On 25 July 2011 21:47, Robert Kern
<robert.kern@gmail.com> wrote:
On 7/25/11 1:43 PM, Michael Foord wrote:
Some apis (for example those exported directly from C) can't work with something
that isn't a real int.
[~]
|1> import os
[~]
|2> class A(object):
..> def __init__(self,x):
..> self.x = x
..> def __int__(self):
..> return self.x
..> def __index__(self):
..> return self.x
..>
[~]
|10> os.open('foo', A(os.O_RDWR))
21
os.open() just uses PyArg_ParseTuple(), like most extension functions. I'm sure you could write an extension function that would reject A() instances, but it's more work, so most people don't.
Providing __index__ may indeed be enough.
Michael
--
Robert Kern
"I have come to believe that the whole world is an enigma, a harmless enigma
that is made terrible by our own mad attempt to interpret it as though it had
an underlying truth."
-- Umberto Eco
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