grammar.py 文件源码

def __init__(self, start, productions):
        """
        Create a new feature-based grammar, from the given start
        state and set of ``Productions``.

        :param start: The start symbol
        :type start: FeatStructNonterminal
        :param productions: The list of productions that defines the grammar
        :type productions: list(Production)
        """
        CFG.__init__(self, start, productions)

    # The difference with CFG is that the productions are
    # indexed on the TYPE feature of the nonterminals.
    # This is calculated by the method _get_type_if_possible().