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author | Raymond Hettinger <python@rcn.com> | 2011-06-25 14:28:07 (GMT) |
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committer | Raymond Hettinger <python@rcn.com> | 2011-06-25 14:28:07 (GMT) |
commit | fd1cb59618b6093d88a6c2f1ffea1656e87dfce3 (patch) | |
tree | c37a8493e435a7bf03e0a65fc2acbfbe233d6429 /Doc | |
parent | 320b91495ad758578cbfc5124ec9e07978eebc19 (diff) | |
download | cpython-fd1cb59618b6093d88a6c2f1ffea1656e87dfce3.zip cpython-fd1cb59618b6093d88a6c2f1ffea1656e87dfce3.tar.gz cpython-fd1cb59618b6093d88a6c2f1ffea1656e87dfce3.tar.bz2 |
Issue 12086: add example showing how to use name mangling.
Diffstat (limited to 'Doc')
-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 5ee9067..f9a2d11 100644 --- a/Doc/tutorial/classes.rst +++ b/Doc/tutorial/classes.rst @@ -553,6 +553,28 @@ 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. |