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What’s new in Swift 5.3?

Swift 5.3 goes to be an thrilling new launch. This submit is a showcase of the newest Swift programming language options.


The Swift 5.3 launch course of began in late March, there are many new options which might be already applied on the 5.3 department. In case you are curious what are these you possibly can strive it out by putting in the newest snapshot utilizing swiftenv for instance, you possibly can seize them from

Bundle Supervisor updates

Swift Bundle instruments model 5.3 will function some actually nice additions.


With the implementation of SE-0271 the Swift Bundle Supervisor can lastly bundle useful resource recordsdata alongside code. I consider that this was fairly a well-liked request, since there are some libraries that embed asset recordsdata, they weren’t in a position so as to add SPM help, till now.

Localized assets

SE-0278 extends the useful resource help, with this implementation you possibly can declare localized assets to your Swift packages. The outline explains nicely the proposed construction, it’s best to have a look if you’re fascinated about delivery localized recordsdata along with your package deal.

Binary dependencies

The opposite great point is that SPM will lastly have the ability to use binary dependencies. SE-0272 provides this functionality so individuals who wish to ship closed supply code can now benefit from this function. This may make it doable to have a binaryTarget dependency at a given path or location and you should use the binary as a product in a library or executable.

Conditional Goal Dependencies

SE-0273 offers us a pleasant little addition so we will use dependencies primarily based on given platforms. Which means you should use a product for a goal if you construct for a selected platform.

These options are nice additions to the SPM, hopefully Xcode will profit from these items as nicely, and we’ll see some nice new enhancements within the upcoming model of the IDE too.

Language options

There are various new attention-grabbing proposals that received into the 5.3 model.

A number of Trailing Closures

SE-0279 is among the most debated new proposal. Once I first noticed it I used to be unsure in regards to the want of it, why would somebody put a lot effort to get rid of a couple of brackets? 🤔

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {

        UIView.animate(withDuration: 0.3, animations: {
          self.view.alpha = 0
        }, completion: { _ in
        UIView.animate(withDuration: 0.3, animations: {
          self.view.alpha = 0
        }) { _ in

        UIView.animate(withDuration: 0.3) {
          self.view.alpha = 0
        UIView.animate(withDuration: 0.3) {
            self.view.alpha = 0
        } completion: { _ in

As you possibly can see that is principally a syntactic sugar, however I satisfied myself that it’s good to have.

Synthesized Comparable conformance for enum sorts

Enum sorts do not should explicitly implement the Comparable protocol because of SE-0266.

enum Membership: Comparable {
    case premium(Int)
    case most well-liked
    case basic
([.preferred, .premium(1), .general, .premium(0)] as [Membership]).sorted()

The Comparable protocol is mechanically synthesized, identical to the Equatable and Hashable conformances for eligible sorts. After all you possibly can present your individual implementation if wanted.

Enum instances as protocol witnesses

Swift enums are loopy highly effective constructing blocks and now they only received higher. 💪

protocol DecodingError {
  static var fileCorrupted: Self { get }
  static func keyNotFound(_ key: String) -> Self

enum JSONDecodingError: DecodingError {
  case fileCorrupted
  case keyNotFound(_ key: String)

The primary aim of SE-0280 to elevate an present restriction, this manner enum instances will be protocol witnesses if they supply the identical case names and arguments because the protocol requires.

Sort-Based mostly Program Entry Factors

SE-0281 offers us a brand new @primary attribute that you should use to outline entry factors to your apps. This can be a welcome addition, you do not have to put in writing the MyApp.primary() methodology anymore, however merely mark the MyApp object with the principle attribute as a substitute.

class AppDelegate: UIResponder, UIApplicationDelegate {

    static func primary() {
        print("App will launch & exit instantly.")

The UIApplicationMain and NSApplicationMain attributes might be deprecated in favor of @primary, I might wager that is coming with the following main launch…

Multi-Sample Catch Clauses

SE-0276 is one other syntactic sugar, it is actually useful to catch a number of instances without delay.

do {
    strive performTask()
catch TaskError.someRecoverableError {
    get better()
catch TaskError.someFailure(let msg), TaskError.anotherFailure(let msg) {

This eliminates the necessity of utilizing a change case within the catch block. ✅


Nothing a lot to say right here, SE-0277 provides Float16 to the usual library.

let f16: Float16 = 3.14

Generic math features are additionally coming quickly…

Self adjustments

SE-0269 aka. Enhance availability of implicit self in @escaping closures when reference cycles are unlikely to happen is a pleasant addition for many who do not like to put in writing self. 🧐

execute {
    let foo = self.doFirstThing()
    self.doSecondThing(with: foo)

execute { [self] in
    let foo = doFirstThing()
    performWork(with: bar)
    doSecondThing(with: foo)

This may enable us to put in writing self within the seize record solely and omit it afterward contained in the block.

Refine didSet Semantics

SE-0268 is an below the hood enchancment to make didSet conduct higher & extra dependable. 😇

class Foo {
    var bar = 0 {
        didSet { print("didSet referred to as") }

    var baz = 0 {
        didSet { print(oldValue) }

let foo = Foo() = 1

foo.baz = 2

In a nutshell beforehand the getter of a property was all the time referred to as, however any further it will be solely invoked if we use to the oldValue parameter in our didSet block.

Add Assortment Operations on Noncontiguous Parts

SE-0270 provides a RangeSet sort for representing a number of, noncontiguous ranges, in addition to a wide range of assortment operations for creating and dealing with vary units.

var numbers = Array(1...15)

let indicesOfEvens = numbers.subranges(the place: { $0.isMultiple(of: 2) })

let sumOfEvens = numbers[indicesOfEvens].scale back(0, +)

let rangeOfEvens = numbers.moveSubranges(indicesOfEvens, to: numbers.startIndex)

This proposal additionally extends the Assortment sort with some API strategies utilizing the RangeSet sort, it’s best to have a look if you’re working rather a lot with ranges. 🤓

The place clauses on contextually generic declarations

With SE-0267 you’ll implement features and put a the place constraint on them if you’re solely referencing generic parameters. Think about the next snippet:

protocol P {
    func foo()

extension P {
    func foo() the place Self: Equatable {

This may not compile on older variations, but it surely’ll work like magic after Swift 5.3.

Add a String Initializer with Entry to Uninitialized Storage

SE-0263 provides a brand new String initializer that permits you to work with an uninitialized buffer.

let myCocoaString = NSString("The fast brown fox jumps over the lazy canine") as CFString
var myString = String(unsafeUninitializedCapacity: CFStringGetMaximumSizeForEncoding(myCocoaString, ...)) { buffer in
    var initializedCount = 0
    return initializedCount

By utilizing this new init methodology you do not have to fiddle with unsafe pointers anymore.

Future evolution of Swift

At the moment there are 6 extra accepted proposals on the Swift evolution dasboard and one is below overview. Swift 5.3 goes to include some wonderful new options that have been lengthy awaited by the neighborhood. I am actually joyful that the language is evolving in the correct path. 👍



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