Example #1
0
    def test_simpleChainingTestShouldNotChange(self):
        g = Grammar(terminals=[0, 1],
                    nonterminals=[S, A, B, C],
                    rules=[Rules],
                    start_symbol=S)
        ContextFree.remove_rules_with_epsilon(g)
        self.assertEqual(len(g.rules()), 8)

        class RuleNewSto0(Rule):
            rule = ([S], [0])

        class RuleNewSto1(Rule):
            rule = ([S], [1])

        class RuleNewStoC(Rule):
            rule = ([S], [C])

        class RuleNewStoEPS(Rule):
            rule = ([S], [EPS])

        self.assertFalse(g.have_rule(RuleNewSto0))
        self.assertFalse(g.have_rule(RuleNewSto1))
        self.assertFalse(g.have_rule(RuleNewStoC))
        self.assertFalse(g.have_rule(RuleNewStoEPS))

        class RuleOldBtoEps(Rule):
            rule = ([B], [EPS])

        self.assertTrue(g.have_rule(RuleOldBtoEps))
Example #2
0
 def test_simpleTestShouldChange(self):
     g = Grammar(terminals=[1],
                 nonterminals=[S, A, B, C],
                 rules=[Rules],
                 start_symbol=S)
     ContextFree.remove_rules_with_epsilon(g, transform_grammar=True)
     self.assertEqual(g.rules_count(), 6)
     class RuleNewS(Rule): rule=([S], [1])
     class RuleNewA(Rule): rule=([A], [1])
     self.assertTrue(g.have_rule(RuleNewS))
     self.assertTrue(g.have_rule(RuleNewA))
     fromS = g.get_rule(RuleNewS)
     self.assertEqual(fromS.fromSymbol, S)
     self.assertEqual(fromS.toSymbol, 1)
     self.assertTrue(isclass(fromS))
     self.assertTrue(issubclass(fromS, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromS.from_rule.rule, ([S], [1, B]))
     self.assertEqual(fromS.replace_index, 1)
     fromA = g.get_rule(RuleNewA)
     self.assertEqual(fromA.fromSymbol, A)
     self.assertEqual(fromA.toSymbol, 1)
     self.assertTrue(isclass(fromA))
     self.assertTrue(issubclass(fromA, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromA.from_rule.rule, ([A], [1, B]))
     self.assertEqual(fromA.replace_index, 1)
     class OldA(Rule): rule=([A], [EPS])
     class OldB(Rule): rule=([B], [EPS])
     self.assertFalse(g.have_rule(OldA))
     self.assertFalse(g.have_rule(OldB))
 def setUp(self):
     self.g = Grammar(terminals=[My],
                      nonterminals=[S],
                      rules=[R],
                      start_symbol=S)
     ContextFree.remove_useless_symbols(self.g, transform_grammar=True)
     ContextFree.remove_rules_with_epsilon(self.g, transform_grammar=True)
     ContextFree.remove_unit_rules(self.g, transform_grammar=True)
     ContextFree.remove_useless_symbols(self.g, transform_grammar=True)
     ContextFree.transform_to_chomsky_normal_form(self.g, transform_grammar=True)
Example #4
0
 def test_simpleTestShouldNotChange(self):
     g = Grammar(terminals=[1],
                 nonterminals=[S, A, B, C],
                 rules=[Rules])
     ContextFree.remove_rules_with_epsilon(g)
     self.assertEqual(g.rules_count(), 6)
     class RuleNewS(Rule): rule=([S], [1])
     class RuleNewA(Rule): rule=([A], [1])
     self.assertFalse(g.have_rule(RuleNewS))
     self.assertFalse(g.have_rule(RuleNewA))
     class OldA(Rule): rule=([A], [EPS])
     class OldB(Rule): rule=([B], [EPS])
     self.assertTrue(g.have_rule(OldA))
     self.assertTrue(g.have_rule(OldB))
Example #5
0
    def test_simpleChainingTestShouldChange(self):
        g = Grammar(terminals=[0, 1],
                    nonterminals=[S, A, B, C],
                    rules=[Rules],
                    start_symbol=S)
        ContextFree.remove_rules_with_epsilon(g, transform_grammar=True)
        self.assertEqual(len(g.rules()), 11)

