Erik Flores erikfloresq

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.

FastScrollingCollectionView

UICollectionView with optimized smooth scrolling and improved performance.

I expect that you use this when you want to add UICollectionView displaying images to your app.

Tips

1. Cache image

We can use SDWebImage. Standing on the shoulders of giants.

	//: Playground - noun: a place where people can play

	import UIKit

	protocol SectionModel {
	var count: Int { get }

	func cell(at: Int) -> UITableViewCell
	func selected(at: Int)
	}

	#!/usr/bin/env ruby

	print "What is the URL of your Apple Downloads resource?\nURL:"
	url = gets.strip

	print "What is the ADCDownloadAuth cookie token:\nADCDownloadAuth: "
	token = gets.strip

	command = "aria2c --header \"Host: adcdownload.apple.com\" --header \"Accept: text/html,application/xhtml+xml,application/xml;q=0.9,/;q=0.8\" --header \"Upgrade-Insecure-Requests: 1\" --header \"Cookie: ADCDownloadAuth=#{token}\" --header \"User-Agent: Mozilla/5.0 (iPhone; CPU iPhone OS 10_1 like Mac OS X) AppleWebKit/602.2.14 (KHTML, like Gecko) Version/10.0 Mobile/14B72 Safari/602.1\" --header \"Accept-Language: en-us\" -x 16 -s 16 #{url} -d ~/Downloads"

	// First, install InjectionIII.app from the Mac AppStore
	// https://apps.apple.com/us/app/injectioniii/id1380446739?mt=12

	// Make these changes to your code:

	// add the following to application(didFinishLaunchingWithOptions:)
	#if DEBUG
	Bundle(path: "/Applications/InjectionIII.app/Contents/Resources/iOSInjection.bundle")?.load()
	#endif

	import UIKit

	/// Represents a single `NSLayoutConstraint`
	enum LayoutAnchor {
	case constant(attribute: NSLayoutConstraint.Attribute,
	relation: NSLayoutConstraint.Relation,
	constant: CGFloat)

	case relative(attribute: NSLayoutConstraint.Attribute,
	relation: NSLayoutConstraint.Relation,