[Python-ideas] Properties for classes possible?
Nathaniel Smith
njs at pobox.com
Thu Aug 20 09:47:22 CEST 2015
On Thu, Aug 20, 2015 at 12:20 AM, Andrew Barnert via Python-ideas
<python-ideas at python.org> wrote:
> Modules are a more serious problem, because there's no immediate way to specify the type for a module object. You can work around it by, e.g., declaring a module subclass, copying the module's dict to an instance of that subclass, then replacing the entry in sys.modules, but this is more than a little ugly.
>
> There have been proposals to allow modules to specify a type (e.g., something similar to the way __metaclass__ worked in 2.x), and to make it easier to hook the import machinery to create modules of a custom type, and probably other variations on this. You might want to search this list and -dev for previous ideas, to find one you think should be reconsidered.
This is already done :-). Python 3.5 allows a module to contain code like:
class MetaModule(types.ModuleType):
@property
def some_attribute(self):
print("Accessing module.some_attribute")
return 1
sys.modules[__name__].__class__ = MetaModule
See also
https://pypi.python.org/pypi/metamodule
for utility code and a polyfill back to ancient Pythons.
-n
--
Nathaniel J. Smith -- http://vorpus.org
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