Imperative vs. Declarative Swift Programming

Let the worlds collide!

Photo by Joshua Rawson-Harris on Unsplash

Difficulty: Beginner | Easy | Normal | Challenging

This article has been developed using Xcode 11.4.1, and Swift 5.2.2

Prerequisites:

• Coding in Swift Playgrounds (guide HERE)
• Using SwiftUI in Playgrounds (guide HERE)
• Map is used, as are Arrays and for loops

Terminology

Declarative programming: a programming paradigm that uses statements that change a program’s state

Imperative programming: a programming paradigm that expresses the logic of a computation without describing the program flow

The Swift example

In Swift you can generalize (American spelling, sorry mum) that you can code either in an Imperative or a Declarative style.

Let us see a rather simplistic example, in the abstract then using a concrete example, and then in rather more concrete code.

So Imperative can be thought of as telling the machine how to do something step-by-step, and revealing the result. In contrast, a Declarative style opens the door to using a declarative abstraction to produce a result.