Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Swift 4 Highlights
Search
Jonathan Lehr
March 05, 2018
Programming
2
290
Swift 4 Highlights
Presentation given at Capital One in McLean, VA, March 5, 2018
Jonathan Lehr
March 05, 2018
Tweet
Share
More Decks by Jonathan Lehr
See All by Jonathan Lehr
Transitioning to Swift
jonathanlehr
0
150
Other Decks in Programming
See All in Programming
Async Await: Mastering Python's Time-Bending Tricks - EuroPython2024
yanbo
1
290
OpenAI/Gemini APIを使って EPUBを翻訳するCLIツールをつくってみた
tomiyan
0
790
CSC307 Lecture 12
javiergs
PRO
0
220
みんなのオブザーバビリティプラットフォームを作ってるんだがパフォーマンスがやばい #mackerelio #srenext
ne_sachirou
0
380
DynamoDB コスト最適化っぽいことの基本 with Terraform
kuro_kurorrr
2
250
入社1ヶ月でここまでやった!Findy Toolsインフラ支援の最適化
rvirus0817
6
1.4k
TiDB Serverless ~理想のServerless DBを考える~
soso_15315
1
160
継続的な活動で築く地方エンジニアの道
myamashii
2
360
I/O Extended Android in Korea 2024 ~ Whats new in Android development tools
pluu
0
250
【Go言語】golangci-lintの使い方
tomo1227
0
280
Modern Angular: Renovation for Your Applications
manfredsteyer
PRO
0
140
유연한 Composable 설계
l2hyunwoo
0
380
Featured
See All Featured
Become a Pro
speakerdeck
PRO
15
4.8k
Unsuck your backbone
ammeep
666
57k
Designing for Performance
lara
604
67k
Why You Should Never Use an ORM
jnunemaker
PRO
51
8.9k
CSS Pre-Processors: Stylus, Less & Sass
bermonpainter
353
29k
ピンチをチャンスに:未来をつくるプロダクトロードマップ #pmconf2020
aki_iinuma
90
47k
Designing on Purpose - Digital PM Summit 2013
jponch
113
6.6k
Product Roadmaps are Hard
iamctodd
PRO
48
10k
Bootstrapping a Software Product
garrettdimon
PRO
304
110k
Fight the Zombie Pattern Library - RWD Summit 2016
marcelosomers
228
16k
Writing Fast Ruby
sferik
623
60k
The Invisible Customer
myddelton
117
13k
Transcript
ABOUTOBJECTS Swi$ 4 Highlights Jonathan Lehr, Founder and VP, Training
1
About Objects • Reston, VA • Full-stack consul3ng (NFL, Marrio;,
Chicos, etc.) and training • Strong focus on iOS and middleware • Roots in NeXT, OpenStep, WebObjects + enterprise backends 2
Resources GitHub.com/AboutObjectsTraining • Swi% 4 Highlights • Swi% 3 Lowlights
Ole Begemann (oleb.net/blog) • Playground: What's new in Swi7 4 Copyright © 2018, About Objects, Inc. 3
Swi$ 4 Overview Copyright © 2018, About Objects, Inc. 4
New/Enhanced in Swi. 4 • Strings and One-Sided Ranges •
Collec4ons • Dictionary • Set • Key-Value Coding • Codable Protocol and JSON Support Copyright © 2018, About Objects, Inc. 5
Migra&ng From Swi. 3 • Explicit @obj direc-ves required on
a per-method basis to enable dynamic dispatch • Some Swi< 4 String APIs now return a new type, Substring Copyright © 2018, About Objects, Inc. 6
Strings 7
Strings in Swi* 2 and Swi* 3 • Dropped Collection
conformance • Added characters property containing collec4on of Character (extended grapheme cluster) • Substrings referred to original string's storage • ✅ Very efficient • ❌ Poten4al memory leak Copyright © 2018, About Objects, Inc. 8
Swi$ 3 String API Clutziness let stars = "✭✭✭✭✭✩✩✩✩✩" let
charView1 = stars.characters.dropFirst(2) print(charView1) // CharacterView(_core: // Swift._StringCore(_baseAddress: Optional(0x0000000101362454), // _countAndFlags: 9223372036854775816, _owner: nil), _coreOffset: 2) let charView2 = charView1.dropLast(3) // Still a CharacterView ! print(String(charView2)) // ✭✭✭✩✩ // Swift 4 print(stars.dropFirst(2).dropLast(3)) // ✭✭✭✩✩ Copyright © 2018, About Objects, Inc. 9
Swi$ 3 String API Clutziness let stars = "✭✭✭✭✭✩✩✩✩✩" let
