def test__is_subargument_of__min_min(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 = Structure(set(), Literal.parse('bird(tina)'), d1)
d2 = Derivation([
Rule.parse('flies(tina) -< bird(tina).'),
Rule.parse('bird(tina) <- chicken(tina).'),
Rule.parse('chicken(tina).'),
], i)
s2 = Structure({Rule.parse('flies(tina) -< bird(tina).')},
Literal.parse('flies(tina)'), d2)
expected = True
result = s1.is_subargument_of(s1)
assert_that(result).is_equal_to(expected)
def test__disagreement__2(self):
literal1 = Literal.parse('a')
literal2 = Literal.parse('c')
program = Program.parse('~h <- b. h <- a.')
result = disagree(literal1, literal2, program.rules)
assert_that(result).is_false()
def disagree(literal1: Literal, literal2: Literal,
rules: Iterable[Rule]) -> bool:
if literal1.get_complement() == literal2:
return True
index = as_index(rules, RuleType.STRICT)
index.setdefault(literal1, set()).add(literal1.as_fact())
index.setdefault(literal2, set()).add(literal2.as_fact())
return bool(is_contradictory(index))
def test__get_structure__flies_tina_2__not_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('flies(tina) -< chicken(tina), scared(tina).'),
Rule.parse('chicken(tina).'),
Rule.parse('scared(tina).'),
], i)
expected = Structure(
{Rule.parse('flies(tina) -< chicken(tina), scared(tina).')},
Literal.parse('flies(tina)'), d)
result = d.get_structure()
assert_that(result).is_equal_to(expected)
assert_that(result.is_strict()).is_false()
def query(
self,
literal: Literal,
mode: RuleType = RuleType.DEFEASIBLE
) -> Tuple[Answer, Optional[Warrant]]:
if self._answers is None:
self._answers = {}
answers = self._answers.setdefault(mode, {})
if literal not in answers:
if literal not in self.get_literals(mode):
answers.setdefault(literal, (Answer.UNKNOWN, None))
else:
warrant = self._get_warrant(literal, mode)
if warrant is not None:
answers.setdefault(literal, (Answer.YES, warrant))
else:
complement = literal.get_complement()
warrant = self._get_warrant(complement, mode)
if warrant is not None:
answers.setdefault(literal, (Answer.NO, warrant))
else:
answers.setdefault(literal, (Answer.UNDECIDED, None))
return self._answers.get(mode, {}).get(literal, (Answer.UNKNOWN, None))
def test__get_derivations__3(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('b <- c.'),
Rule.parse('c <- f, g.'),
Rule.parse('f.'),
Rule.parse('g.')
], i),
Derivation([
Rule.parse('b <- d, e.'),
Rule.parse('d <- h.'),
Rule.parse('h.'),
Rule.parse('e.')
], i),
}
result = i.get_derivations(Literal.parse('b'))
assert_that(result).is_equal_to(expected)
def test__get_derivations__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), scared(tina).'),
Rule.parse('chicken(tina).'),
Rule.parse('scared(tina).')
], i),
Derivation([
Rule.parse('flies(tina) -< bird(tina).'),
Rule.parse('bird(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)
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 visit_literal(self, node: Node, children: List) -> Literal:
try:
return Literal(children[0], children[1])
except IndexError:
return Literal(False, children[0])
def test__disagreement__0(self):
literal1 = Literal.parse('a')
literal2 = Literal.parse('~a')
result = disagree(literal1, literal2, {})
assert_that(result).is_true()