def evaluate(self, env):
ev1 = evaluate(self.v1, env)
ev2 = evaluate(self.v2, env)
if isinstance(ev1, str) or isinstance(ev2, str): # string comparison needs special-casing
if set([ev1, ev2]) == set(["", identifier("Null")]):
return True
return ev1 == ev2
def testResult(self):
self.assertEquals(["ab", "a", "b", identifier("Null")], list(self.pgm.execute()))