# 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