On Mon, Dec 6, 2010 at 2:47 PM, Alan Gauld <alan.ga...@btinternet.com> wrote: > Oops, too quick. I neant to add: > > But this line seems to return a value so the return values of this function > seem to be incompatible which is not a good design pattern.
I agree it's not the clearest way to do this, but not because of incompatible return values. Attribute and Method access have the same syntax on objects, and __getattr__ is only called if the attribute isn't found "in the usual places," so it won't hide other methods. In other words: >>> a = Structure() >>> a["spam"] = 5 >>> a.__getstate__() None >>> a.spam 5 Doesn't look that strange to me, interface-wise. Attribute access sometimes returns a function and sometimes not. The comment specifically states it's faking a method, so it's pretty clear. I do have a few other gripes though: * why not just define __getstate__ in the class? why return a new lambda every time when you can just write "def __getstate__(self): return None" and be done with it? This also simplifies getattr. * it's now impossible to have keys that collide with a method name: dict, items, keys, clear, popitem, et cetera. You can set them without error, but when you try to get them you'll get the old method, which might cause hard-to-find bugs * it's not much of an advantage over regular dicts, really. You limit yourself to string keys, you make it very unclear that you're using a dict, it's not as efficient, and really just unpythonic in general. Why do this at all? To make python more Matlab-like? Hugo _______________________________________________ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
