[Edu-sig] re: Naming in Python

[Rodrigo Dias Arruda Senra]

 [ The Bauman Family <baumanpdx at comcast.net> ]
 -----------------------------------------------
 | Although everybody already knows this, I'm sure, a function actually is 
 | a class, 

 Hi Tim,
 I beg to differ with your statement above. A function is not a class.
 To prove this point follows:

 >>> def m(x): pass
 >>> class M(object): pass
 >>> type(m)
 <type 'function'>
 >>> type(M)
 <type 'type'>
 >>>

 Altough they have similarities. To illustrate the most obvious one:

 >>> callable(m)
 True
 >>> callable(M)
 True

 | so technically it is a function if you have all the things you 
 | get if you dir() a function.

 Perhaps this is a duck typing style of defining what
 an object *is*.  

 But a function is (OO framework sense) definetely an object:

 >>> isinstance(m,object)
 True

 Therefore, a function supports the object protocol:
 
 >>> x = object()
 >>> dir(x)
 ['__class__', '__delattr__', '__doc__', '__getattribute__', '__hash__',
 '__init__', '__new__', '__reduce__', '__reduce_ex__', '__repr__',
 '__setattr__', '__str__']
 
 |  >>> afunction.__repr__.__repr__.__repr__.__repr__()
 | '<method-wrapper object at 0x41152c0c>'
 | 
 | I wonder how Python deals with this endless chain of __repr__'s.

 >>> m
 <function m at 0x402c2a04>
 
 This is the function object.

 >>> m.__repr__()
 '<function m at 0x402c2a04>'

 This is the execution of method __repr__() bound to the function object m

 >>> m.__repr__
 <method-wrapper object at 0x402c870c>

 m.__repr__ is an object (a method-wrapper) representing the method called above.

 >>> m.__repr__.__repr__
 <method-wrapper object at 0x402c878c>

 Every object supports __repr__, even method-wrapper objects.
 
 HTH,

 best regards,
 Rod Senra

-- 
   ,_           
   | )          Rodrigo Senra       <rsenra |at| acm.org>                      
   |(______     -----------------------------------------------
 _(    (|__|]   GPr Sistemas http://www.gpr.com.br                              
_ |    (|___|]  IC - Unicamp http://www.ic.unicamp.br/~921234  
___    (|__|]                       
   L___(|_|]    -----------------------------------------------