An object is an instance (or not)?

Ned Batchelder ned at nedbatchelder.com
Wed Jan 28 03:21:15 CET 2015


On 1/27/15 7:17 PM, Mario Figueiredo wrote:
> In article <mailman.18191.1422400930.18130.python-list at python.org>,
> ned at nedbatchelder.com says...
>>
>> A common mistake is to believe that "OOP" is a well-defined term.  It's
>> not it's a collection of ideas that are expressed slightly differently
>> in each language.
>
> A common mistake is thinking just because OOP has different
> implementations, it doesn't have a cohesive set of well described rules
> and its own well defined terminology.

I know you think that it has well described rules and terminology.  But 
take a look at this discussion, and maybe realize that the terms are not 
as well-defined, or certainly not as widely accepted as you think.

Do you have a reference that defines these terms?

>
>> I don't know what a "not fully realized object" is.
>
> A fully realized object, in an object oriented paradigm, is an object
> containing or pointing to data and the methods to act on that data. It's
> an instance of a class.
>
> A *not* fully realized object is possible in Python, since Classes are
> first-class objects, despite not being able to participate in OOP.
>>
>> What does "participate in OOP" mean?
>
> Means the object is capable of participating in inheritance and/or
> polymorphism. An instance of an object is capable of doing so, per its
> class definitions. Whereas a Python class object is not.
>
>      >>> class Master:
>              def func(self):
>                  pass
>
>      >>> class Sub(Master):
>              pass
>
>      >>> Sub.func()
>      TypeError: func() missing 1 required positional argument: 'self'


> But somehow I think you knew the answer to all these questions and were
> instead being snarky.

I am not being snarky, I'm trying to understand where our mutual 
incomprehension lies.


-- 
Ned Batchelder, http://nedbatchelder.com




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