Re: Python constructors have particular semantics, and ‘Foo.init’ doesn't qualify

Thu Dec 15 13:05:31 EST 2016

On 12/14/2016 11:14 PM, Thomas 'PointedEars' Lahn wrote:
> According to <https://docs.python.org/3/tutorial/classes.html#method-objects>, “Foo.__init__” is _not_ an instance method. Were it an instance
> method, the following would not happen:

This link points to subsection 9.3.4. Method Objects
> | >>> class Foo:
> | ... def __init__ (self):
> | ... pass
> | ...
> | >>> Foo.__init__.__self__
> | Traceback (most recent call last):
> | File "<stdin>", line 1, in <module>
> | AttributeError: 'function' object has no attribute '__self__'

You have misread the docs. Foo.__init__ is the function. 
Foo().__init__ is a method object with the attribute __self__. You 
omitted the ()s.
 >>> class C:
	def __init__(self): pass
	
 >>> ci = C().__init__
 >>> ci.__self__
<__main__.C object at 0x000001E38A750E80>
> Because “Instance method objects have attributes, too: m.__self__ is the
> instance object with the method m() […]”.

This line is from section 9.7. Odds and Ends. In this quote, 'm' is a 
method object, the result of 'instance.method, not a function. In 
Python 2, 'm' would have been called a 'bound method', as opposed to an 
unbound method. Since the latter were eliminated in 3.x, the adjective 
is no longer needed.
-- 
Terry Jan Reedy

Re: Python constructors have particular semantics, and ‘Foo.__init__’ doesn't qualify

Re: Python constructors have particular semantics, and ‘Foo.init’ doesn't qualify