Swift tutorial: What are protocols in swift
A protocol defines a blueprint of methods, properties, and other requirements that suit a particular task or piece of functionality. The protocol can then be adopted by a class, structure, or enumeration to provide an actual implementation of those requirements. Any type that satisfies the requirements of a protocol is said to conform to that protocol.
In addition to specifying requirements that conforming types must implement, you can extend a protocol to implement some of these requirements or to implement additional functionality that conforming types can take advantage of.
Protocol Syntax
You define protocols in a very similar way to classes, structures, and enumerations:
protocol SomeProtocol {
// protocol definition goes here
}
Custom types state that they adopt a particular protocol by placing the protocol’s name after the type’s name, separated by a colon, as part of their definition. Multiple protocols can be listed, and are separated by commas:
struct SomeStructure: FirstProtocol, AnotherProtocol {
// structure definition goes here
}
If a class has a superclass, list the superclass name before any protocols it adopts, followed by a comma:
class SomeClass: SomeSuperclass, FirstProtocol, AnotherProtocol {
// class definition goes here
}