Re: Creating new types and invoking super
- From: "Guilherme Polo" <ggpolo@xxxxxxxxx>
- Date: Wed, 23 Jan 2008 20:42:02 -0200
2008/1/23, Guilherme Polo <ggpolo@xxxxxxxxx>:
2008/1/23, Arnaud Delobelle <arnodel@xxxxxxxxxxxxxx>:
On Jan 23, 8:55 pm, "Guilherme Polo" <ggp...@xxxxxxxxx> wrote:
Hello,
Hi
[...]
First I tried this:
def init(func):
def _init(inst):
super(inst.__class__, inst).__init__()
func(inst)
return _init
class A(object):
@init
def __init__(self): pass
This kind of approach can't work, you need to call super(A, obj).
super(type(obj), obj) is pointless, it defeats the whole purpose of
the mro!
Yeh, as shown in the next examples in the previous email. Using a
decorator for that doesn't sound useful at all, was just trying
something different ;) I will stick to the no-decorator option.
The only way I can think of would be to create a metaclass, but I
don't think it's worth it. super(A, obj).__init__() isn't that bad!
Metaclass doesn't apply here because metaclass is related to
class-construction. This is related to instance initialization, and
I'm creating the types as the user asks.
Oops, actually it can be done. But I am not going to stick to it, just
did a sample here that "solves" for a not so deep structure:
def init(func):
def _init(cls):
if hasattr(cls, "myclass"):
super(cls.myclass, cls).__init__()
else:
super(cls.__class__, cls).__init__()
func(cls)
return _init
class M(type):
def __new__(cls, classname, bases, classdict):
if not len(classdict):
if 'myclass' in bases[0].__dict__:
classdict['myclass'] = bases[0].__dict__['myclass']
else:
classdict['myclass'] = bases[0]
return type.__new__(cls, classname, bases, classdict)
class Y(object):
__metaclass__ = M
class X(Y):
@init
def __init__(self):
print "X"
X()
y = type("Z", (X, ), {})
w = type("W", (y, ), {})
y()
w()
--
Arnaud
--
http://mail.python.org/mailman/listinfo/python-list
--
-- Guilherme H. Polo Goncalves
--
-- Guilherme H. Polo Goncalves
.
- References:
- Creating new types and invoking super
- From: Guilherme Polo
- Re: Creating new types and invoking super
- From: Arnaud Delobelle
- Creating new types and invoking super
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