        class RuleNewSto0(Rule):
            rule = ([S], [0])

        class RuleNewSto1(Rule):
            rule = ([S], [1])

        class RuleNewStoC(Rule):
            rule = ([S], [C])

        class RuleNewStoEPS(Rule):
            rule = ([S], [EPS])

        self.assertTrue(
            g.have_rule([RuleNewSto0, RuleNewSto1, RuleNewStoC,
                         RuleNewStoEPS]))
        fromSto0 = g.get_rule(RuleNewSto0)
        self.assertTrue(isclass(fromSto0))
        self.assertTrue(issubclass(fromSto0, ContextFree.EpsilonRemovedRule))
        self.assertEqual(fromSto0.from_rule.rule, ([S], [0, A]))
        self.assertEqual(fromSto0.replace_index, 1)
        fromSto1 = g.get_rule(RuleNewSto1)
        self.assertTrue(isclass(fromSto1))
        self.assertTrue(issubclass(fromSto1, ContextFree.EpsilonRemovedRule))
        self.assertEqual(fromSto1.from_rule.rule, ([S], [1, C]))
        self.assertEqual(fromSto1.replace_index, 1)
        fromStoC = g.get_rule(RuleNewStoC)
        self.assertTrue(isclass(fromStoC))
        self.assertTrue(issubclass(fromStoC, ContextFree.EpsilonRemovedRule))
        self.assertEqual(fromStoC.from_rule.rule, ([S], [C, C]))
        self.assertEqual(fromStoC.replace_index, 0)
        fromStoEPS = g.get_rule(RuleNewStoEPS)
        self.assertTrue(isclass(fromStoEPS))
        self.assertTrue(issubclass(fromStoEPS, ContextFree.EpsilonRemovedRule))
        self.assertEqual(fromStoEPS.from_rule.rule, ([S], [C]))
        self.assertEqual(fromStoEPS.replace_index, 0)

        class RuleOldBtoEps(Rule):
            rule = ([B], [EPS])

