[Python-checkins] python/dist/src/Lib ftplib.py,1.66,1.67
Guido van Rossum
guido@python.org
Wed, 08 May 2002 12:02:31 -0400
> Is this patch a good idea? Now you can pass all sorts of garbage as
> callback (callback="hello") and it'll be silently ignored. I would think
> something like "if not callback is None:" or so would be better...
I think Martin will change it to that, yes.
> And in general I think it's unwise in Python to have an object that
> tests false (because it's __len__ returns 0, in the case of this bug
> report) but is still expected to do something. "if object:
> do_something_with(object)" is fairly standard Python idiom.
But it's a time bomb waiting to go off! The correct code should read
"if object is not None: do_something_with(object)". There are lots of
objects that (for better or for worse!) define __len__. So beware.
--Guido van Rossum (home page: http://www.python.org/~guido/)