> > Even though "tens", "ones" and "number" all appear as attributes, only > "number" has its input validated. Since the class is designed to only > hold numbers 0 - 99, one can 'break' it by setting self.tens=11, for > example. Should tens and ones be made into full-fledged properties > and validated? Should number have no validation? Is it more pythonic > to encapsulate tightly, or rely on "responsible use."
You could make them double-underscored attributes. That creates some name-mangling that prevents accidential access. But as there is no real private concept in python (and java and C++ protection can be easily overcome), it is considered pythonic to rely on responsible use. If a design for abuse-protection is the ultimate goal, the common suggestion is to use IPC mechanisms to prevent in-process sharing of data and code - that's the only real way to go, regardless of the used language. -- Regards, Diez B. Roggisch -- http://mail.python.org/mailman/listinfo/python-list