charView1 = stars.characters.dropFirst(2) print(charView1) // CharacterView(_core: // Swift._StringCore(_baseAddress: Optional(0x0000000101362454), // _countAndFlags: 9223372036854775816, _owner: nil), _coreOffset: 2) let charView2 = charView1.dropLast(3) // Still a CharacterView ! print(String(charView2)) // ✭✭✭✩✩ // Swift 4 print(stars.dropFirst(2).dropLast(3)) // ✭✭✭✩✩ Copyright © 2018, About Objects, Inc. 10
Swi$ 3 String API Clutziness let stars = "✭✭✭✭✭✩✩✩✩✩" let
charView1 = stars.characters.dropFirst(2) print(charView1) // CharacterView(_core: // Swift._StringCore(_baseAddress: Optional(0x0000000101362454), // _countAndFlags: 9223372036854775816, _owner: nil), _coreOffset: 2) let charView2 = charView1.dropLast(3) // Still a CharacterView ! print(String(charView2)) // ✭✭✭✩✩ // Swift 4 print(stars.dropFirst(2).dropLast(3)) // ✭✭✭✩✩ Copyright © 2018, About Objects, Inc. 11
Swi$ 4 Strings (SE-0163) • Adds back Collection conformance and
deprecates characters property • Adds Substring type • Prevents leaks by helping developers avoid accidental storage of Substring instances • String and Substring share API by conforming to StringProtocol Copyright © 2018, About Objects, Inc. 12
String Collec-on API Examples // Looping through a string's characters:
let s = "abc" for c in s { print(c) } // a // b // c // Inserting characters: var name = "Fred Smith" let index = name.index(of: " ") ?? name.endIndex name.insert(contentsOf: " W.", at: index) // Fred W. Smith Copyright © 2018, About Objects, Inc. 13
String Collec-on API Examples // Looping through a string's characters:
let s = "abc" for c in s { print(c) } // a // b // c // Inserting characters: var name = "Fred Smith" let index = name.index(of: " ") ?? name.endIndex name.insert(contentsOf: " W.", at: index) // Fred W. Smith Copyright © 2018, About Objects, Inc. 14
Substring Example let name = "Fred Smith" let last: Substring
= name.dropFirst(5) // type ^^^^^^^^^^^ shown for clarity print(last) // "Smith" struct Dude { var name: String? } var dude = Dude() dude.name = name // ! Doesn't compile Copyright © 2018, About Objects, Inc. 15
Substring Example let name = "Fred Smith" let last: Substring
= name.dropFirst(5) // type ^^^^^^^^^^^ shown for clarity print(last) // "Smith" struct Dude { var name: String? } var dude = Dude() dude.name = name // ! Doesn't compile Copyright © 2018, About Objects, Inc. 16
Mul$-Line String Literals (SE-168) • Enclosed in triple-quotes • Whitespace
up to trailing quotes ignored let year = 2017 let numPages = 240 let jsonText = """ { "title": "War of the Worlds", "author": "H. G. Wells", "publication_year": \(year), "number_of_pages": \(numPages) } """ Copyright © 2018, About Objects, Inc. 17
One-Sided Ranges (SE-172) • Ranges can be expressed without explicit
star6ng or ending values let s = "Hello !!" // Compute an index relative to start of string. let index = s.index(s.startIndex, offsetBy: 6) let head = s[..<index] print(head) // "Hello " let tail = s[index...] print(tail) // "!!" Copyright © 2018, About Objects, Inc. 18
Collec&ons 19
Dic$onary Keys and Values (SE-154) • Adds type-specific collec0ons for
keys and values • Faster key lookups • More effecient value muta0on let books = ["Emma": 11.95, "Henry V": 14.99, "1984": 14.99, "Utopia": 11.95] guard let index = books.index(forKey: "Emma") else { return } print(books.values[index]) // 11.95 Copyright © 2018, About Objects, Inc. 20
Dic$onary & Set Enhancements(SE-165) • Dic%onary-specific map and filter •
Grouping sequence elements • Default values for subscripts • Merging dic%onaries Copyright © 2018, About Objects, Inc. 21
Dic$onary-Specific Filter let books = ["Emma": 11.95, "Henry V": 14.99,
