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The type.__call__() method manages the calls to __new__ and __init__?

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  The type.__call__() method manages the calls to __new__ and __init__? Marco <name.surname@gmail.com> - 2012-11-20 18:29 +0100
    Re: The type.__call__() method manages the calls to __new__ and __init__? Ian Kelly <ian.g.kelly@gmail.com> - 2012-11-20 12:25 -0700

#33638 — The type.__call__() method manages the calls to __new__ and __init__?

Looking at the documentation of Py3.3:

http://docs.python.org/3.3/reference/datamodel.html#object.__new__

I saw the method `__new__()` is called automatically when I create an 
istance. After the call to __new__(), if it returns an instance `self` 
then `self.__init__()` is called.

Because when I call an instance the __call__ method is called, and 
because the classes are instances of type, I thought when I call a Foo 
class this imply the call type.__call__(Foo), and so this one manages 
the Foo.__new__ and Foo.__init__ calls:

 >>> class Foo:
...     def __new__(cls):
...         print('Foo.__new__()')
...         return super().__new__(cls)
...     def __init__(self):
...         print('Foo.__init__(self)')
...
 >>> f = type.__call__(Foo)
Foo.__new__()
Foo.__init__(self)

Is that right? Thanks in advance


-- 
Marco

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#33647

On Tue, Nov 20, 2012 at 10:29 AM, Marco <name.surname@gmail.com> wrote:
> Because when I call an instance the __call__ method is called, and because
> the classes are instances of type, I thought when I call a Foo class this
> imply the call type.__call__(Foo), and so this one manages the Foo.__new__
> and Foo.__init__ calls:

Yes, that's right.  Observe:

>>> class MetaFoo(type):
...     def __call__(cls):
...         print("before")
...         self = super().__call__()
...         print("after", self)
...         return self
...
>>> class Foo(metaclass=MetaFoo):
...     def __new__(cls):
...         print("__new__")
...         return super().__new__(cls)
...     def __init__(self):
...         print("__init__")
...
>>> f = Foo()
before
__new__
__init__
after <__main__.Foo object at 0x00C55410>

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