On 13Dec2016 12:27, paoli...@gmail.com <paoli...@gmail.com> wrote:
The official Python tutorial at https://docs.python.org/3/tutorial/classes.html#private-variablessays that "name mangling is helpful for letting subclasses override methods without breaking intraclass method calls" and makes an interesting example: class Mapping: def __init__(self, iterable): self.items_list = [] self.__update(iterable) def update(self, iterable): for item in iterable: self.items_list.append(item) __update = update # private copy of original update() method class MappingSubclass(Mapping): def update(self, keys, values): # provides new signature for update() # but does not break __init__() for item in zip(keys, values): self.items_list.append(item) It seems to me that, in this example, one could just have: class Mapping: def __init__(self, iterable): self.items_list = [] Mapping.update(self, iterable) def update(self, iterable): for item in iterable: self.items_list.append(item) and avoid copying 'Mapping.update' into 'Mapping.__update'. More generally, any time one needs to "let subclasses override methods without breaking intraclass method calls" (the goal stated in the tutorial), using qualified access to class attributes/methods should suffice. Am I missing something? Is 'self.__update(iterable)' in 'Mapping.__init__' preferable to 'Mapping.update(self, iterable)'?
IMO, mostly in that "Mapping.update" hardwires the class name, whereas "self.__update" will survive a class rename.
I confess I've never used name mangling in the manner shown in the example. Hoping for more insightful comments... Cheers, Cameron Simpson <c...@zip.com.au> -- https://mail.python.org/mailman/listinfo/python-list
