aainaj

struct Device {
    static let IS_IPAD             = UIDevice.current.userInterfaceIdiom == .pad
    static let IS_IPHONE           = UIDevice.current.userInterfaceIdiom == .phone
    static let IS_RETINA           = UIScreen.main.scale >= 2.0
    
    static let SCREEN_WIDTH        = Int(UIScreen.main.bounds.size.width)
    static let SCREEN_HEIGHT       = Int(UIScreen.main.bounds.size.height)
    static let SCREEN_MAX_LENGTH   = Int( max(SCREEN_WIDTH, SCREEN_HEIGHT) )
    static let SCREEN_MIN_LENGTH   = Int( min(SCREEN_WIDTH, SCREEN_HEIGHT) )
    

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class ViewController: UIViewController {

    let wrapperView = UIView()
    let cyanView = UIView()

    override func viewDidLoad() {
        view.backgroundColor = .yellow
        view.addSubview(wrapperView)
        wrapperView.addSubview(cyanView)

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    override var additionalSafeAreaInsets: UIEdgeInsets {
        set {
            super.additionalSafeAreaInsets = UIEdgeInsetsMake(10.0, 50.0, 10.0, 50.0)
        }

        get {
            return UIEdgeInsetsMake(10.0, 50.0, 10.0, 50.0)
        }
    }

aainaj

import UIKit

class ViewController: UIViewController {

    let wrapperView = UIView()
    let cyanView = UIView()

    override func viewDidLoad() {
        view.backgroundColor = .green
        view.addSubview(wrapperView)

aainaj

#!/bin/bash

ITERATION=1
EXTENSION="mp4"
FILENAME="$HOME/Desktop/Simulator Recording.$EXTENSION"

while [ -e "$FILENAME" ]
do
    ITERATION=$((ITERATION+1))
    FILENAME="$HOME/Desktop/Simulator Recording $ITERATION.$EXTENSION"

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    let observable = Observable.from([1, 2, 3]).share()
        let disposeBag = DisposeBag()

        observable.subscribe(onNext: { element in
            print("⛴ \(element)")
        }).addDisposableTo(disposeBag)

        observable.subscribe(onNext: { element in
            print("✈️ \(element)")
            }).addDisposableTo(disposeBag)

aainaj

import Foundation

class ProductFactory {
    var items = 8
}

struct Product {
    let identifier: Int
    let name: String
    let inStock: Bool

aainaj

import Foundation

struct Product {
    let identifier: Int
    let name: String
    var description: String?
  
  init(identifier: Int, name: String) {
    self.identifier = identifier
    self.name = name

aainaj

import Foundation

class ProductFactory: NSObject, NSCopying {
    var items = 8

    func copy(with zone: NSZone? = nil) -> Any {
        let factory = ProductFactory()
        factory.items = items
        return factory
    }

aainaj

Why stack grows down

Any running process has several memory regions: code, read-only data, read-write data, et cetera. Some regions, such as code and read-only data, are static and do not change over time. Other regions are dynamic: they can expand and shrink. Usually there are two such regions: dynamic read-write data region, called heap, and a region called stack. Heap holds dynamic memory allocations, and stack is mostly used for keeping function frames.

Both stack and heap can grow. An OS doesn't know in advance whether stack or heap will be used predominantly. Therefore, an OS must layout these two memory regions in a way to guarantee maximum space for both. And here is the solution:

1. Layout static memory regions at the edges of process's virtual memory
2. Put heap and stack on edges too, and let them grow towards each other: one grows up, one grows down