def test__is_contradictory__defeasibly(self):
p = Program.parse("""
bird(X) <- chicken(X).
bird(X) <- penguin(X).
~flies(X) <- penguin(X).
chicken(tina).
penguin(tweety).
scared(tina).
flies(X) -< bird(X).
flies(X) -< chicken(X), scared(X).
nests_in_trees(X) -< flies(X).
~flies(X) -< chicken(X).
""")
i = Interpreter(p)
expected = True
result = bool(i.is_contradictory(RuleType.DEFEASIBLE))
assert_that(result).is_equal_to(expected)
def test__get_derivations__not_flies_tina__strictly(self):
p = Program.parse("""
bird(X) <- chicken(X).
bird(X) <- penguin(X).
~flies(X) <- penguin(X).
chicken(tina).
penguin(tweety).
scared(tina).
flies(X) -< bird(X).
flies(X) -< chicken(X), scared(X).
nests_in_trees(X) -< flies(X).
~flies(X) -< chicken(X).
""")
i = Interpreter(p)
expected = set()
result = i.get_derivations(Literal.parse('~flies(tina)'),
RuleType.STRICT)
assert_that(result).is_equal_to(expected)
def test__is_counter_argument_of__9(self):
p = Program.parse("""
bird(X) <- chicken(X).
bird(X) <- penguin(X).
~flies(X) <- penguin(X).
chicken(tina).
penguin(tweety).
scared(tina).
flies(X) -< bird(X).
flies(X) -< chicken(X), scared(X).
nests_in_trees(X) -< flies(X).
~flies(X) -< chicken(X).
""")
i = Interpreter(p)
d1 = Derivation([
Rule.parse('bird(tina) <- chicken(tina).'),
Rule.parse('chicken(tina).'),
], i)
s1 = d1.get_structure()
result = s1.is_counter_argument_of(s1, s1)
assert_that(result).is_false()
def test__get_derivations__2(self):
p = Program.parse("""
a <- b, c.
b <- d, e.
b <- c.
c <- f, g.
d <- h.
e.
f.
g.
h.
""")
i = Interpreter(p)
expected = {
Derivation(
[Rule.parse('c <- f, g.'),
Rule.parse('f.'),
Rule.parse('g.')], i)
}
result = i.get_derivations(Literal.parse('c'))
assert_that(result).is_equal_to(expected)
def test__get_structure__bird_tina__strict(self):
p = Program.parse("""
bird(X) <- chicken(X).
bird(X) <- penguin(X).
~flies(X) <- penguin(X).
chicken(tina).
penguin(tweety).
scared(tina).
flies(X) -< bird(X).
flies(X) -< chicken(X), scared(X).
nests_in_trees(X) -< flies(X).
~flies(X) -< chicken(X).
""")
i = Interpreter(p)
d = Derivation([
Rule.parse('bird(tina) <- chicken(tina).'),
Rule.parse('chicken(tina).')
], i)
expected = Structure(set(), Literal.parse('bird(tina)'), d)
result = d.get_structure()
assert_that(result).is_equal_to(expected)
assert_that(result.is_strict()).is_true()
def test__get_derivations__not_flies_tina__defeasibly(self):
p = Program.parse("""
bird(X) <- chicken(X).
bird(X) <- penguin(X).
~flies(X) <- penguin(X).
chicken(tina).
penguin(tweety).
scared(tina).
flies(X) -< bird(X).
flies(X) -< chicken(X), scared(X).
nests_in_trees(X) -< flies(X).
~flies(X) -< chicken(X).
""")
i = Interpreter(p)
expected = {
Derivation([
Rule.parse('~flies(tina) -< chicken(tina).'),
Rule.parse('chicken(tina).')
], i)
}
result = i.get_derivations(Literal.parse('~flies(tina)'),
RuleType.DEFEASIBLE)
assert_that(result).is_equal_to(expected)