code: public boolean consume(String token) {
          if (getInput().toString().startsWith(token)) {
              index += token.length();
              return true;
          }
          return false;
      }
docs: Consumes the given token. If the current residual text to be parsed
  starts with the parsing index is increased by {@code token.size()}.
  
  @param token The token expected.
  @return true, if the token could be consumed and the index was increased
  by {@code token.size()}.