def compile(self, grammar_type="regex"):
"""
根据文法类型进行编译, 产生dfa. regex 表示 正则表达式, regular 表示 正规文法
:param grammar: 文法类型
:return:
"""
if grammar_type == 'regex':
nfas = []
for le in self.lexs:
# print le
nfas.append(Regex.compile_nfa(le[1], extend=True, type=le[0]))
nfa = NFA.combine(*nfas)
self.lex_dfa = nfa.convert_dfa(copy_meta=["type"])
return
elif grammar_type == "regular":
"""
本来没有想到会做三型文法解析, 由于parser里也有文法解析.. 此处应该跟那边合并..
"""
nfas = []
grammar = defaultdict(list)
g_in, g_out = defaultdict(int), defaultdict(int)
all_symbol = set()
for l_hand, r_hand in self.lexs:
l_hand = l_hand[1:-1]
r_hands = [[x[1:-1] for x in r.strip().split()]
for r in r_hand.split('|')]
for hand in r_hands:
for h in hand:
g_in[h] += 1
all_symbol.add(h)
g_out[l_hand] += 1
all_symbol.add(l_hand)
grammar[l_hand].extend(r_hands)
grammar['limit'] = [[' '], ['\t'], ['\n']]
ter, not_ter = [], []
for sym in all_symbol:
if g_in[sym] == 0:
not_ter.append(sym)
if g_out[sym] == 0:
ter.append(sym)
# print ter, not_ter
nfas = []
for token_type in not_ter:
nfa = NFA()
nfa.start = NFANode(r_name=token_type)
end_node = NFANode(type=token_type)
end_node.end = True
nfa.end = {end_node}
vis = {token_type: nfa.start}
def get_node(name):
if name in vis:
return vis[name]
vis[name] = NFANode(r_name=name)
return vis[name]
que = Queue()
que.put(token_type)
while not que.empty():
t = que.get()
node = get_node(t)
if node.meta.get('vis', 0) > 0:
continue
node.meta['vis'] = node.meta.get('vis', 0) + 1
for r_hand in grammar[t]:
node.next.setdefault(r_hand[0], set())
if len(r_hand) == 2:
node.next[r_hand[0]].add(get_node(r_hand[1]))
que.put(r_hand[1])
else:
node.next[r_hand[0]].add(end_node)
nfas.append(nfa)
nfa = NFA.combine(*nfas)
self.lex_dfa = nfa.convert_dfa(copy_meta=["type"])
return
def get_node(name):
if name in vis:
return vis[name]
vis[name] = NFANode(r_name=name)
return vis[name]