        self.assertFalse(g.have_rule(RuleOldBtoEps))
Example #6
0
 def test_simpleTest(self):
     g = Grammar(terminals=[1],
                 nonterminals=[S, A, B, C],
                 rules=[Rules])
     com = ContextFree.remove_rules_with_epsilon(g)
     self.assertEqual(com.rules_count(), 6)
     class RuleNewS(Rule): rule=([S], [1])
     class RuleNewA(Rule): rule=([A], [1])
     self.assertTrue(com.have_rule(RuleNewS))
     self.assertTrue(com.have_rule(RuleNewA))
     fromS = com.get_rule(RuleNewS)
     self.assertEqual(fromS.fromSymbol, S)
     self.assertEqual(fromS.toSymbol, 1)
     self.assertTrue(isclass(fromS))
     self.assertTrue(issubclass(fromS, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromS.from_rule.rule, ([S], [1, B]))
     self.assertEqual(fromS.replace_index, 1)
     fromA = com.get_rule(RuleNewA)
     self.assertEqual(fromA.fromSymbol, A)
     self.assertEqual(fromA.toSymbol, 1)
     self.assertTrue(isclass(fromA))
     self.assertTrue(issubclass(fromA, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromA.from_rule.rule, ([A], [1, B]))
     self.assertEqual(fromA.replace_index, 1)
     class OldA(Rule): rule=([A], [EPS])
     class OldB(Rule): rule=([B], [EPS])
     self.assertFalse(com.have_rule(OldA))
     self.assertFalse(com.have_rule(OldB))
 def test_multipleUsageShouldNotChange(self):
     g = Grammar(terminals=[0, 1, 2, 3],
                 nonterminals=[S, A, B, C, D],
                 rules=[Rules],
                 start_symbol=S)
     ContextFree.remove_rules_with_epsilon(g)
     self.assertEqual(len(g.rules()), 12)
     self.assertEqual(g.rules_count(), 12)
     class RuleNewAto0A(Rule): rule = ([A], [0, A])
     class RuleNewAtoA0(Rule): rule = ([A], [A, 0])
     class RuleNewAtoB(Rule): rule = ([A], [B])
     class RuleNewAtoC(Rule): rule = ([A], [C])
     class RuleNewAtoCC(Rule): rule = ([A], [C, C])
     class RuleNewAto1(Rule): rule = ([A], [1])
     class RuleNewBto3(Rule): rule = ([B], [3])
     class RuleNewCtoA3(Rule): rule = ([C], [A, 3])
     class RuleNewDtoAB(Rule): rule = ([D], [A, B])
     class RuleNewDtoAA(Rule): rule = ([D], [A, A])
     class RuleNewDtoA3(Rule): rule = ([D], [A, 3])
     class RuleNewCto3(Rule): rule = ([C], [3])
     class RuleNewDtoA(Rule): rule = ([D], [A])
     class RuleNewDtoB(Rule): rule = ([D], [B])
     class RuleNewDto3(Rule): rule = ([D], [3])
     self.assertFalse(g.have_rule(RuleNewAto0A))
     self.assertFalse(g.have_rule(RuleNewAtoA0))
     self.assertFalse(g.have_rule(RuleNewAtoB))
     self.assertFalse(g.have_rule(RuleNewAtoC))
     self.assertFalse(g.have_rule(RuleNewAtoCC))
     self.assertFalse(g.have_rule(RuleNewAto1))
     self.assertFalse(g.have_rule(RuleNewBto3))
     self.assertFalse(g.have_rule(RuleNewCtoA3))
     self.assertFalse(g.have_rule(RuleNewDtoAB))
     self.assertFalse(g.have_rule(RuleNewDtoAA))
     self.assertFalse(g.have_rule(RuleNewDtoA3))
     self.assertFalse(g.have_rule(RuleNewCto3))
     self.assertFalse(g.have_rule(RuleNewDtoA))
     self.assertFalse(g.have_rule(RuleNewDtoB))
     self.assertFalse(g.have_rule(RuleNewDto3))
     class BtoEps(Rule): rule=([B], [EPS])
     class CtoEps(Rule): rule=([B], [EPS])
     self.assertTrue(g.have_rule(BtoEps))
     self.assertTrue(g.have_rule(CtoEps))
Example #8
0
 def test_simpleTestOverUnitRule(self):
     g = Grammar(
         terminals=[0, 1, 2, 3],
         nonterminals=[S, A, B, C],
         rules=[RuleS0A, RuleAB, RuleAEps, RuleBEps, RuleB1C, RuleC11],
         start_symbol=S)
