How do I programmatically set the docstring?
An instancemethod
gets its docstring from its __func__
. Change the docstring of __func__
instead. (The __doc__
attribute of functions are writeable.)
>>> class Foo(object):... def bar(self):... pass...>>> Foo.bar.__func__.__doc__ = "A super docstring">>> help(Foo.bar)Help on method bar in module __main__:bar(self) unbound __main__.Foo method A super docstring>>> foo = Foo()>>> help(foo.bar)Help on method bar in module __main__:bar(self) method of __main__.Foo instance A super docstring
From the 2.7 docs:
User-defined methods
A user-defined method object combines a class, a class instance (or None) and any callableobject (normally a user-defined function).
Special read-only attributes: im_self is the class instance object, im_func is the functionobject; im_class is the class of im_self for bound methods or the class that asked for themethod for unbound methods;
__doc__
is the method’s documentation (same asim_func.__doc__
);__name__
is the method name (same asim_func.__name__
);__module__
is the name of the module the method was defined in, or None if unavailable.Changed in version 2.2: im_self used to refer to the class that defined the method.
Changed in version 2.6: For 3.0 forward-compatibility, im_func is also available as
__func__
, and im_self as__self__
.
I would pass the docstring into the factory function and use type
to manually construct the class.
def make_testcase(filename, myfunc, docstring): def test_something(self): data = loadmat(filename) result = myfunc(data) self.assertTrue(result > 0) clsdict = {'test_something': test_something, '__doc__': docstring} return type('ATest', (unittest.TestCase,), clsdict)MyTest = makeTestCase('some_filename', my_func, 'This is a docstring')
This is an addition to the fact that the __doc__
attribute of classes of type type
cannot be changed. The interesting point is that this is only true as long as the class is created using type. As soon as you use a metaclass you can actually just change __doc__
.
The example uses the abc (AbstractBaseClass) module. It works using a special ABCMeta
metaclass
import abcclass MyNewClass(object): __metaclass__ = abc.ABCMetaMyClass.__doc__ = "Changing the docstring works !"help(MyNewClass)
will result in
"""Help on class MyNewClass in module __main__:class MyNewClass(__builtin__.object) | Changing the docstring works !"""