Basic usage
Input
f = make_factory(5); adder = f.create(3); adder(10)
Output
18
adder(10) computes 10 + 3 + base(5) = 18.
Full lesson preview
Build Nested Function Factories with Shared State
Create a factory that produces configurable inner functions which share and can update a common enclosed state.
Python practice25 minClosures & Function FactoriesAdvancedLast updated April 13, 2026
Problem statement
You will build a nested function factory that demonstrates closures and shared mutable state in Python. Implement a function make_factory(initial_base) that returns an object with three callable attributes:
- create(increment): returns a function adder(x) which computes x + increment + current_base.
- get_base(): returns the current base value.
- set_base(new_base): updates the shared base value for the factory.
Important behavior: adder functions should refer to the shared base dynamically. If set_base changes the base after an adder has been created but before it is called, the adder should use the updated base when called.
Do not use global variables. Use closures/nonlocal to keep the shared state enclosed in the factory.
Task
Implement make_factory(initial_base) that returns an object with create, get_base, and set_base. Inner functions produced by create should use the shared base dynamically.
Examples
Input format
A single expression evaluated against the provided make_factory implementation (e.g., make_factory(5).create(3)(10)).
Output format
Return values of expressions (numbers or other values). Results are compared by their string representation.
Constraints
Do not use global state. The factory must enclose the shared base and allow it to be changed via set_base. adder functions must reflect base changes that occur after creation but before calling.
Samples
Sample 1
Input
make_factory(0).create(2)(4)
Output
6
4 + 2 + base(0) = 6