grammar.py 文件源码

def nonterminals(symbols):
    """
    Given a string containing a list of symbol names, return a list of
    ``Nonterminals`` constructed from those symbols.

    :param symbols: The symbol name string.  This string can be
        delimited by either spaces or commas.
    :type symbols: str
    :return: A list of ``Nonterminals`` constructed from the symbol
        names given in ``symbols``.  The ``Nonterminals`` are sorted
        in the same order as the symbols names.
    :rtype: list(Nonterminal)
    """
    if ',' in symbols: symbol_list = symbols.split(',')
    else: symbol_list = symbols.split()
    return [Nonterminal(s.strip()) for s in symbol_list]