"1984": 14.99, "Utopia": 11.95] // In Swift 3, Dictionary's `filter` method returned an // array of key-value tuples instead of a dictionary. let cheapBooks = books.filter { $0.value < 12.00 } // [(key: "Utopia", value: 11.95), (key: "Emma", value: 11.95)] // If you need a Dictionary result, you have to produce one manually let cheapBooksDict = cheapBooks.reduce([:]) { var dict = $0 dict[$1.key] = $1.value return dict } // ["Utopia": 11.95, "Emma": 11.95] Copyright © 2018, About Objects, Inc. 22
Dic$onary-Specific Filter let books = ["Emma": 11.95, "Henry V": 14.99,
"1984": 14.99, "Utopia": 11.95] // In Swift 3, Dictionary's `filter` method returned an // array of key-value tuples instead of a dictionary. let cheapBooks = books.filter { $0.value < 12.00 } // ["Utopia": 11.95, "Emma": 11.95] // If you need a Dictionary result, you have to produce one manually let cheapBooksDict = cheapBooks.reduce([:]) { var dict = $0 dict[$1.key] = $1.value return dict } // ["Utopia": 11.95, "Emma": 11.95] Copyright © 2018, About Objects, Inc. 23
Dic$onary-Specific Map let books = ["Emma": 11.95, "Henry V": 14.99,
"1984": 14.99, "Utopia": 11.95] // Similarly, Dictionary's `map` method returns an array of values let discount = 0.10 let discountedPrices = books.map { $0.value * (1 - discount) } // [10.75, 13.49, 10.75, 13.49] // That's fine if you simply want to sum the values, but suppose // you want to produce a list of discounted prices? // Swift 4 adds `mapValues`, which returns a Dictionary let discount = 0.10 let discountedBooks = books.mapValues { $0 * (1 - discount) } // ["Utopia": 10.75, "1984": 13.49, "Emma": 10.75, "Henry V": 13.49] Copyright © 2018, About Objects, Inc. 24
Dic$onary-Specific Map let books = ["Emma": 11.95, "Henry V": 14.99,
"1984": 14.99, "Utopia": 11.95] // Similarly, Dictionary's `map` method returns an array of values let discount = 0.10 let discountedPrices = books.map { $0.value * (1 - discount) } // [10.75, 13.49, 10.75, 13.49] // That's fine if you simply want to sum the values, but suppose // you want to produce a list of discounted prices? // Swift 4 adds `mapValues`, which returns a Dictionary let discount = 0.10 let discountedBooks = books.mapValues { $0 * (1 - discount) } // ["Utopia": 10.75, "1984": 13.49, "Emma": 10.75, "Henry V": 13.49] Copyright © 2018, About Objects, Inc. 25
Dic$onary-Specific Map let books = ["Emma": 11.95, "Henry V": 14.99,
"1984": 14.99, "Utopia": 11.95] // Similarly, Dictionary's `map` method returns an array of values let discount = 0.10 let discountedPrices = books.map { $0.value * (1 - discount) } // [10.75, 13.49, 10.75, 13.49] // That's fine if you simply want to sum the values, but suppose // you want to produce a list of discounted prices? // Swift 4 adds `mapValues`, which returns a Dictionary let discount = 0.10 let discountedBooks = books.mapValues { $0 * (1 - discount) } // ["Utopia": 10.75, "1984": 13.49, "Emma": 10.75, "Henry V": 13.49] Copyright © 2018, About Objects, Inc. 26
Grouping Sequence Elements • Swi% 4 adds a new ini-alizer
for grouping sequences of values. ! let books = ["Emma": 11.95, "Henry V": 14.99, "1984": 14.99, "Utopia": 11.95] let booksByPrice = Dictionary(grouping: books, by: { $0.value }) // [11.95: [(key: "Utopia", value: 11.95), // (key: "Emma", value: 11.95)], // 14.99: [(key: "1984", value: 14.99), // (key: "Henry V", value: 14.99)]] Copyright © 2018, About Objects, Inc. 27
Default Values for Subscripts // Access with default value may
