Literals and Type Inference in Swift

Literally a great type

A literal allows us to represent values in source code, and the compiler supplies us with a range of types to help us out. Furthermore, Swift helps us by inferring types for us.

This all sounds great, so join me for this deep submerge into the topic.

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Difficulty: Beginner | Easy | Normal | Challenging

Terminology

Literal: A representation of a value in source code. An example is the type String in Swift

Type Inference: The automatic detection of data types

Literals

Literals in Swift specify a value rather than a concrete type.

For example, "Hello,World" is a String literal type as Swift initializes the default type for that kind of literal.

This can be revealed with the following:

let str = "Hello, World"
type(of: str) // String.Type

however creating a nil literal will mean that the Swift compiler is unable to infer the type.

type(of: nil) // Creates an error