Ron Garret schrieb: > One of the things I find annoying about Python is that when you make a > change to a method definition that change is not reflected in existing > instances of a class (because you're really defining a new class when > you reload a class definition, not actually redefining it). So I came > up with this programming style: > > def defmethod(cls): > return lambda (func): type.__setattr__(cls, func.func_name, func) > > class c1(object): pass > > @defmethod(c1) > def m1(self, x): ... > > > Now if you redefine m1, existing instances of c1 will see the change. > > My question is: is there a reason not to do this? Does it screw > something up behind the scenes? Is it unpythonic? Why isn't this > standard operating procedure?
What are you doing that needs this permanent redefinition? I like the repl, yet usually - especially when dealing with classes - I write a text file containing code. So, i just run that on a command line again, if I made some changes, recreating whatever objects I want again. Even if I'd not do that, but used a long-running interpreter inside an IDE (which is what I presume you are doing) - why do you _care_ about the old objects the first place? I mean, you obviously changed the classes for a reason. So, you are not being productive here, but still programming. Which means that you don't _have_ to care about old, unchanged objects too much. But in the end - it's your code. It will run slower, it looks kinda weird as someone who's reading it has to know what it is for, but if it suits your needs - do it. Diez -- http://mail.python.org/mailman/listinfo/python-list
