Swift features

When Apple first introduced Swift, it said that Swift is Objective-C without the C. This really only tells us half of the story. Objective-C is a superset of C and provides object-oriented capabilities and a dynamic runtime to the C language. This meant that with Objective-C, Apple needed to maintain compatibility with C, which limited the enhancements it could make to the Objective-C language. As an example, Apple could not change how the switch statement functioned and has still maintained compatibility with the C language.

Since Swift does not need to maintain the same C compatibility as Objective-C, Apple was free to add any feature/enhancement to the language. This allowed Apple to include the best features from many of today's most popular and modern languages, such as Objective-C, Python, Java, Ruby, C#, and Haskell.

The following table shows a list of some of the most exciting enhancements that Swift offers compared to the Objective-C language:

Swift feature	Description
Type inference	Swift can automatically deduce the type of a variable or constant, based on the initial value.
Generics	Generics allow us to write code once to perform identical tasks for different types of objects.
Collection mutability	Swift does not have separate objects for mutable or non-mutable containers. Instead, you define mutability by defining the container as a constant or variable.
Closure syntax	Closures are self-contained blocks of functionality that can be passed around and used in our code.
Optionals	Optionals define a variable that might not have a value.
switch statement	The switch statement has been drastically improved. This is one of my favorite improvements.
Tuples	Functions can have multiple return types by using tuples.
Operator overloading	Classes can provide their own implementations of existing operators.
Enumerations with associated values	In Swift, we can do a lot more than just define a group of related values with enumerations.
Protocols and protocol- oriented design	Apple introduced the protocol-oriented programming paradigm with Swift version 2. This is a new way of not only writing applications but also changing how we think about programming. This is discussed in Chapter 10, Protocol-Oriented Design.

Table 1.1: Swift features

Before we begin our journey into the wonderful world of Swift development, let's take a detour and visit a place that I have loved ever since I was a kid: the playground.