48 lines
1.0 KiB
Python
48 lines
1.0 KiB
Python
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# from http://mail.python.org/pipermail/python-dev/2001-June/015239.html
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# if you keep changing a dictionary while looking up a key, you can
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# provoke an infinite recursion in C
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# At the time neither Tim nor Michael could be bothered to think of a
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# way to fix it.
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class Yuck:
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def __init__(self):
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self.i = 0
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def make_dangerous(self):
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self.i = 1
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def __hash__(self):
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# direct to slot 4 in table of size 8; slot 12 when size 16
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return 4 + 8
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def __eq__(self, other):
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if self.i == 0:
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# leave dict alone
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pass
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elif self.i == 1:
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# fiddle to 16 slots
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self.__fill_dict(6)
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self.i = 2
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else:
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# fiddle to 8 slots
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self.__fill_dict(4)
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self.i = 1
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return 1
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def __fill_dict(self, n):
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self.i = 0
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dict.clear()
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for i in range(n):
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dict[i] = i
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dict[self] = "OK!"
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y = Yuck()
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dict = {y: "OK!"}
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z = Yuck()
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y.make_dangerous()
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print dict[z]
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