stackiter

stackiter.py

#!/usr/bin/env python

from collections import deque

def stackiter(iterable):
    iterator = iter(iterable)
    stack = deque()
    while True:
        if stack:
            val = stack.pop()
        else:
            val = iterator.next()

        newval = yield val
        if newval:
            stack.append(newval)
            stack.append(val)


if __name__ == "__main__":
    # prints 10, 20, 30, 40, 50, 60
    testiter = stackiter([10,20,50,60])
    for item in testiter:
        if item == 20:
            testiter.send(40)
            testiter.send(30)
        print(item)