how to create top-level module function from another function?

Question

Given a module mymodule with an __init__.py file how can I define a functions of mymodule from another function within that file?

__init__.py code outline:

def a():
    THISMODULE.__dict__["b"] = lambda: print("this is not weird")

a()
b() # Expect "this is not weird" output

mymodule comes as a replacement for anothermodule and I want to make the code change as simple as replacing import anothermodule as thething with import mymodule as thething. Since I don't implement all the functions of anothermodule just yet, I would like to send the user a notification about it instead of crashing with "not defined".

Does the name have to be dynamic? If not simply `global b` and `b = lambda...` will work fine. What's the context - what are you trying to achieve here? — jonrsharpe, Aug 18 '20 at 15:05
I don't know the names upfront and have to access them through the `__dict__` — y.selivonchyk, Aug 18 '20 at 15:06
I'd like to mock another module. Mock every function with a swallow-all stabs and a few with something more elaborate. — y.selivonchyk, Aug 18 '20 at 15:08
Please [edit] to elaborate, that seems like a test/architecture smell. — jonrsharpe, Aug 18 '20 at 15:08
In that case why not `from anothermodule import *` until you've overridden everything? Or if that won't work, use a module-level `__getattr__` per e.g. https://stackoverflow.com/q/2447353/3001761. — jonrsharpe, Aug 18 '20 at 15:23
functions of `anothermodule` would not work any longer. __getattr__ is good suggestion. — y.selivonchyk, Aug 18 '20 at 16:42

score 1 · Accepted Answer · answered Aug 18 '20 at 15:03

__name__ is a module attribute set by the import machinery, which evaluates to the name of the current module. Adding this to the top of your file:

import sys

THISMODULE = sys.modules[__name__]

And the rest of what you already have should work correctly.

how to create top-level module function from another function?

1 Answers1