def test_to_CFG(self):
states = [PDAState("q0"), PDAState("q1"), PDAState("q2")]
input_symbols = [0, 1]
stack_alphabet = [0, 1, "end"]
transition_function = []
transition_function.append(
PDATransitionFunction(states[0], 0, "end", states[0], [0, "end"]))
transition_function.append(
PDATransitionFunction(states[0], 1, "end", states[0], [1, "end"]))
transition_function.append(
PDATransitionFunction(states[0], 0, 0, states[0], [0, 0]))
transition_function.append(
PDATransitionFunction(states[0], 0, 1, states[0], [0, 1]))
transition_function.append(
PDATransitionFunction(states[0], 1, 1, states[0], [1, 1]))
transition_function.append(
PDATransitionFunction(states[0], 1, 0, states[0], [1, 0]))
transition_function.append(
PDATransitionFunction(states[0], "epsilon", "end", states[1],
["end"]))
transition_function.append(
PDATransitionFunction(states[0], "epsilon", 0, states[1], [0]))
transition_function.append(
PDATransitionFunction(states[0], "epsilon", 1, states[1], [1]))
transition_function.append(
PDATransitionFunction(states[1], 0, 0, states[1], []))
transition_function.append(
PDATransitionFunction(states[1], 1, 1, states[1], []))
transition_function.append(
PDATransitionFunction(states[1], "epsilon", "end", states[2], []))
start_state = states[0]
start_symbol = "end"
final_states = [states[2]]
pda = PDA(states, input_symbols, stack_alphabet, transition_function,
start_state, start_symbol, final_states)
cfg = pda.to_CFG()
self.assertIsInstance(cfg, CFG)
self.assertFalse(cfg.is_empty())
it = iter(cfg)
for _ in range(50):
temp = next(it)
self.assertGreaterEqual(len(temp), 0)
self.assertEqual(temp, temp[::-1])
def test_stack_to_end(self):
states = [PDAState("q0"), PDAState("q1"), PDAState("q2")]
input_symbols = [0, 1]
stack_alphabet = [0, 1, "end"]
transition_function = []
transition_function.append(
PDATransitionFunction(states[0], 0, "end", states[0], [0, "end"]))
transition_function.append(
PDATransitionFunction(states[0], 1, "end", states[0], [1, "end"]))
transition_function.append(
PDATransitionFunction(states[0], 0, 0, states[0], [0, 0]))
transition_function.append(
PDATransitionFunction(states[0], 0, 1, states[0], [0, 1]))
transition_function.append(
PDATransitionFunction(states[0], 1, 1, states[0], [1, 1]))
transition_function.append(
PDATransitionFunction(states[0], 1, 0, states[0], [1, 0]))
transition_function.append(
PDATransitionFunction(states[0], "epsilon", "end", states[1],
["end"]))
transition_function.append(
PDATransitionFunction(states[0], "epsilon", 0, states[1], [0]))
transition_function.append(
PDATransitionFunction(states[0], "epsilon", 1, states[1], [1]))
transition_function.append(
PDATransitionFunction(states[1], 0, 0, states[1], []))
transition_function.append(
PDATransitionFunction(states[1], 1, 1, states[1], []))
transition_function.append(
PDATransitionFunction(states[1], "epsilon", "end", states[2], []))
start_state = states[0]
start_symbol = "end"
final_states = [states[2]]
pda = PDA(states, input_symbols, stack_alphabet, transition_function,
start_state, start_symbol, final_states)
pda = pda.from_empty_stack_to_final_state()
self.assertIsInstance(pda, PDA)
self.assertTrue(pda.accepts_by_final_state([0, 0, 1, 1, 0, 0], 100))
self.assertTrue(pda.accepts_by_final_state([0, 1, 1, 0], 100))
self.assertTrue(pda.accepts_by_final_state([1, 1], 100))
self.assertTrue(pda.accepts_by_final_state([], 100))
self.assertFalse(pda.accepts_by_final_state([0, 1, 0, 0], 1000))
self.assertFalse(pda.accepts_by_final_state([0, 0, 1, 0], 1000))
def from_empty_stack_to_final_state(self):
states = self.states[:]
start_state = PDAState("p_start_e_to_f")
final_states = [PDAState("p_final_e_to_f")]
states.append(start_state)
states.append(final_states[0])
stack_alphabet = self.stack_alphabet[:]
input_symbols = self.input_symbols[:]
start_symbol = Terminal("X_start_end_e_to_f")
stack_alphabet.append(start_symbol)
transition_function = self.transition_function[:]
transition_function.append(
PDATransitionFunction(start_state, "epsilon", start_symbol,
self.start_state,
[self.start_symbol, start_symbol]))
for q in self.states:
transition_function.append(
PDATransitionFunction(q, "epsilon", start_symbol,
final_states[0], []))
return PDA(states, input_symbols, stack_alphabet, transition_function,
start_state, start_symbol, final_states)
def test_to_pda(self):
cfg = CFG([Variable("E"), Variable("I")], [
Terminal("a"),
Terminal("b"),
Terminal("0"),
Terminal("1"),
Terminal("+"),
Terminal("*"),
Terminal("("),
Terminal(")")
], [
CFGRule(Variable("I"), [Terminal("a")]),
CFGRule(Variable("I"), [Terminal("b")]),
CFGRule(Variable("I"),
[Variable("I"), Terminal("a")]),
CFGRule(Variable("I"),
[Variable("I"), Terminal("b")]),
CFGRule(Variable("I"),
[Variable("I"), Terminal("0")]),
CFGRule(Variable("I"),
[Variable("I"), Terminal("1")]),
CFGRule(Variable("E"), [Variable("I")]),
CFGRule(
Variable("E"),
[Variable("E"), Terminal("*"),
Variable("E")]),
CFGRule(
Variable("E"),
[Variable("E"), Terminal("+"),
Variable("E")]),
CFGRule(
Variable("E"),
[Terminal("("), Variable("E"),
Terminal(")")])
], Variable("E"))
pda = cfg.to_PDA()
self.assertIsInstance(pda, PDA)
self.assertIn(
PDATransitionFunction(PDAState("q"), "epsilon", Variable("I"),
PDAState("q"), [Terminal("a")]),
pda.transition_function)
self.assertIn(
PDATransitionFunction(PDAState("q"), "epsilon", Variable("I"),
PDAState("q"),
[Variable("I"), Terminal("0")]),
pda.transition_function)
self.assertIn(
PDATransitionFunction(PDAState("q"), "epsilon", Variable("E"),
PDAState("q"), [Variable("I")]),
pda.transition_function)
self.assertEqual(18, len(pda.transition_function))
self.assertTrue(pda.accepts_by_empty_stack([Terminal("a")], 100))
self.assertTrue(pda.accepts_by_empty_stack([Terminal("b")], 100))
self.assertFalse(
pda.accepts_by_empty_stack([Terminal(x) for x in "b0"], 100))
self.assertTrue(
pda.accepts_by_empty_stack([Terminal(x) for x in "b0"], 1000))
self.assertTrue(
pda.accepts_by_empty_stack([Terminal(x) for x in "b00"], 10000))