def test_to_regex3(self):
""" Tests the transformation to regex """
enfa = EpsilonNFA()
state0 = State(0)
state1 = State(1)
symb_a = Symbol("0")
symb_b = Symbol("1")
enfa.add_start_state(state0)
enfa.add_final_state(state1)
enfa.add_transition(state0, symb_a, state0)
enfa.add_transition(state1, symb_b, state0)
enfa.add_transition(state1, symb_b, state1)
regex = enfa.to_regex()
enfa2 = regex.to_epsilon_nfa()
self.assertFalse(enfa2.accepts([symb_a]))
self.assertFalse(enfa2.accepts([symb_a, symb_a]))
self.assertFalse(enfa2.accepts([symb_a, symb_a, symb_b]))
self.assertFalse(
enfa2.accepts([symb_a, symb_a, symb_b, symb_b, symb_a]))
self.assertFalse(
enfa2.accepts([symb_a, symb_a, symb_b, symb_b, symb_a, symb_b]))
self.assertFalse(enfa2.accepts([symb_b]))
epsilon = Epsilon()
enfa.add_transition(state0, epsilon, state1)
regex = enfa.to_regex()
enfa2 = regex.to_epsilon_nfa()
self.assertTrue(enfa.accepts([]))
self.assertTrue(enfa.accepts([symb_a]))
self.assertTrue(enfa2.accepts([symb_a]))
self.assertTrue(enfa2.accepts([symb_a, symb_a]))
self.assertTrue(enfa2.accepts([symb_a, symb_a, symb_b, symb_b]))
self.assertTrue(
enfa2.accepts([symb_a, symb_a, symb_b, symb_b, symb_a, symb_b]))
self.assertTrue(enfa2.accepts([symb_b]))
self.assertTrue(enfa2.accepts([]))
enfa.remove_transition(state0, symb_a, state0)
regex = enfa.to_regex()
enfa2 = regex.to_epsilon_nfa()
self.assertFalse(enfa2.accepts([symb_a]))
self.assertFalse(enfa2.accepts([symb_a, symb_a]))
self.assertFalse(enfa2.accepts([symb_a, symb_a, symb_b]))
self.assertFalse(
enfa2.accepts([symb_a, symb_a, symb_b, symb_b, symb_a]))
self.assertFalse(
enfa2.accepts([symb_a, symb_a, symb_b, symb_b, symb_a, symb_b]))
self.assertTrue(enfa2.accepts([symb_b]))
self.assertTrue(enfa2.accepts([]))
enfa.remove_transition(state1, symb_b, state1)
regex = enfa.to_regex()
enfa2 = regex.to_epsilon_nfa()
self.assertTrue(enfa2.accepts([symb_b, symb_b]))
enfa.add_transition(state0, symb_a, state0)
regex = enfa.to_regex()
enfa2 = regex.to_epsilon_nfa()
self.assertTrue(enfa2.accepts([symb_a, symb_b]))
def test_to_regex(self):
""" Tests the transformation to regex """
enfa = EpsilonNFA()
state0 = State(0)
state1 = State(1)
state2 = State(2)
symb_e = Symbol("e")
symb_f = Symbol("f")
symb_g = Symbol("g")
enfa.add_start_state(state0)
enfa.add_final_state(state2)
enfa.add_transition(state0, symb_e, state1)
enfa.add_transition(state1, symb_f, state2)
enfa.add_transition(state0, symb_g, state2)
regex = enfa.to_regex()
enfa2 = regex.to_epsilon_nfa()
self.assertTrue(enfa2.accepts([symb_e, symb_f]))
self.assertTrue(enfa2.accepts([symb_g]))
self.assertFalse(enfa2.accepts([]))
self.assertFalse(enfa2.accepts([symb_e]))
self.assertFalse(enfa2.accepts([symb_f]))
enfa.add_final_state(state0)
with self.assertRaises(ValueError) as _:
enfa.get_regex_simple()
regex = enfa.to_regex()
enfa3 = regex.to_epsilon_nfa()
self.assertTrue(enfa3.accepts([symb_e, symb_f]))
self.assertTrue(enfa3.accepts([symb_g]))
self.assertTrue(enfa3.accepts([]))
self.assertFalse(enfa3.accepts([symb_e]))
self.assertFalse(enfa3.accepts([symb_f]))
enfa.remove_start_state(state0)
regex = enfa.to_regex()
enfa3 = regex.to_epsilon_nfa()
self.assertFalse(enfa3.accepts([symb_e, symb_f]))
self.assertFalse(enfa3.accepts([symb_g]))
self.assertFalse(enfa3.accepts([]))
self.assertFalse(enfa3.accepts([symb_e]))
self.assertFalse(enfa3.accepts([symb_f]))
enfa.add_start_state(state0)
enfa.add_transition(state0, symb_f, state0)
regex = enfa.to_regex()
enfa3 = regex.to_epsilon_nfa()
self.assertTrue(enfa3.accepts([symb_e, symb_f]))
self.assertTrue(enfa3.accepts([symb_f, symb_e, symb_f]))
self.assertTrue(enfa3.accepts([symb_g]))
self.assertTrue(enfa3.accepts([symb_f, symb_f, symb_g]))
self.assertTrue(enfa3.accepts([]))
self.assertFalse(enfa3.accepts([symb_e]))
self.assertTrue(enfa3.accepts([symb_f]))
def test_example_doc(self):
enfa = EpsilonNFA()
state0 = State(0)
state1 = State(1)
symb_a = Symbol("0")
symb_b = Symbol("1")
enfa.add_start_state(state0)
enfa.add_final_state(state1)
enfa.add_transition(state0, symb_a, state0)
enfa.add_transition(state1, symb_b, state0)
enfa.add_transition(state1, symb_b, state1)
# Turn a finite automaton into a regex...
regex = enfa.to_regex()
# And turn it back into an epsilon non deterministic automaton
enfa2 = regex.to_epsilon_nfa()