     gr = ContextFree.transform_to_chomsky_normal_form(
         ContextFree.remove_unit_rules(
             ContextFree.remove_rules_with_epsilon(g)))
     pars = cyk(gr, [0])
     s = InverseContextFree.epsilon_rules_restore(
         InverseContextFree.unit_rules_restore(
             InverseContextFree.transform_from_chomsky_normal_form(pars)))
     self.assertIsInstance(s, S)
     self.assertIsInstance(s.to_rule, RuleS0A)
     self.assertIsInstance(s.to_rule.to_symbols[0], Terminal)
     self.assertEqual(s.to_rule.to_symbols[0].s, 0)
     a = s.to_rule.to_symbols[1]
     self.assertIsInstance(a, A)
     self.assertIsInstance(a.to_rule, RuleAEps)
     self.assertIs(a.to_rule.to_symbols[0].s, EPS)
 def test_multipleUsage(self):
     g = Grammar(terminals=[0, 1, 2, 3],
                 nonterminals=[S, A, B, C, D],
                 rules=[Rules],
                 start_symbol=S)
     com = ContextFree.remove_rules_with_epsilon(g)
     self.assertEqual(len(com.rules()), 25)
     self.assertEqual(com.rules_count(), 25)
     class RuleNewSto0A(Rule): rule = ([S], [0, A])
     self.assertTrue(com.have_rule(RuleNewSto0A))
     fromSto0A = com.get_rule(RuleNewSto0A)
     self.assertTrue(isclass(fromSto0A))
     self.assertTrue(issubclass(fromSto0A, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromSto0A.from_rule.rule, ([S], [A, 0, A]))
     self.assertEqual(fromSto0A.replace_index, 0)
     class RuleNewStoA0(Rule): rule = ([S], [A, 0])
     self.assertTrue(com.have_rule(RuleNewStoA0))
     fromStoA0 = com.get_rule(RuleNewStoA0)
     self.assertTrue(isclass(fromStoA0))
     self.assertTrue(issubclass(fromStoA0, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromStoA0.from_rule.rule, ([S], [A, 0, A]))
     self.assertEqual(fromStoA0.replace_index, 2)
     class RuleNewAtoB(Rule): rule = ([A], [B])
     self.assertTrue(com.have_rule(RuleNewAtoB))
     fromAtoB = com.get_rule(RuleNewAtoB)
     self.assertTrue(isclass(fromAtoB))
     self.assertTrue(issubclass(fromAtoB, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromAtoB.from_rule.rule, ([A], [B, C]))
     self.assertEqual(fromAtoB.replace_index, 1)
     class RuleNewAtoC(Rule): rule = ([A], [C])
     self.assertTrue(com.have_rule(RuleNewAtoC))
     fromAtoC = com.get_rule(RuleNewAtoC)
     self.assertTrue(isclass(fromAtoC))
     self.assertTrue(issubclass(fromAtoC, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromAtoC.from_rule.rule, ([A], [B, C]))
     self.assertEqual(fromAtoC.replace_index, 0)
     class RuleNewAtoCC(Rule): rule = ([A], [C, C])
     self.assertTrue(com.have_rule(RuleNewAtoCC))
     fromAtoCC = com.get_rule(RuleNewAtoCC)
     self.assertTrue(isclass(fromAtoCC))
     self.assertTrue(issubclass(fromAtoCC, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromAtoCC.from_rule.rule, ([A], [C, C, C]))
     self.assertEqual(fromAtoCC.replace_index, 0)
     class RuleNewBto1(Rule): rule = ([B], [1])
     self.assertTrue(com.have_rule(RuleNewBto1))
     fromBto1 = com.get_rule(RuleNewBto1)
     self.assertTrue(isclass(fromBto1))
     self.assertTrue(issubclass(fromBto1, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromBto1.from_rule.rule, ([B], [1, C]))
     self.assertEqual(fromBto1.replace_index, 1)
     class RuleNewBto3(Rule): rule = ([B], [3])
     self.assertTrue(com.have_rule(RuleNewBto3))
     fromBto3 = com.get_rule(RuleNewBto3)
     self.assertTrue(isclass(fromBto3))
     self.assertTrue(issubclass(fromBto3, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromBto3.from_rule.rule, ([B], [3, D]))
