#!/usr/bin/env python3

from itertools import zip_longest

from itertools import repeat, chain

def zip_longest_doc(*args, fillvalue=None):
    # zip_longest('ABCD', 'xy', fillvalue='-') --> Ax By C- D-
    def sentinel(counter = ([fillvalue]*(len(args)-1)).pop):
        yield counter()         # yields the fillvalue, or raises IndexError
    fillers = repeat(fillvalue)
    iters = [chain(it, sentinel(), fillers) for it in args]
    try:
        for tup in zip(*iters):
            yield tup
    except IndexError:
        pass

class Repeater:
    def __init__(self, o, t):
        self.o = o
        self.t = int(t)
    def __iter__(self):
        return self
    def __next__(self):
        if self.t > 0:
            self.t -= 1
            return self.o
        else:
            raise StopIteration

r1 = Repeater(1, 3)
r2 = Repeater(2, 4)
print('zip_longest_doc:')
for i, j in zip_longest_doc(r1, r2, fillvalue=0):
    print(i, j)

r1 = Repeater(1, 3)
r2 = Repeater(2, 4)
print('zip_longest_doc + list():')
l = list(zip_longest_doc(r1, r2, fillvalue=0))
print(l)

r1 = Repeater(1, 3)
r2 = Repeater(2, 4)
print('zip_longest + list():')
l = list(zip_longest(r1, r2, fillvalue=0))
print(l)

r1 = Repeater(1, 3)
r2 = Repeater(2, 4)
print('zip_longest:')
for i, j in zip_longest(r1, r2, fillvalue=0):
    print(i, j)