def test_pop_double():
d = Derivation()
d.add("bbs", -1)
d.add("bSa", 2)
assert ("bSa", 2) == d.pop()
assert ("bbs", -1) == d.pop()
assert d.isEmpty()
def test_all_derivations_two():
cfg = ({"E"}, {"a", "b"}, {"E": ["E+E", "E*E", "(E)", "a", "b"]}, "E")
string = "a+b+a"
firstDerivation = Derivation(entries=[("E", 0), ("E+E", 0), ("E+E+E", 0), ("a+E+E", 2), ("a+b+E", 4), ("a+b+a", -1)])
secondDerivation = Derivation(entries=[("E", 0), ("E+E", 0), ("E+E+E", 0), ("a+E+E", 4), ("a+E+a", 2), ("a+b+a", -1)])
derivations = d.getAllDerivations(cfg, string, MAX_SUBSTITUTIONS=5, MAX_DERIVATIONS=36)
# for de in derivations: print str(de)
assert firstDerivation in derivations
assert secondDerivation in derivations
def test_simple_derivations():
cfg = (["S", "A"], ["a", "b"], {"S": ["aA"], "A": ["a", "b"]}, "S")
string = "aa"
firstDerivation = Derivation(entries=[("S", 0), ("aA", 1), ("aa", -1)])
derivations = d.getAllDerivations(cfg, string, MAX_SUBSTITUTIONS=5, MAX_DERIVATIONS=2)
for de in derivations: print str(de)
assert firstDerivation in derivations
def test_get_left_derivations():
cfg = ({"S", "A"}, {"a", "b"}, {"S": ["aAS", "a"], "A": ["SbA", "SS", "ba"]}, "S")
string = "aabbaa"
expected = Derivation(entries=[("S", 0), ("aAS", 1), ("aSbAS", 1), ("aabAS", 3), ("aabbaS", 5), ("aabbaa", -1)])
actual = d.getLeftDerivation(cfg, string)
print actual
print expected
assert expected == actual
def test_add():
d = Derivation()
d.add("AAs", 1)
def test_clear():
d = Derivation()
d.add("bbs", -1)
d.add("bSa", 2)
d.clear()
assert d.isEmpty()
def test_empty():
d = Derivation()
assert d.isEmpty()
def test_pop_simple():
d = Derivation()
d.add("bBs", 2)
d.pop()
assert d.isEmpty()
def test_add_no_variable():
d = Derivation()
d.add("aas", -1)