Hi,
I guess my description was a bit rubbish in retrospec, I dont even
think the title of my email made sense....it doesnt to me now:
class Manager(object):
def __init__(self):
pass
def dosomething(self):
return "RESULTS"
class Foo(object):
def __init__(self):
self.a = "NEE"
What I m trying to do is end up with the following syntax:
f = Foo() # instantiates a Foo object
g= Foo.objects.dosomething() # returns "RESULTS"
The best way I ve found of doing this is overriding new
class Foo(object):
def __new__(cls, *args, **kw):
cls.objects = Manager()
----> If I do it like this, I get exactly what I want - especially if
I change the new method in Manager to one supplied by Bruno.
However, I m playing around with SQLAlchemy (which is going to be used
by some of the Managers I create, others will use different things)
which means that overriding new is not allowed, I cant assign a mapper
to Foo.
So I was trying to think of another way of doing cls.objects =
Manager()....and the only solution I could think of was to use a
decorator and try to do it somehow.......
>From Brunos answer I guess a decorator is not a good way of
accomplishing this, so if there anyway of doing this without using a
metaclass......or by using a decorator or not....any help would be
greatly appreciated.
Many Thanks in advance
Nathan
On 17/09/2007, Bruno Desthuilliers
<[EMAIL PROTECTED]> wrote:
> Nathan Harmston a écrit :
> > HI,
> >
> > I m trying to start an api in a similar way to the djangic way of
> > Class.objects.all(). Ie objects is a "Manager" class.
> >
> > So:
> >
> > class Foo(object):
> > def __init__(self):
> > self.test = "NEE"
> >
> > class Manager(object):
> > def __init__(self):
> > pass
> > def all(self):
> > return "COCONUTS"
> >
> > Because of how some of the code is set up I cant use
> > metaclasses........so I try to use a decorator:
> >
> > def addto(instance):
> > def decorator(f):
> > import new
> > f = new.instancemethod(f, instance, instance.__class__)
> > setattr(instance, "objects", f)
> > return f
> > return decorator
> >
> > class Manager(object):
> > @addto(Foo)
> > def __init__(self):
> > .............
> >
> > however this only binds the init method to the Foo.objects, so not
> > what I want.
>
> Indeed.
>
> > If I try using classmethod...then it just says the
> > Foo.objects doesnt exist.
>
> You mean decorating Manager.__init__ with classmethod ???
>
> I may be wrong, but I suspect you don't have a clear idea of what you're
> doing here.
>
> > Does anyone have any ideas how I can accomplish this using decorators?
>
> Yes : don't use a decorator !-)
>
> Instead of asking for how to implement what you think is the solution,
> you might be better explaining the problem you're trying to solve.
>
> > And also preventing more than one Manager instance instantiated at one
> > time.
>
> Q&D:
>
> class Singleton(object):
> def __new__(cls):
> if not hasattr(cls, '_inst'):
> cls._inst = object.__new__(cls)
> return cls._inst
>
>
> Same remark as above...
> --
> http://mail.python.org/mailman/listinfo/python-list
>
--
http://mail.python.org/mailman/listinfo/python-list
