# Coroutine example:  controlling multiple instances of a single function

from Coroutine import *

# fringe visits a nested list in inorder, and detaches for each non-list

# element; raises EarlyExit after the list is exhausted

def fringe(co, list):

    for x in list:

        if type(x) is type([]):

            fringe(co, x)

        else:

            co.back(x)

def printinorder(list):

    co = Coroutine()

    f = co.create(fringe, co, list)

    try:

        while 1:

            print co.tran(f),

    except EarlyExit:

        pass

    print

printinorder([1,2,3])  # 1 2 3

printinorder([[[[1,[2]]],3]]) # ditto

x = [0, 1, [2, [3]], [4,5], [[[6]]] ]

printinorder(x) # 0 1 2 3 4 5 6

# fcmp lexicographically compares the fringes of two nested lists

def fcmp(l1, l2):

    co1 = Coroutine(); f1 = co1.create(fringe, co1, l1)

    co2 = Coroutine(); f2 = co2.create(fringe, co2, l2)

    while 1:

        try:

            v1 = co1.tran(f1)

        except EarlyExit:

            try:

                v2 = co2.tran(f2)

            except EarlyExit:

                return 0

            co2.kill()

            return -1

        try:

            v2 = co2.tran(f2)

        except EarlyExit:

            co1.kill()

            return 1

        if v1 != v2:

            co1.kill(); co2.kill()

            return cmp(v1,v2)

print fcmp(range(7), x)  #  0; fringes are equal

print fcmp(range(6), x)  # -1; 1st list ends early

print fcmp(x, range(6))  #  1; 2nd list ends early

print fcmp(range(8), x)  #  1; 2nd list ends early

print fcmp(x, range(8))  # -1; 1st list ends early

print fcmp([1,[[2],8]],

           [[[1],2],8])  #  0

print fcmp([1,[[3],8]],

           [[[1],2],8])  #  1

print fcmp([1,[[2],8]],

           [[[1],2],9])  # -1

# end of example