Hi, @Jonathan: thanks! I'll have a look at your links.
So there are actually two issues if I understand correctly: * help() ignoring the property getter when invoked on an instance * built-in class function ignoring the property getter (some_func.__doc__ set to a property returns the property instead of invoking the getter)
Is the second issue also problematic or the built-ins are meant to ignore properties and there should be no fix? I think I'm misunderstanding something here.
Le dim. 7 oct. 2018 à 17:37, Jonathan Fine email@example.com a écrit :
I just couldn't figure out how to make the __doc__ attribute of a
function a getter. Is this a bug or am I making a mistake? If it's my mistake, is there any other way how to dynamically __doc__ a function or am I forced to set __doc__ of a function at the decoration time?
Thank you for your clear examples. I'm not sure, but I may have found the problem.
As I recall, setting obj.attr to a property won't work. Instead, you have to set type(obj).attr to the property. And now you come up against a problem. You can't set __doc__ on the type 'function', nor can you subclass the type 'function'.
def fn(): pass type(fn)
'function(code, globals[, name[, argdefs[, closure]]]) [snip]'
type(fn).__doc__ = None
TypeError: can't set attributes of built-in/extension type 'function'
class FN(type(fn)): pass
TypeError: type 'function' is not an acceptable base type
As I (more vaguely) recall, something was done recently to add a get attribute property that works directly on objects, rather than on instances of a class. But I've not been able to find it. Perhaps I misunderstood PEP 562.
Some perhaps relevant URLs: https://www.python.org/dev/peps/pep-0224/ Attribute Docstrings https://www.python.org/dev/peps/pep-0549/ Instance Descriptors https://www.python.org/dev/peps/pep-0562/ Module __getattr__ and __dir__ https://stackoverflow.com/questions/2447353/getattr-on-a-module