Yerassyl Zhassuzakhov Yerazhas

Threads

Foundation offers a Thread class, internally based on pthread, that can be used to create new threads and execute closures.

// Detaches a new thread and uses the specified selector as the thread entry point.
Thread.detachNewThreadSelector(selector: Selector>, toTarget: Any, with: Any)

// Subclass
class MyThread: Thread {

Compile Time Constant Expressions for Swift

Proposal: SE-NNNN
Authors: Marc Rasi, Chris Lattner
Review Manager: TBD
Status: Awaiting implementation

Swift-evolution thread: https://forums.swift.org/t/pitch-compile-time-constant-expressions-for-swift/12879

Introduction

libdispatch efficiency tips

The libdispatch is one of the most misused API due to the way it was presented to us when it was introduced and for many years after that, and due to the confusing documentation and API. This page is a compilation of important things to know if you're going to use this library. Many references are available at the end of this document pointing to comments from Apple's very own libdispatch maintainer (Pierre Habouzit).

My take-aways are:

You should create very few, long-lived, well-defined queues. These queues should be seen as execution contexts in your program (gui, background work, ...) that benefit from executing in parallel. An important thing to note is that if these queues are all active at once, you will get as many threads running. In most apps, you probably do not need to create more than 3 or 4 queues.
Go serial first, and as you find performance bottle necks, measure why, and if concurrency helps, apply with care, always validating under system pressure. Reuse

The metatypes explanation

For every type T in Swift, there is an associated metatype T.Type.

Basics: function specialization

Let's try to write a generic function like staticSizeof. We will only consider its declaration; implementation is trivial and unimportant here.

Out first try would be:

	import SwiftUI

	extension Calendar {
	func generateDates(
	inside interval: DateInterval,
	matching components: DateComponents
	) -> [Date] {
	var dates: [Date] = []
	dates.append(interval.start)

	1. Очень крутая книжка по сетям (стек OSI) – Charles Severance “Introduction to Network: How the Internet works”
	2. URLCache – https://nshipster.com/nsurlcache/
	3. Ресёрч HTTP-кеширования с использованием URLCache https://qnoid.com/2016/04/10/A-primer-in-HTTP-caching-and-its-native-support-by-iOS.html
	4. Анализ доступности сети:
	* SimplePing – https://developer.apple.com/library/archive/samplecode/SimplePing/Introduction/Intro.html
	* https://github.com/dustturtle/RealReachability
	* https://github.com/ankitthakur/SwiftPing
	* https://github.com/lmirosevic/GBPing
	* https://github.com/rwbutler/Connectivity
	* Баг с 2009 года – https://lists.apple.com/archives/macnetworkprog/2009/May/msg00056.html

	import UIKit

	/// A validation rule for text input.
	public enum TextValidationRule {
	/// Any input is valid, including an empty string.
	case noRestriction
	/// The input must not be empty.
	case nonEmpty
	/// The enitre input must match a regular expression. A matching substring is not enough.
	case regularExpression(NSRegularExpression)

	//: 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)
	}

	let color = "blue"
	let num = 42

	localized("Colorless green ideas sleep furiously.")
	localized("Colorless \(color) ideas sleep furiously.")
	localized("\(num.formatted("%05d")) colorless green ideas sleep furiously.")

	1. Open Terminal
	2. cd to your Xcode project
	3. Execute the following when inside your target project:

	find . -name "*.swift" -print0 \| xargs -0 wc -l