Functional Programming For Dummies

Chapter 4

Defining the Functional Difference

IN THIS CHAPTER

Examining declarations

Working with functional data

Creating and using functions

As described in Chapter 1 and explored in Chapters 2 and 3, using the functional programming paradigm entails an approach to problems that differs from the paradigms that languages have relied on in the past. For one thing, the functional programming paradigm doesn’t tie you to thinking about a problem as a machine would; instead, you use a mathematical approach that doesn’t really care about how the machine solves the problem. As a result, you focus on the problem description rather than the solution. The difference means that you use declarations —formal or explicit statements describing the problem — instead of procedures — step-by-step problem solutions.

To make the functional paradigm work, the code must manage data differently than when using other paradigms. The fact that functions can occur in any order and at any time (allowing for parallel execution, among other things) means that functional languages can’t allow mutable variables ...