Book Image

Learn Scala Programming

By : Slava Schmidt
Book Image

Learn Scala Programming

By: Slava Schmidt

Overview of this book

The second version of Scala has undergone multiple changes to support features and library implementations. Scala 2.13, with its main focus on modularizing the standard library and simplifying collections, brings with it a host of updates. Learn Scala Programming addresses both technical and architectural changes to the redesigned standard library and collections, along with covering in-depth type systems and first-level support for functions. You will discover how to leverage implicits as a primary mechanism for building type classes and look at different ways to test Scala code. You will also learn about abstract building blocks used in functional programming, giving you sufficient understanding to pick and use any existing functional programming library out there. In the concluding chapters, you will explore reactive programming by covering the Akka framework and reactive streams. By the end of this book, you will have built microservices and learned to implement them with the Scala and Lagom framework.
Table of Contents (19 chapters)

Combining monads

In Chapter 6, Exploring Built-In Effects, we talked about standard effects such as Option, Try, Either, and Future. In Chapter 9, Familiarizing Yourself with Basic Monads, we moved on and implemented monads for all of them. In our examples, we demonstrated how Scala provides nice syntax for the code formulated in monadic terms by having for-comprehension, which is a syntactic sugar for the combination of map, flatMap, and possibly filter methods. In all our examples, we used for-comprehension to define a sequence of steps which constitute some process where the result of the previous computation is consumed by the next step.

For an instance, this is the way we defined the process of fishing in terms of Option in Chapter 6, Exploring Built-In Effects:

val buyBait: String => Option[Bait]
val makeBait: String => Option[Bait]
val castLine: Bait => Option[Line...