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Date: Tue, 27 Dec 2011 12:31:10 -0800
From: K Richard Pixley <rich@noir.com>
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To: Ian Kelly <ian.g.kelly@gmail.com>
Subject: Re: confused about __new__
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On 12/27/11 10:28 , Ian Kelly wrote:
> On Tue, Dec 27, 2011 at 10:41 AM, K Richard Pixley<rich@noir.com>  wrote:
>> The conceptual leap for me was in recognizing that a class is just an
>> object.  The best way, (imo, so far), to create a singleton in python is to
>> use the class itself as the singleton rather than ever instantiating it.
>>   With a little work, you can even prevent it from ever being instantiated.
> I don't think that's actually possible:
>
> Python 3.2 (r32:88445, Feb 20 2011, 21:29:02) [MSC v.1500 32 bit
> (Intel)] on win32
> Type "help", "copyright", "credits" or "license" for more information.
>>>> class Foo:
> ...     def __new__(cls):
> ...         raise TypeError
> ...     def __init__(self):
> ...         raise TypeError
> ...
>>>> type(object.__new__(Foo))
> <class '__main__.Foo'>

Try:

class Foo(object):
     def __new__(cls):
         return cls

--rich