The type/object distinction and possible synthesis of OOP and imperative programming languages

[Dave Angel]

On 04/15/2013 01:43 PM, Antoon Pardon wrote:
> Op 15-04-13 12:11, Steven D'Aprano schreef:
>
>>
>> Python's data model has always been 100% object oriented. Prior to the
>> "class/type" unification, it simply had *two distinct* implementations of
>> objects: types, which were written in C, and classes, which were written
>> in Python.
>>
>> After unification, the two kinds of object were no longer entirely
>> distinct -- you could then subclass types in Python code, using the same
>> "class" keyword as you would use for a pure-Python class.
>>
>> And starting with Python 3, the last vestiges of the distinction have
>> disappeared. Now, "class" and "type" are mere synonyms. Both built-in
>> types and custom classes use the same mechanism.
>
> I had gotten my hopes up after reading this but then I tried:
>
>
> $ python3
> Python 3.2.3 (default, Feb 20 2013, 17:02:41)
> [GCC 4.7.2] on linux2
> Type "help", "copyright", "credits" or "license" for more information.
>  >>> class vslice (slice):
> ...   pass
> ...
> Traceback (most recent call last):
>    File "<stdin>", line 1, in <module>
> TypeError: type 'slice' is not an acceptable base type
>
>
> It seems types and classes are still not mere synonyms.

No, it seems you're trying to use an internal detail as though it were a 
supported feature.

 From page:
     http://docs.python.org/3.3/reference/datamodel.html#types

"""Internal types
A few types used internally by the interpreter are exposed to the user. 
Their definitions may change with future versions of the interpreter, 
but they are mentioned here for completeness.
"""


-- 
DaveA