def test_frame_discard():
eq = Predicate.from_name_arity('=', 2)
X = Term()
with Frame(discard=True):
X.put_integer(1)
assert_equal(str(X), '1')
assert_equal(str(X), '1')
X = Term()
with Frame(discard=True):
eq(X, Term.from_integer(1))
assert_equal(str(X), '1')
assert_equal(X.type(), 'integer')
assert_not_equal(str(X), '1')
assert_equal(X.type(), 'variable')
def test_frame_rewind():
X = Term()
with Frame() as f:
t = f.term()
t.put_integer(1)
X.unify_integer(2)
assert_equal(t, Term.from_integer(1))
assert_equal(X, Term.from_integer(2))
f.rewind()
with assert_raises(AttributeError):
str(t)
assert_equal(X.type(), 'variable')
X.unify_integer(3)
assert_equal(X, Term.from_integer(3))
f.rewind()
assert_equal(X.type(), 'variable')
X.unify_integer(2)
assert_equal(X, Term.from_integer(2))
