format.py

import inspect
from collections import ChainMap


def f(fmt):
    frame = inspect.currentframe()
    try:
        vars = ChainMap(frame.f_back.f_locals, frame.f_back.f_globals)
        # from pprint import pprint
        # pprint(vars)
        return fmt.format(**vars)
    finally:
        del frame


name = "simon"
movie = "groundhog day"
print(f("{name}'s favorite movie is {movie}."))
# Prints: simon's favorite movie is groundhog day.


def outer():
    movie = "american psycho"  # Supports scoping properly.

    def inner():
        nonlocal movie  # Required for f to find the movie variable, globals don't need to be listed here i.e. `name`.
        # Without nonlocal, the global `movie` variable is used. If there were no global named `movie`, it would
        # raise an exception.

        print(f("{name}'s favorite movie is {movie}."))
        # Prints: simon's favorite movie is american psycho.

    inner()


outer()