Demo/threads/fcmp.py

   1 # Coroutine example:  controlling multiple instances of a single function
   2
   3 from 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
   7 def 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
  14 def 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
  24 printinorder([1,2,3])  # 1 2 3
  25 printinorder([[[[1,[2]]],3]]) # ditto
  26 x = [0, 1, [2, [3]], [4,5], [[[6]]] ]
  27 printinorder(x) # 0 1 2 3 4 5 6
  28
  29 # fcmp lexicographically compares the fringes of two nested lists
  30 def 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
  52 print fcmp(range(7), x)  #  0; fringes are equal
  53 print fcmp(range(6), x)  # -1; 1st list ends early
  54 print fcmp(x, range(6))  #  1; 2nd list ends early
  55 print fcmp(range(8), x)  #  1; 2nd list ends early
  56 print fcmp(x, range(8))  # -1; 1st list ends early
  57 print fcmp([1,[[2],8]],
  58            [[[1],2],8])  #  0
  59 print fcmp([1,[[3],8]],
  60            [[[1],2],8])  #  1
  61 print fcmp([1,[[2],8]],
  62            [[[1],2],9])  # -1
  63
  64 # end of example