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
-Dan
Steven Bethard wrote:
I tried to Google for past discussion on this topic, but without much
luck. If this has been discussed before, I'd be grateful for a pointer.
Does anyone know why you can't assign a custom mapping type to an
object's __dict__?
py> class M(object):
... def __getitem__(self, key):
... return 42
... def __setitem__(self, key, value):
... pass
...
py> class C(object):
... pass
...
py> c = C()
py> c.__dict__ = M()
Traceback (most recent call last):
File "<interactive input>", line 1, in ?
TypeError: __dict__ must be set to a dictionary
I looked at the source in typeobject.c (where this error originates),
but I'm not fluent enough in CPython yet to be able to tell why a true
dict type is preferred here over just a mapping type...
STeVe
--
http://mail.python.org/mailman/listinfo/python-list