/Demo/threads/fcmp.py

 1# Coroutine example:  controlling multiple instances of a single function
 2
 3from Coroutine import *
 4
 5# fringe visits a nested list in inorder, and detaches for each non-list
 6# element; raises EarlyExit after the list is exhausted
 7def fringe(co, list):
 8    for x in list:
 9        if type(x) is type([]):
10            fringe(co, x)
11        else:
12            co.back(x)
13
14def printinorder(list):
15    co = Coroutine()
16    f = co.create(fringe, co, list)
17    try:
18        while 1:
19            print co.tran(f),
20    except EarlyExit:
21        pass
22    print
23
24printinorder([1,2,3])  # 1 2 3
25printinorder([[[[1,[2]]],3]]) # ditto
26x = [0, 1, [2, [3]], [4,5], [[[6]]] ]
27printinorder(x) # 0 1 2 3 4 5 6
28
29# fcmp lexicographically compares the fringes of two nested lists
30def fcmp(l1, l2):
31    co1 = Coroutine(); f1 = co1.create(fringe, co1, l1)
32    co2 = Coroutine(); f2 = co2.create(fringe, co2, l2)
33    while 1:
34        try:
35            v1 = co1.tran(f1)
36        except EarlyExit:
37            try:
38                v2 = co2.tran(f2)
39            except EarlyExit:
40                return 0
41            co2.kill()
42            return -1
43        try:
44            v2 = co2.tran(f2)
45        except EarlyExit:
46            co1.kill()
47            return 1
48        if v1 != v2:
49            co1.kill(); co2.kill()
50            return cmp(v1,v2)
51
52print fcmp(range(7), x)  #  0; fringes are equal
53print fcmp(range(6), x)  # -1; 1st list ends early
54print fcmp(x, range(6))  #  1; 2nd list ends early
55print fcmp(range(8), x)  #  1; 2nd list ends early
56print fcmp(x, range(8))  # -1; 1st list ends early
57print fcmp([1,[[2],8]],
58           [[[1],2],8])  #  0
59print fcmp([1,[[3],8]],
60           [[[1],2],8])  #  1
61print fcmp([1,[[2],8]],
62           [[[1],2],9])  # -1
63
64# end of example