Home Android & Kotlin Books Functional Programming in Kotlin by Tutorials

J
Appendix J: Chapter 10 Exercise Solutions Written by Massimo Carli

Heads up... You're reading this book for free, with parts of this chapter shown beyond this point as scrambled text.

You can unlock the rest of this book, and our entire catalogue of books and videos, with a raywenderlich.com Professional subscription.

Exercise 10.1

What’s the cardinality of the following type?

typealias Triplet = Triple<UByte, Boolean, Unit>

Exercise 10.1 solution

As you learned in the chapter, the cardinality of Triplet is the product of the cardinalities of UByte, Boolean and Unit, which are:

UByte * Boolean * Unit = 256 * 2 * 1 = 512

Exercise 10.2

What’s the cardinality of the following type?

typealias Unique = Pair<Unit, Unit>

Exercise 10.2 solution

Of course, the cardinality of Unique is exactly 1 because Unit is the only existing value of type Unit. Because of this, Unique is isomorphic to Unit.

Exercise 10.3

What’s the cardinality of the following type?

typealias MultiEither = Either<UByte, Either<Boolean, Triage>>
typealias MultiEither2 = Either<Either<UByte, Boolean>, Triage>

Exercise 10.3 solution

In the chapter, you learned that Either<A, B> is a way to represent addition. For this reason, you can represent the previous definition like:

UByte + (Boolean + Triage) = 256 + (2 + 3) = 256 + 5 = 261
(UByte + Boolean) + Triage = (256 + 2) + 3 = 256 + 5 = 261

Have a technical question? Want to report a bug? You can ask questions and report bugs to the book authors in our official book forum here.

© 2022 Razeware LLC

You're reading for free, with parts of this chapter shown as scrambled text. Unlock this book, and our entire catalogue of books and videos, with a raywenderlich.com Professional subscription.

Unlock Now

To highlight or take notes, you’ll need to own this book in a subscription or purchased by itself.