[Python-Dev] Exception for setting attributes of built-in type

[Seo Sanghyeon]

Exception for setting attributes of built-in type differs between
CPython and IronPython. This is not purely theoretical, as
zope.interface tries to set Implements declaration as __implemented__
attribute of built-in type object, and excepts TypeError.

Python 2.6.1
>>> object.flag = True
TypeError: can't set attributes of built-in/extension type 'object'

IronPython 2.6
>>> object.flag = True
AttributeError: 'object' object has no attribute 'flag'

I was surprised that CPython raises TypeError. Library Reference seems
to mention it here:

exception AttributeError
Raised when an attribute reference or assignment fails. (When an
object does not support attribute references or attribute assignments
at all, TypeError is raised.)
http://docs.python.org/library/exceptions.html

What does it mean that "an object does not support attribute
references or attribute assignments at all"?

-- 
Seo Sanghyeon