def membero(x, coll):
""" Goal such that x is an item of coll """
if not isvar(x) and not isvar(coll):
if x in coll:
return success
return (lany,) + tuple((eq, x, item) for item in coll)
if isvar(x) and not isvar(coll):
return (lany,) + tuple((eq, x, item) for item in coll)
raise EarlyGoalError()
def test_isvar():
assert not isvar(3)
assert isvar(var(3))
def test_context_manager():
with variables(1):
assert isvar(1)
assert not isvar(1)
