Chapter 1, The Declarative Programming Style, covers the main idea of declarative style of abstracting away repeating algorithmic patterns and control flows so that, with one statement, it is possible to describe what otherwise would have been 10 lines of imperative code. Functional languages usually have an elaborate infrastructure to make such an approach especially relevant and usable. One good way to feel this difference is to have a look at the difference in programming with Java and Scala collections—the former employs the imperative style and latter the functional style.
Chapter 2, Functions and Lambdas, will start with the concept familiar to an OOP programmer—a method. We will then explore some more advanced, ...
