Hi, I've been looking into ways of creating singleton objects. With Python2.3 I usually used a module-level variable and a factory function to implement singleton objects.
With Python2.4 I was looking into decorators. The examples from PEP 318 http://www.python.org/peps/pep-0318.html#examples don't work - AFAIK because: - you cannot decorate class definitions (why was it left out?) - __init__ must return None However, you can use the decorator: def singleton(f): instances = {} def new_f(*args, **kwargs): if (f not in instances): instances[f] = f(*args, **kwargs) return instances[f] new_f.func_name = f.func_name new_f.func_doc = f.func_doc return new_f with a class that overwrites the __new__ methof of new-style classes: class Foobar(object): def __init__(self): print self @singleton def __new__(self): return object.__new__(Foobar) Is this particularly ugly or bad? Thanks for comments, Ciao Uwe -- http://mail.python.org/mailman/listinfo/python-list
