# mode: run

cdef class Spam:

    cdef int tons

    cdef void add_tons(self, int x):

        self.tons += x

    cdef void eat(self):

        self.tons = 0

    def lift(self):

        print self.tons

cdef class SubSpam(Spam):

    cdef void add_tons(self, int x):

        self.tons += 2 * x

def test_spam():

    """

    >>> test_spam()

    5

    0

    20

    5

    """

    cdef Spam s

    cdef SubSpam ss

    s = Spam()

    s.eat()

    s.add_tons(5)

    s.lift()

    ss = SubSpam()

    ss.eat()

    ss.lift()

    ss.add_tons(10)

    ss.lift()

    s.lift()

cdef class SpamDish:

    cdef int spam

    cdef void describe(self):

        print "This dish contains", self.spam, "tons of spam."

cdef class FancySpamDish(SpamDish):

    cdef int lettuce

    cdef void describe(self):

        print "This dish contains", self.spam, "tons of spam",

        print "and", self.lettuce, "milligrams of lettuce."

cdef void describe_dish(SpamDish d):

    d.describe()

def test_spam_dish():

    """

    >>> test_spam_dish()

    This dish contains 42 tons of spam.

    This dish contains 88 tons of spam and 5 milligrams of lettuce.

    """

    cdef SpamDish s

    cdef FancySpamDish ss

    s = SpamDish()

    s.spam = 42

    ss = FancySpamDish()

    ss.spam = 88

    ss.lettuce = 5

    describe_dish(s)

    describe_dish(ss)