empty classes as c structs?

[Steven Bethard]

Michael Spencer wrote:
> ISTM that 'bunch' or 'namespace' is in effect the complement of vars 
> i.e., while vars(object) => object.__dict__, namespace(somedict) gives 
> an object whose __dict__ is somedict.

Yeah, I kinda liked this application too, and I think the symmetry would 
be nice.

> Looked at this way, namespace (or bunch) is a minimal implementation of 
> an object that implements the hasattr(object,__dict__) protocol.  The 
> effect of the class is to make operations on __dict__ simpler.  
> namespace instances can be compared with any other object that has a 
> __dict__.  This differs from the PEP reference implementation which 
> compares only with other bunch instances.

Yeah, I wanted to support this, but I couldn't decide how to arbitrate 
things in update -- if a dict has a __dict__ attribute, do I update the 
Namespace object with the dict or the __dict__?  That is, what should I 
do in the following case:

py> class xdict(dict):
...     pass
...
py> d = xdict(a=1, b=2)
py> d.x = 1
py> d
{'a': 1, 'b': 2}
py> d.__dict__
{'x': 1}
py> Namespace(d)

The dict d has both the items of a dict and the attributes of a 
__dict__.  Which one gets assigned to the __dict__ of the Namespace?  Do 
I do:

     self.__dict__ = d

or do I do:

     self.__dict__ = d.__dict__

It was because these seem like two separate cases that I wanted two 
different functions for them (__init__ and, say, dictview)...

Steve