Question

I’m trying to redifine the __getattr__ method, in a function.

I’ve tried this code:

def foo():
    print("foo")

def addMethod(obj, func):
    setattr(obj, func.__name__, types.MethodType(func, obj))

def __getattr__(obj, name):
    print(name)

addMethod(foo, __getattr__)

foo.bar

but I get this error:

Traceback (most recent call last):
  File blah blah, line 14, in <module>
    foo.bar
AttributeError: 'function' object has no attribute 'bar'

I’ve inspected the “foo” function and it really has the method bounded to it, but it seems that if you set it dynamically, __getattr__ won’t get called.
If I do the same thing to a class, if I set the __getattr__ using my “addMethod” function, the instance won’t call the __getattr__ too!, so the problem must be the dynamic call!

BUT if I put the __getattr__ in the definition of the class, it will work, obviously.

The question is, how can I put the __getattr__ to the function to make it work? I can’t put it from the beginning because it’s a function!, I don’t know how to do this

Thanks!

Answer 1

Well, you don’t. If you want attributes, make a class. If you want instances to be callable, define __call__ for it.

class foo:
    def __call__(self):
        print("foo")

    def __getattr__(self, name):
        print(name)

f = foo()
f()   # foo
f.bar # bar