__init__.py 文件源码

def __AcceptRegex(self, regex):
    """Advance and return the symbol if the next symbol matches the regex.

    Args:
      regex: the compiled regular expression to attempt acceptance on.

    Returns:
      The first group in the expression to allow for convenient access
      to simple matches. Requires () around some objects in the regex.
      None if no match is found.
    """
    if self.__next_symbol < len(self.__symbols):
      match_symbol = self.__symbols[self.__next_symbol]
      logging.log(LOG_LEVEL, '\taccept %s on symbol %s', regex, match_symbol)
      match = regex.match(match_symbol)
      if match:
        self.__next_symbol += 1
        if match.groups():
          matched_string = match.group(1)

        logging.log(LOG_LEVEL, '\taccepted %s', matched_string)
        return matched_string

    return None