anchor.diff:  
   scan_string_backslash(LI, Acc) ->
     case scan_inline_escape(LI) of
  -    Val when is_number(Val) ->
  -      scan_string(LI, [Val | Acc]);
  +    Ch when is_integer(Ch) ->
  +      scan_string(LI, [Ch | Acc]);
       {error, Ch} ->
         case es_ctype:char_is_whitespace(Ch) of
           true ->
  
positive.code: 
  scan_vi_backslash(LI, Acc) ->
    case scan_inline_escape(LI) of
      Val when is_number(Val) ->
        scan_vi(LI, [Val | Acc]);
      {error, Ch} ->
        lexer_error({invalid_character, Ch})
    end.
  
negative.code:       io_lib:format("invalid character: ~p", [Ch]);
      {invalid_character_name, Str} ->
        io_lib:format("invalid character name: ~s", [Str]);
      {invalid_identifier, Str} ->
        io_lib:format("invalid identifier: ~s", [Str]);
      {invalid_identifier, Str, Ch} ->
  