not seem like a huge win let books = ["Emma": 11.95, "Henry V": 14.99, "1984": 14.99, "Utopia": 11.95] // Swift 3: let price = books["Foo"] ?? 0 // Swift 4: let price2 = books["Foo", default: 0] // ...but mutation with a default value is ! var discountedBooks = books let keys = ["Emma", "1984", "Foo"] for key in keys { discountedBooks[key, default: 0] *= 0.9 } // ["Utopia": 11.95, "1984": 13.49, "Foo": 0.0, "Emma": 10.75, "Henry V": 14.99] Copyright © 2018, About Objects, Inc. 28
Default Values for Subscripts // Access with default value may
not seem like a huge win let books = ["Emma": 11.95, "Henry V": 14.99, "1984": 14.99, "Utopia": 11.95] // Swift 3: let price = books["Foo"] ?? 0 // Swift 4: let price2 = books["Foo", default: 0] // ...but mutation with a default value is ! var discountedBooks = books let keys = ["Emma", "1984", "Foo"] for key in keys { discountedBooks[key, default: 0] *= 0.9 } // ["Utopia": 11.95, "1984": 13.49, "Foo": 0.0, "Emma": 10.75, "Henry V": 14.99] Copyright © 2018, About Objects, Inc. 29
Merging Dic*onaries let personal = ["home": "703-333-4567", "cell": "202-444-1234"] let
work = ["main": "571-222-9876", "cell": "703-987-5678"] // If keys match, replaces the current value with the newer value var phones1 = personal phones1.merge(work) { _, new in new } ["main": "571-222-9876", "cell": "703-987-5678", "home": "703-333-4567"] // If keys match, replaces the current value with a tuple of both values var phones2: [String: Any] = personal phones2.merge(work) { (personal: $0, work: $1) } ["main": "571-222-9876", "cell": (personal: "202-444-1234", work: "703-987-5678"), "home": "703-333-4567"] Copyright © 2018, About Objects, Inc. 30
Merging Dic*onaries let personal = ["home": "703-333-4567", "cell": "202-444-1234"] let
work = ["main": "571-222-9876", "cell": "703-987-5678"] // If keys match, replaces the current value with the newer value var phones1 = personal phones1.merge(work) { _, new in new } ["main": "571-222-9876", "cell": "703-987-5678", "home": "703-333-4567"] // If keys match, replaces the current value with a tuple of both values var phones2: [String: Any] = personal phones2.merge(work) { (personal: $0, work: $1) } ["main": "571-222-9876", "cell": (personal: "202-444-1234", work: "703-987-5678"), "home": "703-333-4567"] Copyright © 2018, About Objects, Inc. 31
Key-Value Coding 32
Smart KeyPaths (SE-161) • Allows key paths to be used
with non-objc types • New expression syntax for key paths • Similar to property reference, but prefixed with \ for example, \Book.rating • Expression result is an instance of KeyPath Copyright © 2018, About Objects, Inc. 33
Smart KeyPaths Example (1) struct Person { var name: String
var address: Address } struct Address: CustomStringConvertible { var street: String var city: String } let address = Address(street: "21 Elm", city: "Reston") let person = Person(name: "Jo", address: address) let name = person[keyPath: \Person.name] // "Jo" let city = person[keyPath: \Person.address.city] // "Reston" Copyright © 2018, About Objects, Inc. 34
Smart KeyPaths Example (2) • Instances of KeyPath can be
stored let address = Address(street: "21 Elm", city: "Reston") let person = Person(name: "Jo", address: address) // Initialize an array of KeyPaths let keyPaths = [\Person.name, \Person.address.city, \Person.address.street] // Map KeyPaths to an array of property values let values = keyPaths.map { person[keyPath: $0] } // ["Jo", "Reston", "21 Elm"] Copyright © 2018, About Objects, Inc. 35
Smart KeyPaths Example (3) • You can use KeyPaths to
