Question

Which method can be used to eliminate side effects in functional programming?

a. Move all functions with side effects to a separate library, written in a non-functional language/style.
b. Create new first-class objects that capture state changes and that are created and returned as results from functions.
c. Write code with the desired side effects in public methods of domain classes.

Answer 1

Option b, creating new first-class objects that capture state changes, is the method used in functional programming to eliminate side effects, preserving function purity and encapsulating state changes.

Step-by-step explanation:

The method that can be used to eliminate side effects in functional programming is option b: Create new first-class objects that capture state changes and that are created and returned as results from functions. In functional programming, side effects are generally unwanted as they can lead to bugs and make programs harder to understand and predict. Instead of having functions that alter global state or perform input/output operations, functional programmers encapsulate these changes in first-class objects. These objects can then be passed around and transformed without affecting the global state or causing side effects.

Furthermore, this method is in line with the principles of functional programming, which include immutability, pure functions, and the use of higher-order functions. By following this approach, you can ensure that functions remain pure and that state changes are explicit and controlled.

Answer 2

Create new first-class objects that capture state changes and that are created and returned as results from functions. Option B is the answer.

Step-by-step explanation:

In functional programming, the preferred method to handle side effects is to create new first-class objects that capture state changes and return them as results from functions. This approach aligns with the functional programming paradigm, which emphasizes immutability and avoiding direct modification of external states. By encapsulating state changes within objects returned from functions, the functional purity is maintained, and side effects are controlled.

Options a and c go against the principles of functional programming. Moving functions with side effects to a separate library in a non-functional language (option a) reintroduces imperativeness, while writing code with side effects in public methods of domain classes (option c) violates the principles of immutability and functional purity.

Option B is the answer.