Dmitriy Tukhtamanov cocavo

If you work on a Swift project that follows the Model-View-ViewModel (MVVM) architecture or similar, you may want to jump to counterpart in Xcode from your view to your model, and then to your view model. (ie. by using Ctrl+Cmd+Up and Ctrl+Cmd+Down).

You can do this in recent versions of Xcode by setting a configuration default.

From a terminal, just type this command and press Enter:

defaults write com.apple.dt.Xcode IDEAdditionalCounterpartSuffixes -array-add "ViewModel" "View"

Why COW was deemed ungood for std::string.

COW, short for copy on write, is a way to implement mutable strings so that creating strings and logically copying strings, is reduced to almost nothing; conceptually they become free operations like no-ops.

Basic idea: to share a data buffer among string instances, and only make a copy for a specific instance (the copy on write) when that instance's data is modified. The general cost of this is only an extra indirection for accessing the value of a string, so a COW implementation is highly desirable. And so the original C++ standard, C++98, and its correction C++03, had special support for COW implementations, and e.g. the g++ compiler's std::string implementations used COW.

So why was that support dropped in C++11?

In particular, would the same reason or reasons apply to a reference counted immutable string value class?

Building network actors with Node Framework

Article topics:

What is Node Framework?
Sample nodes
Node Framework languages structure
- Core languages
- Framework languages
Node Framework design and architecture

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

Moved to https://github.com/kbilsted/Functional-core-imperative-shell/blob/master/README.md

Notes on Apple’s Under-Documented LaunchD

Start triggers fire regardless of other conditions

For example, StartOnMount=true will cause the job to start when anything is mounted even if other conditions, e.g. QueueDirectories, say the job should not run

Rhythm of repeating jobs

The StartInterval timer begins ticking at the moment the plist is loaded. If something like QueueDirectories is preventing the job from

	import UIKit

	#if canImport(SwiftUI) && DEBUG
	import SwiftUI
	struct UIViewControllerPreview<ViewController: UIViewController>: UIViewControllerRepresentable {
	let viewController: ViewController

	init(_ builder: @escaping () -> ViewController) {
	viewController = builder()
	}

	// For the best results, your tableHeaderView/tableFooterView should be a UITableViewHeaderFooterView with your content inside the contentView.
	let tableHeaderView = UITableViewHeaderFooterView()

	let fittingSize = CGSize(width: tableView.bounds.width - (tableView.safeAreaInsets.left + tableView.safeAreaInsets.right), height: 0)
	let size = tableHeaderView.systemLayoutSizeFitting(fittingSize, withHorizontalFittingPriority: .required, verticalFittingPriority: .fittingSizeLevel)
	tableHeaderView.frame = CGRect(origin: .zero, size: size)
	tableView.tableHeaderView = tableHeaderView

	// When you set this view to the tableHeaderView/tableFooterView on the table view, the table view will preserve the existing size of its frame.
	// If you need to change the size, remove the tableHeaderView/tableFooterView, set a new frame on it, then re-set it on the table view again.

	https://developer.apple.com/videos/wwdc/2015/?id=101 101 Keynote
	https://developer.apple.com/videos/wwdc/2015/?id=102 102 Platforms State of the Union
	https://developer.apple.com/videos/wwdc/2015/?id=103 103 Apple Design Awards
	https://developer.apple.com/videos/wwdc/2015/?id=104 104 What's New in Xcode
	https://developer.apple.com/videos/wwdc/2015/?id=105 105 Introducing WatchKit for watchOS 2
	https://developer.apple.com/videos/wwdc/2015/?id=106 106 What's New in Swift
	https://developer.apple.com/videos/wwdc/2015/?id=107 107 What's New in Cocoa Touch
	https://developer.apple.com/videos/wwdc/2015/?id=108 108 Building Watch Apps
	https://developer.apple.com/videos/wwdc/2015/?id=112 112 Think Audacious
	https://developer.apple.com/videos/wwdc/2015/?id=201 201 iOS Accessibility