PavelGnatyuk

extension String: Monoid {
    static var neutral: String = ""
    func operation(_ other: String) -> String {
        self + other
    }
}

PavelGnatyuk

protocol Monoid {
    static var neutral: Self { get }
    func operation(_ other: Self) -> Self
}

PavelGnatyuk

import UIKit

class ViewController: UIViewController {

    private lazy var textFieldName: UITextField = {
        let textField = UITextField()
        textField.translatesAutoresizingMaskIntoConstraints = false
        textField.font = UIFont.preferredFont(forTextStyle: .body)
        textField.borderStyle = .roundedRect
        textField.delegate = self

PavelGnatyuk

var isDebug = true
func assert(_ condition: @autoclosure () -> Bool, _ message: @autoclosure () -> String) {
    guard isDebug else { return }
    if condition() {
        print(message())
    }
}

PavelGnatyuk

func assert(_ condition: @autoclosure () -> Bool, _ message: @autoclosure () -> String) {
    if condition() {
        print(message())
    }
}

func conditionOne() -> Bool {
    return true
}

PavelGnatyuk

func goodMorning(morning: Bool, whom: @autoclosure () -> String) {
    if morning {
        print("Good morning, \(whom())")
    }
}

func giveAname() -> String {
    print("giveAname() is called")
    return "Robert"
}

PavelGnatyuk

func goodMorning(morning: Bool, whom: () -> String) {
    if morning {
        print("Good morning, \(whom())")
    }
}

func giveAname() -> String {
    print("giveAname() is called")
    return "Robert"
}

PavelGnatyuk

func goodMorning(morning: Bool, whom: String) {
    if morning {
        print("Good morning, \(whom)")
    }
}

func giveAname() -> String {
    print("giveAname() is called")
    return "Robert"
}

PavelGnatyuk

func goodMorning(morning: Bool, whom: String) {
    if morning {
        print("Good morning, \(whom)")
    }
}

goodMorning(morning: true, whom: "Pavel")
goodMorning(morning: false, whom: "John")

PavelGnatyuk

// In the second view-controller
let downloader = ImageDownloader()

func downloadImages() {
    let image = self.downloader.download(image: "avatar")
    self.imageView.image = image
        
    //Other code updating all images in the view-controller
}