![]() Wrapped = property(func.fget, func.fset, func.fdel, doc)Ĭlss = filter(lambda c: name in vars(c).keys() and not getattr(c, name)._doc_, cls.mro())įunc = func. # With that approach (using dir(cls) instead of var(cls)) # if cls owns it or search where it's coming from. # We don't want to introduce new properties, therefore check # The work-around below wraps the property into a new property. I also came across a situation where I had to use func._func_ (for "instancemethod"s), but I'm not completely sure why the other solutions didn't encouter that problem. The following adaptation also handles properties and mixin classes. And for another example, the functools.wraps decorator copies metadata from one function to another. For example, the functools.total_ordering class decorator add missing rich comparison methods to classes. This is a Pythonic technique that exactly matches the design of existing tools in the standard library. In newer Python versions, the last part is even more simple and beautiful: Dog(Animal): ![]() If parfunc and getattr(parfunc, '_doc_', None): If isinstance(func, types.FunctionType) and not func._doc_: Here's a first cut at how to do it: import types In later versions, you can apply with the notation. Inheritance allows us to reuse code from a class. For example: a car is a vehicle, or a dog is an animal. Inheritance is usually referred to as an Is-A relationship. In Python2.5, you can apply it directly after the class is created. Inheritance allows us to define a sub or child class which inherits functionality from another class, otherwise known as a base class or a parent class. Write a function in a class-decorator style to do the copying for you. Self.assertEqual(Baz.frobnicate._doc_, 'Frobnicate this gonk.') Self.assertEqual(Bar.frobnicate._doc_, 'Frobnicate this gonk.')Ĭlass Baz(Bar, metaclass=DocStringInheritor): Self.assertEqual(Bar.frobnicate._doc_, None) Self.assertEqual(Bar()._doc_, object._doc_) Self.assertEqual(Bar._doc_, object._doc_) Return type._new_(meta, name, bases, clsdict)Ĭlass Bar(Foo, metaclass=DocStringInheritor): You'll improve your object-oriented programming (OOP) skills by understanding how to use inheritance and composition and how to leverage them in their design. If not('_doc_' in clsdict and clsdict):įor mro_cls in (mro_cls for base in bases for mro_cls in base.mro()):įor mro_cls in (mro_cls for base in bases for mro_cls in base.mro()ĭoc=getattr(getattr(mro_cls,attr),'_doc_')Ĭlsdict = property(attribute.fget, attribute.fset, In this step-by-step tutorial, you'll learn about inheritance and composition in Python. Unlike with a class decorator, the metaclass is inherited, so you only need to set the metaclass once in some top-level base class, and docstring inheritance will occur throughout your OOP hierarchy.It can inherit the docstring from any class inĪny of the base classes's MROs, just like regular attribute inheritance.It inherits a parent class docstring if the child class docstring is. ![]()
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