Scala Functional Programming in Scala 3

Question 1

What is a monad in Scala functional programming?

Accepted Answer

A type that supports `flatMap` and `unit` operations following specific laws

Answer

A monad is an abstraction that wraps a value and supports `flatMap` (chain) and `unit` (wrap) while satisfying identity and associativity laws.

Question 2

Which annotation verifies that a recursive Scala function is tail-recursive?

Accepted Answer

@tailrec

Answer

The `@tailrec` annotation from `scala.annotation.tailrec` causes the compiler to verify and optimize tail-recursive functions.

Question 3

What is currying in Scala?

Accepted Answer

Transforming a function taking multiple parameters into a chain of single-parameter functions

Answer

Currying transforms a function `f(a, b)` into `f(a)(b)`, enabling partial application and function composition.

Question 4

What does `zip` do when called on two Scala Lists?

Accepted Answer

Creates tuples pairing elements at corresponding positions

Answer

`zip` pairs elements from two collections by index into tuples, stopping at the shorter collection's length.

Question 5

What is partial function application in Scala?

Accepted Answer

Applying a function to some but not all arguments to create a new function

Answer

Partial application fixes some arguments of a function, returning a new function that takes the remaining arguments.

Scala Practice Test