def test_heap_discard():
h1 = Heap()
h2 = h1.branch()
h3 = h2.branch()
h = h2.discard(h3)
assert h3.prev is h1
assert h3 is h
h0 = Heap()
v0 = h0.newvar()
h1 = h0.branch()
v1 = h1.newvar()
h2 = h1.branch()
v2 = h2.newvar()
h2.add_trail(v0)
v0.binding = 1
h2.add_trail(v1)
v1.binding = 2
h3 = h2.branch()
h3.add_trail(v2)
v2.binding = 3
h = h2.discard(h3)
assert h3.prev is h1
assert h3 is h
assert h3.revert_upto(h0)
assert v0.binding is None
assert v1.binding is None
assert v2.binding == 3 # not backtracked, because it goes away
def test_heap_discard_variable_shunting():
h0 = Heap()
v0 = h0.newvar()
h1 = h0.branch()
v1a = h1.newvar()
v1b = h1.newvar()
h2 = h1.branch()
v2 = h1.newvar()
h2.add_trail(v0)
v0.binding = 1
h2.add_trail(v1a)
v1a.binding = 2
h = h1.discard(h2)
assert h2.prev is h0
assert h2 is h
assert h1.discarded
assert h1.prev is h2
h2.add_trail(v1b)
v1b.binding = 3
assert h2.revert_upto(h0)
assert v0.binding is None
assert v1a.binding == 2 # not backtracked, because it goes away
assert v1b.binding == 3 # not backtracked, because it goes away
def test_heap():
h1 = Heap()
v1 = h1.newvar()
v2 = h1.newvar()
h1.add_trail(v1)
v1.binding = 1
h2 = h1.branch()
h2.add_trail(v1)
v1.binding = 2
h2.add_trail(v2)
v2.binding = 3
h3 = h2.revert_upto(h1)
assert v1.binding == 1
assert v2.binding is None
assert h3 is h2
h1 = Heap()
h2 = h1.revert_upto(h1)
assert h2 is h1
h1 = Heap()
h2 = h1.branch()
h3 = h2.revert_upto(h1, discard_choicepoint=True)
assert h3 is h1
def test_heap_dont_trail_new():
h1 = Heap()
v1 = h1.newvar()
h1.add_trail(v1)
v1.binding = 1
h2 = h1.branch()
v2 = h2.newvar()
h2.add_trail(v1)
v1.binding = 2
h2.add_trail(v2)
v2.binding = 3
h3 = h2.revert_upto(h1)
assert v1.binding == 1
assert v2.binding == 3 # wasn't undone, because v2 dies
assert h3 is h2
def test_current_output():
e = Engine()
h = Heap()
X = h.newvar()
impl_current_output(e, h, X)
assert X.dereference(h).name() == e.streamwrapper.current_outstream.alias
def test_current_output():
e = Engine()
h = Heap()
X = h.newvar()
impl_current_output(e, h, X)
assert X.dereference(h).name() == e.streamwrapper.current_outstream.alias