#
# An iterator class that uses ``yield``.
#   This iterator produces every other item in a sequence.
#
class YieldIteratorExample:
    def __init__(self, seq):
        self.seq = seq
        self.iterator = self._next()
        self.next = self.iterator.next
    def _next(self):
        flag = 0
        for x in self.seq:
            if flag:
                flag = 0
                yield x
            else:
                flag = 1
    def __iter__(self):
        return self.iterator
    def refresh(self):
        self.iterator = self._next()
        self.next = self.iterator.next


def test_yielditeratorexample():
    a = YieldIteratorExample('edcba')
    for x in a:
        print x
    print '----------'
    a.refresh()
    for x in a:
        print x
    print '=' * 30
    a = YieldIteratorExample('abcde')
    try:
        print a.next()
        print a.next()
        print a.next()
        print a.next()
        print a.next()
        print a.next()
    except StopIteration, e:
        print 'stopping', e

test_yielditeratorexample()