code: protected void expect(Token.TokenType type, String trigger) {
          if (tokenizer.current().matches(type, trigger)) {
              tokenizer.consume();
          } else {
              errors.add(ParseError.error(tokenizer.current(),
                                          String.format("Unexpected token '%s'. Expected: '%s'",
                                                        tokenizer.current().getSource(),
                                                        trigger)));
          }
      }
docs: Signals that the given token is expected.
  <p>
  If the current input is pointing at the specified token, it will be consumed. If not, an error will be added
  to the error list and the input remains unchanged.
  
  @param type    the type of the expected token
  @param trigger the trigger of the expected token