     self.assertEqual(fromBto3.replace_index, 1)
     class RuleNewCtoA3(Rule): rule = ([C], [A, 3])
     self.assertTrue(com.have_rule(RuleNewCtoA3))
     fromCtoA3 = com.get_rule(RuleNewCtoA3)
     self.assertTrue(isclass(fromCtoA3))
     self.assertTrue(issubclass(fromCtoA3, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromCtoA3.from_rule.rule, ([C], [A, A, 3]))
     self.assertEqual(fromCtoA3.replace_index, 0)
     class RuleNewDtoAB(Rule): rule = ([D], [A, B])
     self.assertTrue(com.have_rule(RuleNewDtoAB))
     fromDtoAB = com.get_rule(RuleNewDtoAB)
     self.assertTrue(isclass(fromDtoAB))
     self.assertTrue(issubclass(fromDtoAB, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromDtoAB.from_rule.rule, ([D], [A, A, B]))
     self.assertEqual(fromDtoAB.replace_index, 0)
     class RuleNewDtoAA(Rule): rule = ([D], [A, A])
     self.assertTrue(com.have_rule(RuleNewDtoAA))
     fromDtoAA = com.get_rule(RuleNewDtoAA)
     self.assertTrue(isclass(fromDtoAA))
     self.assertTrue(issubclass(fromDtoAA, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromDtoAA.from_rule.rule, ([D], [A, A, B]))
     self.assertEqual(fromDtoAA.replace_index, 2)
     class RuleNewDtoA3(Rule): rule = ([D], [A, 3])
     self.assertTrue(com.have_rule(RuleNewDtoA3))
     fromDtoA3 = com.get_rule(RuleNewDtoA3)
     self.assertTrue(isclass(fromDtoA3))
     self.assertTrue(issubclass(fromDtoA3, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromDtoA3.from_rule.rule, ([D], [A, A, 3]))
     self.assertEqual(fromDtoA3.replace_index, 0)
     class RuleNewCto3(Rule): rule = ([C], [3])
     self.assertTrue(com.have_rule(RuleNewCto3))
     fromCto3 = com.get_rule(RuleNewCto3)
     self.assertTrue(isclass(fromCto3))
     self.assertTrue(issubclass(fromCto3, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromCto3.from_rule.rule, ([C], [A, 3]))
     self.assertEqual(fromCto3.replace_index, 0)
     class RuleNewDtoA(Rule): rule = ([D], [A])
     self.assertTrue(com.have_rule(RuleNewDtoA))
     fromDtoA = com.get_rule(RuleNewDtoA)
     self.assertTrue(isclass(fromDtoA))
     self.assertTrue(issubclass(fromDtoA, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromDtoA.from_rule.rule, ([D], [A, B]))
     self.assertEqual(fromDtoA.replace_index, 1)
     class RuleNewDtoB(Rule): rule = ([D], [B])
     self.assertTrue(com.have_rule(RuleNewDtoB))
     fromDtoB = com.get_rule(RuleNewDtoB)
     self.assertTrue(isclass(fromDtoB))
     self.assertTrue(issubclass(fromDtoB, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromDtoB.from_rule.rule, ([D], [A, B]))
     self.assertEqual(fromDtoB.replace_index, 0)
     class RuleNewDto3(Rule): rule = ([D], [3])
     self.assertTrue(com.have_rule(RuleNewDto3))
     fromDto3 = com.get_rule(RuleNewDto3)
     self.assertTrue(isclass(fromDto3))
     self.assertTrue(issubclass(fromDto3, ContextFree.EpsilonRemovedRule))
     self.assertEqual(fromDto3.from_rule.rule, ([D], [A, 3]))
     self.assertEqual(fromDto3.replace_index, 0)
     class BtoEps(Rule): rule=([B], [EPS])
     class CtoEps(Rule): rule=([B], [EPS])
     self.assertFalse(com.have_rule(BtoEps))
     self.assertFalse(com.have_rule(CtoEps))
    def test_simpleChainingTest(self):
        g = Grammar(terminals=[0, 1],
                    nonterminals=[S, A, B, C],
                    rules=[Rules],
                    start_symbol=S)
        com = ContextFree.remove_rules_with_epsilon(g)
        self.assertEqual(len(com.rules()), 12)

