def build_concatenation_nfa(first: NFA, second: NFA) -> NFA: for s in first.accepting_states: s.add_epsilon_transition(second.initial_state) return NFA(states=first.states.union(second.states), alphabet=first.alphabet.union(second.alphabet), initial_state=first.initial_state, accepting_states=second.accepting_states)
def build_symbol_nfa(s: str) -> NFA: initial, accepting = State("initial_{symbol}".format(symbol=s)), State( "accepting_{symbol}".format(symbol=s)) initial.add_transition(s, accepting) return NFA(states={initial, accepting}, alphabet={s}, initial_state=initial, accepting_states={accepting})
def build_closure_nfa(source: NFA) -> NFA: accepting = State("accepting_closure") initial = State("initial_closure", epsilon_transitions=[source.initial_state, accepting]) for s in source.accepting_states: s.add_epsilon_transitions([source.initial_state, accepting]) return NFA(states=source.states.union({initial, accepting}), alphabet=source.alphabet, initial_state=initial, accepting_states={accepting})
def build_union_nfa(first: NFA, second: NFA) -> NFA: initial, accepting = State("initial_union", epsilon_transitions=[first.initial_state, second.initial_state]), \ State("accepting_union") for sf, ss in zip(first.accepting_states, second.accepting_states): sf.add_epsilon_transition(accepting) ss.add_epsilon_transition(accepting) return NFA(states=first.states.union(second.states).union( {initial, accepting}), alphabet=first.alphabet.union(second.alphabet), initial_state=initial, accepting_states={accepting})
def startNFASemRule(self, lst, context=None): """ :param lst: :param context:""" new = NFA() new.Sigma = self.alphabet while self.states: x = self.states.pop() new.addState(x) while self.initials: x = self.initials.pop() new.addInitial(new.stateIndex(x)) while self.finals: x = self.finals.pop() new.addFinal(new.stateIndex(x)) while self.transitions: (x1, x2, x3) = self.transitions.pop() new.addTransition(new.stateIndex(x1), x2, new.stateIndex(x3)) self.theList.append(new) self.initLocal()
def getAutomata(self): """ deal with the information collected""" isDeterministic = True if len(self.initials) > 1 or "@epsilon" in self.states: isDeterministic = False else: for s in self.transitions: for c in self.transitions[s]: if len(self.transitions[s][c]) > 1: isDeterministic = False break if not isDeterministic: break if isDeterministic: if "l" in self.eq.keys(): fa = DFCA() fa.setLength = self.eq["l"] else: fa = DFA() else: fa = NFA() for s in self.states: fa.addState(s) fa.setFinal(fa.indexList(self.finals)) if isDeterministic: fa.setInitial(fa.stateIndex(common.uSet(self.initials))) for s1 in self.transitions: for c in self.transitions[s1]: fa.addTransition( fa.stateIndex(s1), c, fa.stateIndex(common.uSet(self.transitions[s1][c]))) else: fa.setInitial(fa.indexList(self.initials)) for s1 in self.transitions: for c in self.transitions[s1]: for s2 in fa.indexList(self.transitions[s1][c]): fa.addTransition(fa.stateIndex(s1), c, s2) return fa
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
import sys from fa import NFA, DFA filename = "test2.txt" file = open(filename, 'r') lines = file.readlines() file.close() nfa = NFA() dfa = DFA() nfa.construct_nfa_from_lines(lines) nfa.print_nfa() print() dfa.convert_from_nfa(nfa) dfa.print_dfa()