On Tue, Dec 27, 2011 at 1:31 PM, K Richard Pixley <r...@noir.com> wrote: > On 12/27/11 10:28 , Ian Kelly wrote: >> >> On Tue, Dec 27, 2011 at 10:41 AM, K Richard Pixley<r...@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
Okay: 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): ... return cls ... >>> f1 = object.__new__(Foo) >>> f2 = object.__new__(Foo) >>> type(f1), type(f2) (<class '__main__.Foo'>, <class '__main__.Foo'>) >>> f1 is f2 False -- http://mail.python.org/mailman/listinfo/python-list
