def get_digits_enfa():
""" An epsilon NFA to recognize digits """
epsilon = Epsilon()
plus = Symbol("+")
minus = Symbol("-")
point = Symbol(".")
digits = [Symbol(x) for x in range(10)]
states = [State("q" + str(x)) for x in range(6)]
enfa = EpsilonNFA()
enfa.add_start_state(states[0])
enfa.add_final_state(states[5])
enfa.add_transition(states[0], epsilon, states[1])
enfa.add_transition(states[0], plus, states[1])
enfa.add_transition(states[0], minus, states[1])
for digit in digits:
enfa.add_transitions([(states[1], digit, states[1]),
(states[1], digit, states[4]),
(states[2], digit, states[3]),
(states[3], digit, states[3])])
enfa.add_transitions([(states[1], point, states[2]),
(states[4], point, states[3]),
(states[3], epsilon, states[5])])
return enfa, digits, epsilon, plus, minus, point
def test_automata_intersection():
states = [State(str(i)) for i in range(4)]
symb_a = Symbol('a')
symb_b = Symbol('b')
symb_c = Symbol('c')
enfa_1 = EpsilonNFA()
enfa_1.add_start_state(states[0])
enfa_1.add_transitions([
(states[0], symb_a, states[1]),
(states[1], symb_b, states[2]),
(states[2], symb_c, states[0])
])
enfa_1.add_final_state(states[0])
enfa_2 = EpsilonNFA()
enfa_2.add_start_state(states[0])
enfa_2.add_transitions([
(states[0], symb_a, states[1]),
(states[1], symb_b, states[1]),
(states[1], symb_c, states[2])
])
enfa_2.add_final_state(states[2])
result = enfa_1 & enfa_2
expected = EpsilonNFA()
expected.add_start_state(states[0])
expected.add_transitions([
(states[0], symb_a, states[1]),
(states[1], symb_b, states[2]),
(states[2], symb_c, states[3])
])
expected.add_final_state(states[3])
assert result.is_equivalent_to(expected)