Code made in Swift and Tips for episode "Generics in Swift: Protocols with associated types" https://youtu.be/pp4hKZBBci4

GenericsAssociatedTypes.swift

import Foundation

// MARK: - Associated Types
// Placeholder name to a type that is used as part of a protocol.
// The actual type for the associated type isn't specified until the protocol is adopted.
// Use associatedtype keyword

protocol Stack {
    associatedtype Element
    var count: Int { get }
    mutating func push(_ element: Element)
    mutating func pop() -> Element?
}

struct IntStack: Stack {
    private var values: [Int] = []

    var count: Int {
        values.count
    }

    mutating func push(_ element: Int) {
        values.append(element)
    }

    mutating func pop() -> Int? {
        values.popLast()
    }
}

var stack1 = IntStack()
stack1.push(1)
stack1.push(2)
stack1.push(3)




// MARK: - Generic Type using a protocol with associated type


struct MyStack<Item>: Stack {
    private var values: [Item] = []

    var count: Int {
        values.count
    }

    mutating func push(_ element: Item) {
        values.append(element)
    }

    mutating func pop() -> Item? {
        values.popLast()
    }
}

var stack2 = MyStack<Int>()
stack2.push(4)
stack2.push(5)
stack2.push(6)

var stack3 = MyStack<String>()
stack3.push("Hello")
stack3.push("World")
stack3.push("Everybody!")



// MARK: - Extending from a protocol with associated types


extension Array: Stack {
    mutating func push(_ element: Element) {
        self.append(element)
    }

    mutating func pop() -> Element? {
        self.popLast()
    }
}


// MARK: - How to solve "Protocol 'Stack' can only be used as a generic constraint ..."?

func executeOperation<Container: Stack>(container: Container) {

}