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

[Steven D'Aprano]

On Mon, 15 Apr 2013 21:56:12 -0700, rusi wrote:

> On Apr 16, 7:32 am, Steven D'Aprano <steve
> +comp.lang.pyt... at pearwood.info> wrote:
>>
>> If I had a say in this, I would vote for the first case, with the
>> possible exception of documented singleton types like NoneType and
>> bool.
> 
> How is bool a singleton type?


A doubleton, then.


The point being, GvR declared that bool should guarantee the invariant 
that True and False are the only instances of bool, and if you can 
subclass it, either that invariant is violated, or you can't instantiate 
the subclass.



-- 
Steven