Que20

// Stack
struct Stack<T> {
    var items = [T]()
    
    mutating func push(item: T) {
        items.append(item)
    }
    
    mutating func pop() -> T {
        return items.removeLast()

Que20

func imageIsDark(image: CGImage) -> Bool {
    let redLum = 0.299
    let greenLum = 0.578
    let blueLum = 0.114
    let maxLum = 150.0
    guard let imageData = image.dataProvider?.data else { return false }
    guard let ptr = CFDataGetBytePtr(imageData) else { return false }
    let length = CFDataGetLength(imageData)
    let threshold = Int(Double(image.width * image.height) * 0.45)
    var darkPixels = 0

Que20

struct A {
    var v: Bool
    var s: String
}

var arr = [A(v: false, s: "asd"), A(v: true, s: "zxc"), A(v: true, s: "sdf")]


arr = arr.sorted(by: { $0.v && !$1.v })
print(arr)

Que20

import Foundation
import UIKit

protocol PagerViewControllerDelegate: class {
    func pagerViewController(controller: PagerViewController,
        didUpdatePageCount count: Int)
    func pagerViewController(controller: PagerViewController,
        didUpdatePageIndex index: Int)
}

Que20

enum BinaryTree<Element> {
    case leaf
    indirect case node(Element, l: BinaryTree<Element>, r: BinaryTree<Element>)
}

extension BinaryTree {
    init(_ value: Element) {
        self = .node(value, l: .leaf, r: .leaf)
    }
}

Que20

struct T {
	let s: String
	let v: Int
}

let a = [T(s: "abc", v: 0), T(s: "abc", v: 1), T(s: "def", v: 0)]

let b = Array(a.reduce([Int: [T]]()) { (d, a) -> [Int: [T]] in
	var d = d
	let t = a.v

Que20

func input(_ block: (UInt8) -> (Bool)) {
    func initStruct<S>() -> S {
        let struct_pointer = UnsafeMutablePointer<S>.allocate(capacity: 1)
        let struct_memory = struct_pointer.pointee
        struct_pointer.deallocate()
        return struct_memory
    }

    func enableRawMode(fileHandle: FileHandle) -> termios {
        var raw: termios = initStruct()

Que20

// A simple network stack I use for my command line tools written in Swift.
// The dataTask here work only for GET operations.

protocol Operation {
    associatedtype T: Codable
  
    enum HTTPMethod {
        case GET
        case POST
        case PUT

Que20

SwiftUI Navigation Wrapper

Context

I find navigation quite difficult to use in my applied Architecture for SwiftUI project. I made this simpler way to trigger navigation events such as push views and present modals.

Solution

The basic solution I ended up using is this wrapper around NavigationStack. I uses a state variable enum representing the pending navigation operation where it's value changes will trigger the requested operation.

Usage

struct ContentView: View {
    var body: some View {
        NavigationWrapper { navigation in