def test_term_no_match_already_bound_var(self):
t1 = Term('actor', Term('alice'))
p1 = Term('actor', Var('?A'))
u = {u'?A': Term('bob')}
with self.assertRaises(ValueError):
p1.match(t1, u)
self.assertEqual(u, {u'?A': Term('bob')})
def test_match_all_with_unique_binding(self):
# Find all pairs of actors. Because the actors must be different, there are only 2 matches.
self.assertMatchAll([a(t('actor', t('?A'))),
a(t('actor', t('?B')))], [{
'?A': Term('alice'),
'?B': Term('bob')
}, {
'?A': Term('bob'),
'?B': Term('alice')
}])
# Find all pairs of drinks. Since there is only one, and we can't return (gin,gin),
# there will be no matches.
self.assertMatchAll([a(t('drink', t('?A'))),
a(t('drink', t('?B')))], [])
def word(self):
if self.scanner.on_type('variable'):
return self.var()
self.scanner.check_type('word', 'punct', 'operator')
constructor = self.scanner.token
self.scanner.scan()
return Term(constructor)
def test_term_match_bind_var(self):
t1 = Term('actor', Term('alice'))
p1 = Term('actor', Var('?A'))
e = {}
u = p1.match(t1, e)
self.assertEqual(u, {u'?A': Term('alice')})
self.assertEqual(e, {})
def term(self):
if self.scanner.on_type('variable'):
return self.var()
self.scanner.check_type('word')
constructor = self.scanner.token
self.scanner.scan()
subterms = []
if self.scanner.consume('('):
subterms.append(self.term())
while self.scanner.consume(','):
subterms.append(self.term())
self.scanner.expect(')')
return Term(constructor, *subterms)
def test_match_all(self):
# Find all actors who are Cody. Since there is no such actor, this will return no matches.
self.assertMatchAll([a(t('actor', t('cody')))], [])
# Find all actors who are Alice. This will return one match, but no bindings.
self.assertMatchAll([a(t('actor', t('alice')))], [{}])
# Find all drinks. This will return one match, with ?D bound to the result.
self.assertMatchAll(
[a(t("drink", t("?D")))],
[{
'?D': Term('gin')
}] # there was a match, in which ?D was bound
)
# Find all actors.
self.assertMatchAll([a(t('actor', t('?C')))], [{
'?C': Term('alice')
}, {
'?C': Term('bob')
}])
# Find all actors who are holding the revolver.
self.assertMatchAll(
[a(t('actor', t('?C'))),
a(t('holding', t('?C'), t('revolver')))], [{
'?C': t('bob')
}])
# Find all actors who are holding a weapon.
self.assertMatchAll([
a(t('actor', t('?C'))),
a(t('weapon', t('?W'))),
a(t('holding', t('?C'), t('?W')))
], [{
'?W': t('knife'),
'?C': t('alice')
}, {
'?W': t('revolver'),
'?C': t('bob')
}])
def t(s, *args):
if s.startswith('?'):
return Var(s)
else:
return Term(s, *args)
def test_term_subst(self):
t = Term('actor', Var('?A'))
r = t.subst({u'?A': Term('alice')})
self.assertEqual(r, Term('actor', Term('alice')))
def test_term_match_already_bound_var(self):
t1 = Term('actor', Term('alice'))
p1 = Term('actor', Var('?A'))
u = p1.match(t1, {u'?A': Term('alice')})
self.assertEqual(u, {u'?A': Term('alice')})
def test_term_no_match_ground(self):
t1 = Term('actor', Term('alice'))
p1 = Term('actor', Term('bob'))
with self.assertRaises(ValueError):
p1.match(t1, {})
def test_term_match_ground(self):
t1 = Term('actor', Term('alice'))
p1 = Term('actor', Term('alice'))
u = p1.match(t1, {})
self.assertEqual(u, {})
def test_term_basic_properties(self):
t1 = Term('alice')
t2 = Term('actor', t1)
v1 = Var('?A')
t3 = Term('actor', v1)
self.assertTrue(t1.is_atom())
self.assertFalse(t2.is_atom())
self.assertFalse(v1.is_atom())
self.assertFalse(t3.is_atom())
self.assertTrue(t1.is_ground())
self.assertTrue(t2.is_ground())
self.assertFalse(v1.is_ground())
self.assertFalse(t3.is_ground())
self.assertEqual(t2, Term('actor', Term('alice')))
