On Wednesday 03 June 2015 05:31, Jon Ribbens wrote:
> On 2015-06-02, Dr. Bigcock <dreamingforw...@gmail.com> wrote:
>> On Tuesday, June 2, 2015 at 1:49:03 PM UTC-5, Jon Ribbens wrote:
>>> On 2015-06-02, Dr. Bigcock <dreamingforw...@gmail.com> wrote:
>>> > It doesn't really do anything. No one uses integers as objects.
>>> > (Any dissenters?)
>>>
>>> Yes. *Everyone* uses integers as objects. Containers such as
>>> lists and dictionaries and tuples etc contain objects. If
>>> integers weren't objects then you wouldn't be able to put them
>>> in containers (and you'd end up with Java).
>>
>> Sorry. I meant "object" in the sense of OOP: something you might
>> extend or make a derived class with.
>
> I'm not sure you get to define which properties of objects you want
> not to count.
>
>> Your last claim, must not be true because integers were able to be
>> placed in objects before the type/class unification with v2.6, I
>> believe.
>
> Unless I'm misremembering, before that they were still objects,
> just not quite the same kind of objects as pure-Python ones.
Correct. It was version 2.2, not 2.6, that unified built-in types with
classes. Prior to that, Python had two distinct kinds of object, with
separate hierarchies:
Types (builtins, defined in C)
+-- int
+-- dict
+-- str
+-- list
Classes (custom-made in Python using the class keyword)
+-- Foo
+-- Bar
+-- FooBar
+- FooBarBaz
You could only subclass classes, not types. But *both* were kinds of
objects. They were just separate, with slightly different characteristics.
Starting with 2.2, the old-style classic classes still existed, for
backwards compatibility, but Python introduced a single base-class for the
built-in types, called it "object", and enabled subclassing from pure-Python
code:
Unified types/classes ("new-style classes")
+-- object
+-- int
+-- MyInteger
+-- dict
+-- str
+-- list
+-- MyList
+-- Spam
Classic Classes ("old-style classes")
[unchanged from above]
Finally, in Python 3, the classic classes were removed, and Python now has a
single unified type/class hierarchy, with "object" at the root.
But regardless of whether Python had a single type hierarchy or two separate
hierarchies, all values in Python were still implemented as objects.
--
Steve
--
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