Re: singleton decorator

[EMAIL PROTECTED] a écrit : > Hallo, > playing with the decorators from PEP 318 I found the elegant singleton > decorator. > > def singleton(cls): > instances = {} > def getinstance(): > if cls not in instances: > instances[cls] = cls() >

singleton decorator

Hallo, playing with the decorators from PEP 318 I found the elegant singleton decorator. def singleton(cls): instances = {} def getinstance(): if cls not in instances: instances[cls] = cls() return instances[cls] return getinstance @singleton class A: pass

Re: singleton decorator

On Tue, 08 Aug 2006 14:50:39 +0200 Wildemar Wildenburger <[EMAIL PROTECTED]> wrote: > Or you could always just use the __new__() method instead of > __init__(), putting all your initialization into the above > except-block. If you replace 'cls._it = ...' with 'self = cls_it = > ...' you'll feel

Re: singleton decorator

Pedro Werneck wrote: class Singleton(object): > ... def __new__(cls, *args, **kwds): > ... try: > ... return cls._it > ... except AttributeError: > ... cls._it = object.__new__(cls, *args, **kwds) > ... ret

Re: singleton decorator

Andre Meyer wrote: > Am I missing something here? What is the preferred pythonic way of > implementing singleton elegantly? > > Thanks for your help > André Hi Andre, You might also google for python borg pattern As a discussion on the 'borg' design pattern might be informative. - Pad. -- ht

Re: singleton decorator

Andre Meyer wrote: > While looking for an elegant implementation of the singleton design > pattern I came across the decorator as described in PEP318 > . > Unfortunately, the following does not work, because decorators only work > on functions or methods

Re: singleton decorator

[EMAIL PROTECTED] wrote: > Andre Meyer: >> What is the preferred pythonic way of implementing singleton elegantly? > > Maybe to just use a module. > > Bye, > bearophile > Here is some sample code for both singleton classes and named classes that I use: > class Singleton(type): > """ >

Re: singleton decorator

On Tue, 8 Aug 2006 01:33:31 +0200 "Andre Meyer" <[EMAIL PROTECTED]> wrote: > > Am I missing something here? What is the preferred pythonic way of > implementing singleton elegantly? I think the most "elegant" is with a metaclass, since I feel like a singleton is not just an ordinary type (and __

Re: singleton decorator

Andre Meyer wrote: > Am I missing something here? What is the preferred pythonic way of > implementing singleton elegantly? Create a class and then derive from it. There are examples on the Cookbook. -- Erik Max Francis && [EMAIL PROTECTED] && http://www.alcyone.com/max/ San Jose, CA, USA &

Re: singleton decorator

Andre Meyer: > What is the preferred pythonic way of implementing singleton elegantly? Maybe to just use a module. Bye, bearophile -- http://mail.python.org/mailman/listinfo/python-list

Re: singleton decorator

Andre Meyer wrote: > Am I missing something here? What is the preferred pythonic way of > implementing singleton elegantly? The "Open Issues" section of that PEP says the following: "It's exceedingly unlikely that class decorators will be in Python 2.4" So it might not be in the current version

singleton decorator

While looking for an elegant implementation of the singleton design pattern I came across the decorator as described in PEP318.Unfortunately, the following does not work, because decorators only work on functions or methods, but not on classes. def singleton(cls):instances = {}def getinstan