assigning a custom mapping type to __dict__

[Duncan Booth]

Daniel Cer wrote:

> Why not just inherit from dict? That seems to work.
> 
> >>> class M(dict):
> ...   def __getitem__(self,key):
> ...     return 42
> ...   def __setitem__(self,key,value):
> ...     pass
> ...
> >>> class C(object):
> ...    pass
> ...
> >>> c = C()
> >>> c.__dict__ = M()
> >>> c.__dict__['x']
> 42
> 

Didn't test this very much, did you?

>>> c.x

Traceback (most recent call last):
  File "<pyshell#23>", line 1, in -toplevel-
    c.x
AttributeError: 'C' object has no attribute 'x'

Or even:

>>> c = C()
>>> c.__dict__ = M({'x': 1})
>>> c.x
1
>>> c.__dict__['x']
42
>>>