On Fri, 2007-09-07 at 15:54 +0000, André wrote:
> Unfortunately, it fails. Here's what I tried, followed by the
> traceback
> class SplinterBorg(object):
> _shared_states = {}
> def __new__(cls, *a, **k):
> group = k.pop("group","BORG")
> obj = object.__new__(cls, *a, **k)
> obj.__dict__ = cls._shared_states.setdefault(group,{})
> return obj
>
> class MyClass(SplinterBorg):
> def __init__(self, name):
> self.name = name
>[...]
> Traceback (most recent call last):
> File "test.py", line 15, in <module>
> b1 = MyClass('b', group="B")
> TypeError: __init__() got an unexpected keyword argument 'group'
Indeed, if you have an __init__ method that shouldn't see the "group"
argument, you need a metaclass after all so you can yank the "group"
argument between __new__ and __init__. The following code seems to work,
but it's making my brain hurt:
class SplinterBorgMeta(type):
def __call__(cls, *args, **kwargs):
inst = cls.__new__(cls, *args, **kwargs)
kwargs.pop("group",None)
inst.__init__(*args,**kwargs)
return inst
class SplinterBorg(object):
__metaclass__ = SplinterBorgMeta
_shared_states = {}
def __new__(cls, *a, **k):
group = k.pop("group","BORG")
obj = object.__new__(cls, *a, **k)
obj.__dict__ = cls._shared_states.setdefault(group,{})
return obj
class MyClass(SplinterBorg):
def __init__(self, name):
self.name = name
The alternatives, as Steve just pointed out, would be not to subclass
SplinterBorg or to provide an __init__ method that expects a "group"
argument.
HTH,
--
Carsten Haese
http://informixdb.sourceforge.net
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