mutate proper3es of non- ObjC types // KeyPaths allow you to mutate properties of Swift types let address = Address(street: "21 Elm", city: "Reston") var mutablePerson = Person(name: "Jo", address: address) mutablePerson[keyPath: \Person.name] = "Kay" mutablePerson[keyPath: \Person.address.city] = "Herndon" // Person(name: "Kay", address: // Address(street: "21 Elm", city: "Herndon")) Copyright © 2018, About Objects, Inc. 36
Codable 37
Swi$ Archival and Serializa1on (SE-166) • Adds protocols for •
Encoders and decoders • Encodable and decodable types • Property keys • User info keys Copyright © 2018, About Objects, Inc. 38
Codable Protocols • Compiler can synthesize default implementa6ons /// A
type that can encode values into a native format /// for external representation. public protocol Encodable { public func encode(to encoder: Encoder) throws } /// A type that can decode itself from an external representation. public protocol Decodable { public init(from decoder: Decoder) throws } public typealias Codable = Decodable & Encodable Copyright © 2018, About Objects, Inc. 39
Standard Library Codable Types • Optional • Array, Dictionary •
String, Int, Double • Date, Data, URL Copyright © 2018, About Objects, Inc. 40
Declaring Codable Types // Declare Person and Dog structs conforming
to Codable struct Person: Codable { var name: String var age: Int var dog: Dog } struct Dog: Codable { var name: String var breed: Breed // Codable has built-in support for enums with raw values. enum Breed: String, Codable { case collie = "Collie" case beagle = "Beagle" case greatDane = "Great Dane" } } Copyright © 2018, About Objects, Inc. 41
Swi$ Encoders (SE-167) • Founda(on framework classes are bridged across
as Swi7 types Swi$ Standard Library Founda1on JSONEncoder NSJSONSerialization JSONDecoder NSJSONSerialization PropertyListEncoder NSPropertyListSerialization PropertyListDecoder NSPropertyListSerialization Copyright © 2018, About Objects, Inc. 42
Encoding to JSON let encoder = JSONEncoder() encoder.outputFormatting = .prettyPrinted
let fred = Person(name: "Fred", age: 30, dog: Dog(name: "Spot", breed: .beagle)) let data = try! encoder.encode(fred) { "name" : "Fred", "age" : 30, "dog" : { "name" : "Spot", "breed" : "Beagle" } } Copyright © 2018, About Objects, Inc. 43
Encoding to JSON let encoder = JSONEncoder() encoder.outputFormatting = .prettyPrinted
let fred = Person(name: "Fred", age: 30, dog: Dog(name: "Spot", breed: .beagle)) let data = try! encoder.encode(fred) { "name" : "Fred", "age" : 30, "dog" : { "name" : "Spot", "breed" : "Beagle" } } Copyright © 2018, About Objects, Inc. 44
Encoding to JSON let encoder = JSONEncoder() encoder.outputFormatting = .prettyPrinted
let fred = Person(name: "Fred", age: 30, dog: Dog(name: "Spot", breed: .beagle)) let data = try! encoder.encode(fred) { "name" : "Fred", "age" : 30, "dog" : { "name" : "Spot", "breed" : "Beagle" } } Copyright © 2018, About Objects, Inc. 45
Decoding from JSON let decoder = JSONDecoder() let fredsClone =
try! decoder.decode(Person.self, from: data) // Person(name: "Fred", // age: 30, // dog: Dog(name: "Spot", // breed: Dog.Breed.beagle)) Copyright © 2018, About Objects, Inc. 46
Decoding from JSON let decoder = JSONDecoder() let fredsClone =
try! decoder.decode(Person.self, from: data) // Person(name: "Fred", // age: 30, // dog: Dog(name: "Spot", // breed: Dog.Breed.beagle)) !" Copyright © 2018, About Objects, Inc. 47
Codable Demo 48
ABOUTOBJECTS 49
Upcoming Classes View online: Public schedule Date Title Mar 12
– 14 Transi-oning to Swi3 Apr 14 – Apr 20 iOS Development in Swi3: Comprehensive Apr 30 – May 4 Advanced iOS Development 50
Q & A 51