code: protected Token fetchSpecialId() {
          Token result = Token.create(Token.TokenType.SPECIAL_ID, input.current());
          result.addToTrigger(input.consume());
          while (isIdentifierChar(input.current())) {
              result.addToContent(input.consume());
          }
          return handleKeywords(result);
      }
docs: Reads and returns a special id.
  
  @return the parsed special id as Token