I V wrote: > Nicola Musatti wrote: [...] > > Factory functions (or classes) are there to solve this problem and > > still allow a clean separation of concerns. Although instances of Klass > > are created uninitialized, they only live in this state within their > > factory and only reach trhe outside world only when they are in a > > usable state. > > This may be my limited imagination, but I can't think of a situation > when you would prefer something like: > > def factory(info): > k = Klass() > data = get_initial_data(info) > k.set_data(data) > return k > > to: > > def factory(info): > data = get_initial_data(info) > return Klass(data) > > What would be the value of doing the initialization in a separate > method, rather than the constructor?
I didn't express my intent clearly. I agree that in general your second example is to be preferred to the first one. In fact the only reason I could think of using the first scheme is when the second would lead to Klass's __init__ method having a large number of parameters. What is important to me is to keep your get_initial_data() function outside Klass if it's task is non trivial, e.g. it has to interact with the OS or a DB. Cheers, Nicola Musatti -- http://mail.python.org/mailman/listinfo/python-list
