__dict__ attribute for built-in types

[Steven D'Aprano]

On Fri, 28 Oct 2011 01:36:41 +0200, candide wrote:

> Le 28/10/2011 00:57, Hrvoje Niksic a écrit :
> 
>> was used at class definition time to suppress it.  Built-in and
>> extension types can choose whether to implement __dict__.
>>
>>
> Is it possible in the CPython implementation to write something like
> this :
> 
> "foo".bar = 42
> 
> without raising an attribute error ?

No, because built-in strings don't have a __dict__ and so you cannot add 
new attributes that didn't already exist.

But you can subclass str and do whatever you like.

class Str(str):
    pass

Str("foo").bar = 42



-- 
Steven