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Diffstat (limited to 'Doc/reference/datamodel.rst')
-rw-r--r-- | Doc/reference/datamodel.rst | 33 |
1 files changed, 33 insertions, 0 deletions
diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst index cd11020..9752494 100644 --- a/Doc/reference/datamodel.rst +++ b/Doc/reference/datamodel.rst @@ -1500,6 +1500,39 @@ access (use of, assignment to, or deletion of ``x.name``) for class instances. returned. :func:`dir` converts the returned sequence to a list and sorts it. +Customizing module attribute access +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +.. index:: + single: __class__ (module attribute) + +For a more fine grained customization of the module behavior (setting +attributes, properties, etc.), one can set the ``__class__`` attribute of +a module object to a subclass of :class:`types.ModuleType`. For example:: + + import sys + from types import ModuleType + + class VerboseModule(ModuleType): + def __repr__(self): + return f'Verbose {self.__name__}' + + def __setattr__(self, attr, value): + print(f'Setting {attr}...') + setattr(self, attr, value) + + sys.modules[__name__].__class__ = VerboseModule + +.. note:: + Setting module ``__class__`` only affects lookups made using the attribute + access syntax -- directly accessing the module globals (whether by code + within the module, or via a reference to the module's globals dictionary) + is unaffected. + +.. versionchanged:: 3.5 + ``__class__`` module attribute is now writable. + + .. _descriptors: Implementing Descriptors |