mirror of https://github.com/python/cpython
65 lines
1.7 KiB
Python
65 lines
1.7 KiB
Python
# Coroutine example: controlling multiple instances of a single function
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from Coroutine import *
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# fringe visits a nested list in inorder, and detaches for each non-list
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# element; raises EarlyExit after the list is exhausted
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def fringe(co, list):
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for x in list:
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if type(x) is type([]):
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fringe(co, x)
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else:
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co.back(x)
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def printinorder(list):
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co = Coroutine()
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f = co.create(fringe, co, list)
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try:
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while 1:
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print co.tran(f),
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except EarlyExit:
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pass
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print
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printinorder([1,2,3]) # 1 2 3
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printinorder([[[[1,[2]]],3]]) # ditto
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x = [0, 1, [2, [3]], [4,5], [[[6]]] ]
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printinorder(x) # 0 1 2 3 4 5 6
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# fcmp lexicographically compares the fringes of two nested lists
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def fcmp(l1, l2):
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co1 = Coroutine(); f1 = co1.create(fringe, co1, l1)
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co2 = Coroutine(); f2 = co2.create(fringe, co2, l2)
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while 1:
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try:
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v1 = co1.tran(f1)
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except EarlyExit:
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try:
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v2 = co2.tran(f2)
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except EarlyExit:
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return 0
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co2.kill()
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return -1
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try:
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v2 = co2.tran(f2)
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except EarlyExit:
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co1.kill()
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return 1
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if v1 != v2:
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co1.kill(); co2.kill()
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return cmp(v1,v2)
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print fcmp(range(7), x) # 0; fringes are equal
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print fcmp(range(6), x) # -1; 1st list ends early
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print fcmp(x, range(6)) # 1; 2nd list ends early
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print fcmp(range(8), x) # 1; 2nd list ends early
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print fcmp(x, range(8)) # -1; 1st list ends early
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print fcmp([1,[[2],8]],
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[[[1],2],8]) # 0
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print fcmp([1,[[3],8]],
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[[[1],2],8]) # 1
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print fcmp([1,[[2],8]],
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[[[1],2],9]) # -1
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# end of example
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