def read_grammar(self, filename):
"""
语法读入
"""
grammar = self.grammar
grammar.clear()
self.terminators, self.non_terminators = [], []
g_in, g_out = defaultdict(int), defaultdict(int)
for l_hand, r_hand in bnf_reader(filename):
symbol = l_hand[1:-1]
__exp__ = [r[1:-1] for r in r_hand.split()]
for exp in __exp__:
g_in[exp] += 1
g_out[symbol] += 1
grammar[symbol].append(__exp__)
for k, v in g_in.iteritems():
if not g_out[k]:
self.terminators.append(k)
self.non_terminators.extend([k for k, v in g_out.iteritems() if v])
def read_lex(self, filename):
self.lexs = bnf_reader(filename)
def read_lex(self, filename):
self.lexs = bnf_reader(filename)
