[Python-ideas] Properties for classes possible?

[Nathaniel Smith]

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