George Sakkis a écrit : > On Jul 20, 5:40 am, Bruno Desthuilliers <bruno. > [EMAIL PROTECTED]> wrote: > >>Aahz a écrit : >> >> >>>In article <[EMAIL PROTECTED]>, >>>Bruno Desthuilliers <[EMAIL PROTECTED]> wrote: >>> >>>>To make a long story short: Python 2.2 introduced a new object model >>>>which is more coherent and more powerful than the original one. The old >>>>one was kept so far for compatibility reasons, but there's absolutely no >>>>reason to use it no more since "new-style" classes can do anything >>>>"Classic" classes did and much more. IOW, don't even bother with >>>>old-style classes. >> >>>And I'll make my usual knee-jerk response disagreeing with this. For >>>more info, search groups.google.com. >> >>And you'll still make it harder for newcomers to understand why a lot of >>things don't work correctly with their classes. How helpful... >> >>Aahz, the object model switch happened *years* ago, and it's quite clear >>that old style classes have been kept so far for compatibility reasons >>only. It's obvious that one doesn't gain *anything* - except compat with >>years-old pre-2.2 versions of Python - using old-style classes. So *why* >>on earth are you still *advocating* the use of old style classes ?????? > > > FWIW, I am not advocating old style classes and I rarely (if ever) use > them in new code, but I occasionally miss the following feature, which > by the way disproves the assertion that "new-style classes can do > anything Classic classes did": > > class Classic: pass > class NewStyle(object):pass > > for o in Classic(),NewStyle(): > o.__str__ = lambda: 'Special method overriding works on > instances!' > print '%s object: %s' % (o.__class__.__name__, o) >
Good point. There are effectively a couple of things that did work with the old object model and don't with the new one. OTOH, and while I tend to make heavy use of Python's dynamism and advanced features, I never had the need to dynamically override special methods on a per-instance basis yet. Not to say this is useless, just that it's probably enough of a corner case to justify the design choice (YMMV of course). -- http://mail.python.org/mailman/listinfo/python-list
