anchor.diff:  		   delete = make_token_delete_filter(TokenFilter),
   		   stats = make_token_stats(TokenFilter)};
   make_token_filter(_) ->
  -    asn1_NOVALUE.
  +    undefined.
   
   make_token_transform(#{transform := lowercase}) ->
       'LOWERCASE';
  
positive.code: make_token_transform(#{transform := casefold}) ->
      'CASEFOLD';
  make_token_transform(_) ->
      asn1_NOVALUE.
  
  make_token_add_filter(#{add := L}) when is_list(L) ->
      L;
  
negative.code: 			 threshold = <<>>,
  			 set_value = <<>>}.
  
  -spec make_index_config(IndexConfig :: [{Column :: string(), Opts :: map()}]) ->
      [#'IndexConfig'{}].
  make_index_config(IndexConfig) ->
      make_index_config(IndexConfig, []).
  
  make_index_config([{Column, Config} | Rest], Acc) ->
      IndexConfig = #'IndexConfig'{column = Column,
  				 options = make_index_options(Config)},
      make_index_config(Rest, [IndexConfig | Acc]);
  make_index_config([Column | Rest], Acc) when is_list(Column)->
      IndexConfig = #'IndexConfig'{column = Column},
      make_index_config(Rest, [IndexConfig | Acc]);
  make_index_config([], Acc) ->
      lists:reverse(Acc).
  
  make_index_options(Config) when is_map(Config) ->
     #'IndexOptions'{char_filter = make_char_filter(Config),
  		   tokenizer = make_tokenizer(Config),
  		   token_filter = make_token_filter(Config)};
  make_index_options(_) ->
      undefined.
  
  make_char_filter(#{char_filter := nfc}) ->
      'NFC';
  