kastiglione

wut() {
  readonly error_code=$1
  local domain
  for domain in posix mach; do
    tput bold; echo $domain; tput sgr0
    launchctl error $domain $error_code
  done

  tput bold; echo security; tput sgr0
  security error $error_code

smileyborg

// UICollectionView Objective-C example

- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
        
    NSIndexPath *selectedIndexPath = [[self.collectionView indexPathsForSelectedItems] firstObject];
    if (selectedIndexPath != nil) {
        id<UIViewControllerTransitionCoordinator> coordinator = self.transitionCoordinator;
        if (coordinator != nil) {
            [coordinator animateAlongsideTransition:^(id<UIViewControllerTransitionCoordinatorContext> context) {

kastiglione

void addMainThreadCheck(Class cls, SEL selector) {
#if DEBUG
    void *symbol = dlsym(RTLD_DEFAULT, "__main_thread_add_check_for_selector");
    if (!symbol) {
        return;
    }
    void (*addCheck)(Class, SEL) = (__typeof__(addCheck))symbol;
    addCheck(cls, selector);
#endif
}

0xced

#import <Foundation/Foundation.h>

static NSString * _Nonnull ActuallyLocalizedStringForStatusCode(NSInteger statusCode)
{
	static NSBundle *cfNetworkBundle;
	static dispatch_once_t once;
	dispatch_once(&once, ^{
		cfNetworkBundle = [NSBundle bundleForClass:NSHTTPURLResponse.class];
	});
	NSString *httpError = [NSHTTPURLResponse localizedStringForStatusCode:statusCode];

Catfish-Man

As of iOS 11/macOS High Sierra, and only including ones in Foundation and CoreFoundation

Strings:

_NSCFString - a CFStringRef or CFMutableStringRef. This is the most common type of string object currently.
    - May have 8 bit (ASCII) or 16 bit (UTF-16) backing store
_NSCFConstantString - a compile time constant CFStringRef, like you'd get with @"foo"
    - May also be generated by dynamic string creation if matches a string in a pre-baked table of common strings called the StringROM
NSBigMutableString - an NSString backed by a CFStorage (https://github.com/opensource-apple/CF/blob/master/CFStorage.h) for faster handling of very large strings
NSCheapMutableString - a very limited NSMutableString that allows for zero-copy initialization. Used in NSFileManager for temporarily wrapping stack buffers.

VojtaStavik

import UIKit

class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

  @IBOutlet weak var tableView: UITableView!

  override func viewDidLoad() {
    super.viewDidLoad()
    NSLayoutConstraint.activate([
      tableView.topAnchor.constraint(equalTo: view.topAnchor),

chriseidhof

import Foundation

// Alternatives to `Scanner` (before: `NSScanner`).


// A scanner only needs a way to peek and to move to the next token.
protocol ScannerProtocol {
    associatedtype Token: Equatable
    var peek: Token? { get }
    mutating func moveToNextToken()

nicklockwood

// This is a really simple drop-in replacement for String.UnicodeScalarView
// As of Swift 3.2, String.UnicodeScalarView no longer supports slice operations, and
// String.UnicodeScalarView.Subsequence is ~5x slower
//
// Only a small subset of methods are implemented, specifically the ones useful for
// implementing a parser or lexer that consumes a string by repeatedly calling popFirst()
//
// I've benchmarked popFirst() as ~7x faster than String.UnicodeScalarView.Subsequence in Swift 3.2 and 4.0
// The performance is close to that of String.UnicodeScalarView in Swift 3.1, but may be slightly worse in some use cases

JohnSundell

import Foundation

struct EquatableValueSequence<T: Equatable> {
    static func ==(lhs: EquatableValueSequence<T>, rhs: T) -> Bool {
        return lhs.values.contains(rhs)
    }

    static func ==(lhs: T, rhs: EquatableValueSequence<T>) -> Bool {
        return rhs == lhs
    }

chriseidhof

/*:
 
 This is an implementation of Algorithm W, as found in [Principal Types for functional programs](http://web.cs.wpi.edu/~cs4536/c12/milner-damas_principal_types.pdf).
 
 We'll start by defining literals and expressions:
 */

enum Literal {
    case string(String)
    case int(Int)