lattner

Async/Await for Swift

• Proposal: SE-XXXX
• Authors: Chris Lattner, Joe Groff

Introduction

Modern Cocoa development involves a lot of asynchronous programming using closures and completion handlers, but these APIs are hard to use. This gets particularly problematic when many asynchronous operations are used, error handling is required, or control flow between asynchronous calls gets complicated. This proposal describes a language extension to make this a lot more natural and less error prone.

This paper introduces a first class Coroutine model to Swift. Functions can opt into to being async, allowing the programmer to compose complex logic involving asynchronous operations, leaving the compiler in charge of producing the necessary closures and state machines to implement that logic.

DougGregor

extension Collection {
  func parallelMap<T>(
    parallelism requestedParallelism: Int? = nil,
    _ transform: @escaping (Element) async throws -> T
  ) async throws -> [T] {
    let defaultParallelism = 2
    let parallelism = requestedParallelism ?? defaultParallelism

    let n = self.count
    if n == 0 {

steipete

# The trick is to link the DeviceSupport folder from the beta to the stable version.
# sudo needed if you run the Mac App Store version. Always download the dmg instead... you'll thank me later :)

# Support iOS 15 devices (Xcode 13.0) with Xcode 12.5:
sudo ln -s /Applications/Xcode-beta.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport/15.0 /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/DeviceSupport

# Then restart Xcode and reconnect your devices. You will need to do that for every beta of future iOS versions

# (A similar approach works for older versions too, just change the version number after DeviceSupport)

davbeck

import Combine
import SwiftUI
import WebKit

@Observable final class WebViewContent: NSObject {
	let id = UUID()

	var url: URL?

	var title: String?

davbeck

import Foundation

// Foundation.CharacterSet should be called "UnicodeScalarSet"
// this operates on actual Characters

// TODO: Equatable doesn't work right: for instance defining a range vs defining a set with the same values will not be equal

indirect enum CharacterSet: Sendable, Hashable {
    case closedRange(ClosedRange<Character>)
    case set(Set<Character>)

davbeck

#pragma mark - WKUIDelegate

- (void)webView:(WKWebView *)webView runJavaScriptAlertPanelWithMessage:(NSString *)message initiatedByFrame:(WKFrameInfo *)frame completionHandler:(void (^)())completionHandler
{
    UIAlertController *alert = [UIAlertController alertControllerWithTitle:nil
                                                                   message:message
                                                            preferredStyle:UIAlertControllerStyleAlert];
    
    [alert addAction:[UIAlertAction actionWithTitle:NSLocalizedString(@"OK", nil) style:UIAlertActionStyleCancel handler:^(UIAlertAction *action) {
        completionHandler();

davbeck

#!/usr/bin/env ruby

require "active_support"


def assetCatalogsAtPath(path)
	results = []
	
  contents = Dir.entries(path)
  

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) {

uliluckas

// See http://lists.apple.com/archives/cocoa-dev/2008/Jun/msg00237.html for bugs below
- (void)mergeChangesFromContextDidSaveNotification:(NSNotification*)notification {
    NSManagedObject *object;
    NSSet* updates;
    
	// Workaround bug 5982319
    // Fault in all updated objects because chnages to faults won't trigger fetchedResultsControlle
    updates = [notification.userInfo objectForKey:NSUpdatedObjectsKey];
	for (object in updates) {
		[[self.roManagedObjectContext objectWithID:[object objectID]] willAccessValueForKey:nil];

ketzusaka

/*
In Swift, you can overload operators. A common operator in Ruby for working with arrays is <<, 
which is syntatic sugar for array.push(). Since Array's in Swift don't take bitwise operations, this is
an example demonstrating adding that operator to an array that contains any type.

As an extra tidbit, I've added >> to prepend an array with an object
*/

@infix func << <T>(inout array: Array<T>, item: T) {
    array.append(item)