Guido van Rossum | f4e13a4 | 2000-11-08 15:17:49 +0000 | [diff] [blame] | 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: |
Guido van Rossum | d42124c | 2001-03-22 13:36:39 +0000 | [diff] [blame] | 12 | co.back(x) |
Guido van Rossum | f4e13a4 | 2000-11-08 15:17:49 +0000 | [diff] [blame] | 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 |