diff options
| -rw-r--r-- | Doc/tutorial/classes.rst | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/Doc/tutorial/classes.rst b/Doc/tutorial/classes.rst index a328ab2..bf1e26e 100644 --- a/Doc/tutorial/classes.rst +++ b/Doc/tutorial/classes.rst @@ -595,6 +595,28 @@ current class name with leading underscore(s) stripped. This mangling is done without regard to the syntactic position of the identifier, as long as it occurs within the definition of a class. +Name mangling is helpful for letting subclasses override methods without +breaking intraclass method calls. For 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) + Note that the mangling rules are designed mostly to avoid accidents; it still is possible to access or modify a variable that is considered private. This can even be useful in special circumstances, such as in the debugger. |