        class RuleNewStoBC(Rule):
            rule = ([S], [B, C])

        class RuleNewStoAC(Rule):
            rule = ([S], [A, C])

        class RuleNewStoAB(Rule):
            rule = ([S], [A, B])

        class RuleNewAto0(Rule):
            rule = ([A], [0])

        class RuleNewStoB(Rule):
            rule = ([S], [B])

        class RuleNewStoC(Rule):
            rule = ([S], [C])

        class RuleNewStoA(Rule):
            rule = ([S], [A])

        class RuleNewStoEPS(Rule):
            rule = ([S], [EPS])

        self.assertTrue(
            com.have_rule([
                RuleNewStoBC, RuleNewStoAC, RuleNewStoAB, RuleNewAto0,
                RuleNewStoB, RuleNewStoC, RuleNewStoA, RuleNewStoEPS
            ]))
        fromStoBC = com.get_rule(RuleNewStoBC)
        self.assertTrue(isclass(fromStoBC))
        self.assertTrue(issubclass(fromStoBC, ContextFree.EpsilonRemovedRule))
        self.assertEqual(fromStoBC.from_rule.rule, ([S], [A, B, C]))
        self.assertEqual(fromStoBC.replace_index, 0)
        fromStoAC = com.get_rule(RuleNewStoAC)
        self.assertTrue(isclass(fromStoAC))
        self.assertTrue(issubclass(fromStoAC, ContextFree.EpsilonRemovedRule))
        self.assertEqual(fromStoAC.from_rule.rule, ([S], [A, B, C]))
        self.assertEqual(fromStoAC.replace_index, 1)
        fromStoAB = com.get_rule(RuleNewStoAB)
        self.assertTrue(isclass(fromStoAB))
        self.assertTrue(issubclass(fromStoAB, ContextFree.EpsilonRemovedRule))
        self.assertEqual(fromStoAB.from_rule.rule, ([S], [A, B, C]))
        self.assertEqual(fromStoAB.replace_index, 2)
        fromAto0 = com.get_rule(RuleNewAto0)
        self.assertTrue(isclass(fromAto0))
        self.assertTrue(issubclass(fromAto0, ContextFree.EpsilonRemovedRule))
        self.assertEqual(fromAto0.from_rule.rule, ([A], [0, A]))
        self.assertEqual(fromAto0.replace_index, 1)
        fromStoA = com.get_rule(RuleNewStoA)
        self.assertTrue(isclass(fromStoA))
        self.assertTrue(issubclass(fromStoA, ContextFree.EpsilonRemovedRule))
        self.assertEqual(fromStoA.from_rule.rule, ([S], [A, C]))
        self.assertEqual(fromStoA.replace_index, 1)
        fromStoB = com.get_rule(RuleNewStoB)
        self.assertTrue(isclass(fromStoB))
        self.assertTrue(issubclass(fromStoB, ContextFree.EpsilonRemovedRule))
        self.assertEqual(fromStoB.from_rule.rule, ([S], [B, C]))
        self.assertEqual(fromStoB.replace_index, 1)
        fromStoC = com.get_rule(RuleNewStoC)
        self.assertTrue(isclass(fromStoC))
        self.assertTrue(issubclass(fromStoC, ContextFree.EpsilonRemovedRule))
        self.assertEqual(fromStoC.from_rule.rule, ([S], [B, C]))
        self.assertEqual(fromStoC.replace_index, 0)
        fromStoEPS = com.get_rule(RuleNewStoEPS)
        self.assertTrue(isclass(fromStoEPS))
        self.assertTrue(issubclass(fromStoEPS, ContextFree.EpsilonRemovedRule))
        self.assertEqual(fromStoEPS.from_rule.rule, ([S], [C]))
        self.assertEqual(fromStoEPS.replace_index, 0)

        class RuleOldAtoEps(Rule):
            rule = ([A], [EPS])

        class RuleOldBtoEps(Rule):
            rule = ([B], [EPS])

        class RuleOldCtoEps(Rule):
            rule = ([C], [EPS])

        self.assertFalse(com.have_rule(RuleOldAtoEps))
        self.assertFalse(com.have_rule(RuleOldBtoEps))
        self.assertFalse(com.have_rule(RuleOldCtoEps))
Example #11
0
 def test_simpleTestOverUnitRule(self):
     g = Grammar(terminals=[0, 1],
                 nonterminals=[S, A, B, C, D],
                 rules=[RuleS1AB, RuleB0, RuleACD, RuleCD, RuleDEps],
                 start_symbol=S)
     gr = ContextFree.transform_to_chomsky_normal_form(ContextFree.remove_unit_rules(ContextFree.remove_rules_with_epsilon(g)))
     pars = cyk(gr, [1, 0])
     s = InverseContextFree.epsilon_rules_restore(InverseContextFree.unit_rules_restore(InverseContextFree.transform_from_chomsky_normal_form(pars)))
     self.assertIsInstance(s, S)
     self.assertIsInstance(s.to_rule, RuleS1AB)
     self.assertIsInstance(s.to_rule.to_symbols[0], Terminal)
     self.assertEqual(s.to_rule.to_symbols[0].s, 1)
     b = s.to_rule.to_symbols[2]
     self.assertIsInstance(b, B)
     self.assertIsInstance(b.to_rule, RuleB0)
     self.assertIsInstance(b.to_rule.to_symbols[0], Terminal)
     self.assertEqual(b.to_rule.to_symbols[0].s, 0)
     a = s.to_rule.to_symbols[1]
     self.assertIsInstance(a, A)
     self.assertIsInstance(a.to_rule, RuleACD)
     d = a.to_rule.to_symbols[1]
     self.assertIsInstance(d, D)
     self.assertIsInstance(d.to_rule, RuleDEps)
     self.assertIs(d.to_rule.to_symbols[0].s, EPS)
     c = a.to_rule.to_symbols[0]
     self.assertIsInstance(c, C)
     self.assertIsInstance(c.to_rule, RuleCD)
     d = c.to_rule.to_symbols[0]
     self.assertIsInstance(d, D)
     self.assertIsInstance(d.to_rule, RuleDEps)
     self.assertIs(d.to_rule.to_symbols[0].s, EPS)