Tyler haikusw

Today I wanted to move existing APFS-resident macOS Catalina installation to a new disk. I upgraded my late 2014 Mac Mini with a shiny new 1TB SSD. This took way too many hours of my life I will never get back. Hope this saves some time to you.

Good news:

it is possible to create a DMG image from existing APFS container with macOS Catalina installation including metadata needed for complete restore (the DMG contains OS, OS Data, Preboot, Recovery and VM volumes)
it is possible to restore this DMG image into empty APFS container and get a bootable copy of the original system

This information is relevant for Catalina (I'm currently running macOS 10.15.1).

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

State of String: ABI, Performance, Ergonomics, and You!

Hello, I’ve been working on implementing, optimizing, and improving String in preparation for ABI stability, and I thought I’d share the current status of String in Swift 5 and some potential directions to go. This is the product of conversations with open source contributors and my colleagues on the Swift standard library team at Apple.

The primary area of focus is stabilizing String’s ABI, but we’d be remiss if we couldn’t also fit in performance and ergonomic improvements. String’s ergonomics in particular is one area where we think the status quo is woefully inadequate, and over half of this email is devoted to that topic. At the end, there’s a section about a community initiative that we hope can help users of String as well as guide future development.

(Note: I’m sending this to swift-dev because much of the contents revolve around implementation concerns. I’ll also cross-reference on swift-evolution and swift-users. See also the [StringManife

	/*:
	Joe Groff:

	> In a lot of the ways people use dictionaries/maps/hashtables, there's a type dependency between
	> the keys and values, but most mainstream typed languages provide homogeneously-typed maps.
	> Are there any that try to preserve more interesting type relationships between key and value?
	> https://twitter.com/jckarter/status/1278739951568314368

	> As one example, it's common for specific keys to be associated with specific types, like in
	> {"name": "Tanzy", "age": 13}, "name" should always map to a string, and "age" to a number.

	# A Best in Class Checklist
	A boiled down checklist adapted from this [post](https://www.swiftjectivec.com/a-best-in-class-app/), created by @jordanmorgan10.

	> To use this, create a Github Issue in your own repo, and simply copy and paste this text.

	## iOS Core Technology
	_Things any iOS app can benefit from_

	- [ ] iCloud Sync
	- [ ] Focus Filter Support

	protocol KeyPathUpdatable {}

	extension KeyPathUpdatable {
	func updating<LeafType>(_ keyPath: WritableKeyPath<Self, LeafType>, to value: LeafType) -> Self {
	var copy = self
	copy[keyPath: keyPath] = value
	return copy
	}
	}

	extension FileManager {
	/*
	Prints out the locations of the simulator and the shared group folder.
	This is useful for debugging file issues.

	Example usage: FileManager.default.printFileLocations()
	*/
	func printFileLocations() {
	let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
	let simulatorFolder = paths.last!

	import SwiftUI
	import UIKit

	struct PageViewController: UIViewControllerRepresentable {
	var controllers: [UIViewController]
	@Binding var currentPage: Int

	func makeCoordinator() -> Coordinator {
	Coordinator(self)
	}

	//
	// ContentView.swift
	// AnimationTimingCurve
	//
	// Created by Chris Eidhof on 25.09.19.
	// Copyright © 2019 Chris Eidhof. All rights reserved.
	//

	import SwiftUI

	extension UIView {
	/// Example: call someView.nudge(0, 30)
	func nudge(_ dx: CGFloat, _ dy: CGFloat) {
	self.frame = self.frame.offsetBy(dx: dx, dy: dy)
	CATransaction.flush()
	}
	}

	extension UIView {
	/// Example: po UIView.root