomId, _CatId, File) ->
  +    %% add domain
  +    %% add cat
  +    %% open file
  +    {ok, Binary} = file:read_file(File),
  +    %% build "posts list" (i.e. [{Term, DocId}, {Term, DocId}, ...])
  +    posts_list(Binary).
   
   %% @doc Adds a document.
   add_doc(DomId, CatId, DocId, Doc) ->
  
positive.code: -module(dk_in).
  
  %% API
  -export([add_doc/4]).
  
  %% For internal use only
  -export(['_add_doc'/4]).
  
negative.code: %%----------------------------------------------------------------------------
  %% Internal functions
  %%----------------------------------------------------------------------------
  
  posts_list(Binary) ->
      posts_list(Binary, []).
  
  posts_list(<<>>, Acc) ->
      Acc;
  posts_list(Binary, Acc) ->
      [Line, Rest] = binary:split(Binary, <<"\n">>), %% does this work correctly with UTF-8?
      [Id, Text] = binary:split(Line, <<" ">>),
      _Terms = dk_pp:terms(Text, "en"),
      posts_list(Rest, [Id | Acc]).
  
  %% @private
  '_add_doc'(DomId, CatId, DocId, Doc) ->
  