# 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 exhausteddef 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 3printinorder([[[[1,[2]]],3]]) # dittox = [0, 1, [2, [3]], [4,5], [[[6]]] ]printinorder(x) # 0 1 2 3 4 5 6 # fcmp lexicographically compares the fringes of two nested listsdef 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 equalprint fcmp(range(6), x)  # -1; 1st list ends earlyprint fcmp(x, range(6))  #  1; 2nd list ends earlyprint fcmp(range(8), x)  #  1; 2nd list ends earlyprint fcmp(x, range(8))  # -1; 1st list ends earlyprint fcmp([1,[[2],8]],           [[[1],2],8])  #  0print fcmp([1,[[3],8]],           [[[1],2],8])  #  1print fcmp([1,[[2],8]],           [[[1],2],9])  # -1 # end of example