Swift Objects

By Flavio Copes

In Swift everything is an object that can receive messages. Learn how values get methods and properties, and meet the class, struct, and enum object types.

This tutorial belongs to the Swift series

In Swift, everything is an object. Even the 8 value we assigned to the age variable is an object.

In some languages, objects are a special type. But in Swift, everything is an object and this leads to one particular feature: every value can receive messages.

Each type can have multiple functions associated to it, which we call methods.

For example, talking about the 8 number value, we can call its isMultiple method, to check if the number is a multiple of another number:

A String value has another set of methods.

A type also has instance variables. For example the String type has the instance variable count, which gives you the number of characters in a string:

Swift has 3 different object types, which we’ll see more in details later on: classes, structs and enums.

Those are very different, but they have one thing in common: to object type, we can add methods, and to any value, of any object type, we can send messages.

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