def test_intersection(self):
""" Tests the intersection with a regex """
regex = Regex("a*b*")
dfa = regex.to_epsilon_nfa()
symb_a = Symbol("a")
symb_b = Symbol("b")
self.assertTrue(dfa.accepts([symb_a, symb_a, symb_b, symb_b]))
self.assertFalse(dfa.accepts([symb_b, symb_b, symb_a]))
ter_a = Terminal("a")
ter_b = Terminal("b")
var_s = Variable("S")
productions = {
Production(var_s, [ter_a, var_s, ter_b]),
Production(var_s, [ter_b, var_s, ter_a]),
Production(var_s, [])
}
cfg = CFG(productions=productions, start_symbol=var_s)
self.assertTrue(cfg.contains([ter_a, ter_a, ter_b, ter_b]))
self.assertFalse(cfg.contains([ter_a, ter_a, ter_b]))
cfg_i = cfg.intersection(regex)
self.assertTrue(cfg_i.contains([ter_a, ter_a, ter_b, ter_b]))
self.assertFalse(cfg_i.contains([ter_a, ter_a, ter_b]))
self.assertTrue(cfg_i.contains([]))
cfg_i = cfg.intersection(dfa)
self.assertTrue(cfg_i.contains([ter_a, ter_a, ter_b, ter_b]))
self.assertFalse(cfg_i.contains([ter_a, ter_a, ter_b]))
self.assertTrue(cfg_i.contains([]))
def _test_profiling_intersection(self):
size = 50
states = [State(i) for i in range(size * 2 + 1)]
symb_a = Symbol("a")
symb_b = Symbol("b")
dfa = DeterministicFiniteAutomaton(states, {symb_a, symb_b},
start_state=states[0],
final_states={states[-1]})
for i in range(size):
dfa.add_transition(states[i], symb_a, states[i + 1])
for i in range(size, size * 2):
dfa.add_transition(states[i], symb_b, states[i + 1])
ter_a = Terminal("a")
ter_b = Terminal("b")
var_s = Variable("S")
var_s1 = Variable("S1")
var_l = Variable("L")
productions = [
Production(var_s, [var_l, var_s1]),
Production(var_l, [Epsilon()]),
Production(var_s1, [ter_a, var_s1, ter_b]),
Production(var_s1, [ter_b, var_s1, ter_a]),
Production(var_s1, [])
]
cfg = CFG(productions=productions, start_symbol=var_s)
cfg_i = cfg.intersection(dfa)
self.assertFalse(cfg_i.is_empty())
self.assertTrue(cfg_i.contains([ter_a] * size + [ter_b] * size))
self.assertFalse(cfg_i.contains([]))
def test_intersection_dfa2(self):
state0 = State(0)
symb_a = Symbol("a")
symb_b = Symbol("b")
dfa = DeterministicFiniteAutomaton({state0}, {symb_a, symb_b},
start_state=state0,
final_states={state0})
dfa.add_transition(state0, symb_a, state0)
dfa.add_transition(state0, symb_b, state0)
self.assertTrue(dfa.accepts([symb_a, symb_a, symb_b, symb_b]))
ter_a = Terminal("a")
ter_b = Terminal("b")
var_s = Variable("S")
var_s1 = Variable("S1")
var_l = Variable("L")
productions = {
Production(var_s, [var_l, var_s1]),
Production(var_l, [Epsilon()]),
Production(var_s1, [ter_a, var_s1, ter_b]),
Production(var_s1, [ter_b, var_s1, ter_a]),
Production(var_s1, [])
}
cfg = CFG(productions=productions, start_symbol=var_s)
self.assertTrue(cfg.contains([ter_a, ter_a, ter_b, ter_b]))
self.assertFalse(cfg.contains([ter_a, ter_a, ter_b]))
cfg_i = cfg.intersection(dfa)
self.assertFalse(cfg_i.is_empty())
self.assertTrue(cfg_i.contains([ter_a, ter_a, ter_b, ter_b]))
self.assertTrue(cfg_i.contains([]))
def test_intersection_with_epsilon(self):
state0 = State(0)
state1 = State(1)
symb_a = Symbol("a")
dfa = DeterministicFiniteAutomaton({state0, state1}, {symb_a},
start_state=state0,
final_states={state1})
dfa.add_transition(state0, symb_a, state1)
self.assertTrue(dfa.accepts([symb_a]))
ter_a = Terminal("a")
var_s = Variable("S")
var_l = Variable("L")
var_t = Variable("T")
productions = {
Production(var_s, [var_l, var_t]),
Production(var_l, [Epsilon()]),
Production(var_t, [ter_a])
}
cfg = CFG(productions=productions, start_symbol=var_s)
self.assertFalse(cfg.is_empty())
self.assertTrue(cfg.contains([ter_a]))
cfg_temp = cfg.to_pda().to_cfg()
self.assertFalse(cfg_temp.is_empty())
self.assertTrue(cfg_temp.contains([ter_a]))
cfg_temp = cfg.to_pda().to_final_state().to_empty_stack().to_cfg()
self.assertFalse(cfg_temp.is_empty())
self.assertTrue(cfg_temp.contains([ter_a]))
cfg_i = cfg.intersection(dfa)
self.assertFalse(cfg_i.is_empty())
