empty classes as c structs?

[Nick Coghlan]

Steven Bethard wrote:
> Nick Coghlan wrote:
>> I think the idea definitely deserves mention as a possible 
>> implementation strategy in the generic objects PEP, with the data 
>> argument made optional:
> 
> 
> That's basically what the current implementation does (although I use 
> 'update' instead of '=').  The code is complicated because the 
> implementation also takes all the argument types that dicts take.

The main difference I noticed is that by using update, any changes made via the 
attribute view are not reflected in the original dict.

By assigning to __dict__ directly, you can use the attribute view either as it's 
own dictionary (by not supplying one, or supplying a new one), or as a 
convenient way to programmatically modify an existing one. For example, you 
could use it to easily bind globals without needing the 'global' keyword:

Py> class attr_view(object):
...     def __init__(self, data):
...         self.__dict__ = data
...
Py> def f():
...   gbls = attr_view(globals())
...   gbls.x = 5
...
Py> x
Traceback (most recent call last):
   File "<stdin>", line 1, in ?
NameError: name 'x' is not defined
Py> f()
Py> x
5

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at email.com   |   Brisbane, Australia
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