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
Secret Swift tour
Search
Yuka Ezura
March 01, 2018
Programming
7
2.9k
Secret Swift tour
2018/3/1
try! Swift Conference
Yuka Ezura
March 01, 2018
Tweet
Share
More Decks by Yuka Ezura
See All by Yuka Ezura
Mastering share sheet preview
ezura
4
1.4k
SF Symbols
ezura
9
1.3k
気遣いの iOS プログラミング
ezura
11
3.5k
Swift Album ver.4.1
ezura
3
1.5k
Swift と Kotlin
ezura
4
2.7k
哲学とSwiftの発表
ezura
5
600
アプリが動いたその先へ (iOS アプリ開発編)
ezura
1
1k
Blending Kotlin's culture into Swift
ezura
1
1.3k
Re: エラーと警告でコードをデザインする
ezura
2
980
Other Decks in Programming
See All in Programming
Haskell でアルゴリズムを抽象化する / 関数型言語で競技プログラミング
naoya
17
4.7k
来たるべき 8.0 に備えて React 19 新機能と React Router 固有機能の取捨選択とすり合わせを考える
oukayuka
2
760
既存デザインを変更せずにタップ領域を広げる方法
tahia910
1
230
Rails産でないDBを Railsに引っ越すHACK - Omotesando.rb #110
lnit
1
160
Effect の双対、Coeffect
yukikurage
5
1.4k
Benchmark
sysong
0
200
ReadMoreTextView
fornewid
1
440
KotlinConf 2025 現地で感じたServer-Side Kotlin
n_takehata
1
220
The Evolution of Enterprise Java with Jakarta EE 11 and Beyond
ivargrimstad
1
740
Cloudflare Realtime と Workers でつくるサーバーレス WebRTC
nekoya3
0
410
F#で自在につくる静的ブログサイト - 関数型まつり2025
pizzacat83
0
300
つよそうにふるまい、つよい成果を出すのなら、つよいのかもしれない
irof
1
290
Featured
See All Featured
KATA
mclloyd
29
14k
実際に使うSQLの書き方 徹底解説 / pgcon21j-tutorial
soudai
PRO
181
53k
Keith and Marios Guide to Fast Websites
keithpitt
411
22k
Typedesign – Prime Four
hannesfritz
42
2.7k
Done Done
chrislema
184
16k
Mobile First: as difficult as doing things right
swwweet
223
9.7k
A Modern Web Designer's Workflow
chriscoyier
693
190k
Code Review Best Practice
trishagee
68
18k
I Don’t Have Time: Getting Over the Fear to Launch Your Podcast
jcasabona
32
2.3k
What's in a price? How to price your products and services
michaelherold
245
12k
Documentation Writing (for coders)
carmenintech
71
4.9k
10 Git Anti Patterns You Should be Aware of
lemiorhan
PRO
657
60k
Transcript
Secret Swift tour 2018/3/1 try! Swift Conference Yuka Ezura
var myVariable = 42 myVariable = 50
let r = ( ) Void var myVariable = 42
myVariable = 50
obj?.myVariable = 50
(obj?.myVariable = 50) Optional<Void>
(obj?.myVariable = 50) .map { /* do something */ }
! error: Value of optional type 'Int?' not unwrapped; obj?.myVariable
+ 50
infix operator ⭐ func ⭐ (left: Int, right: Int) ->
Int { return left + right }aaaaaaa
! error: Value of optional type 'Int?' not unwrapped; obj?.myVariable
⭐ 5 infix operator ⭐ func ⭐ (left: Int, right: Int) -> Int { return left + right }aaaaaaa
infix operator ⭐ func ⭐ (left: Int, right: Int) ->
Int { return left + right }aaaaaaa
precedencegroup FoldedIntoOptionalChaining { assignment: true } :FoldedIntoOptionalChaining infix operator ⭐
func ⭐ (left: Int, right: Int) -> Int { return left + right }aaaaaaa
obj?.myVariable ⭐ 5 // => Optional<Int> 1 ⭐ 5 //
=> Int
let myVariable: Int = /* ?? */
let myVariable: Int = { while(true) {} }()
! error: Cannot convert value of type 'Never' to specified
type 'Int' let naver: Never = unsafeBitCast((), to: Never.self) let myVariable: Int = naver
let myVariable: Int = { while(true) {} }()
(source_file (top_level_code_decl (brace_stmt (pattern_binding_decl (pattern_typed type='Int' (pattern_named type='Int' 'myVariable') (type_ident
(component id='Int' bind=Swift.(file).Int))) (call_expr type='Int' location=sample.swift:1:23 range=[sample.swift:1:23 - line:3:3] nothrow arg_labels= (closure_expr type='() -> Int' location=sample.swift:1:23 range=[sample.swift:1:23 - line:3:1] discriminator=0 (parameter_list) (brace_stmt (while_stmt (call_expr implicit type='Int1' location=sample.swift:2:10 range=[sample.swift:2:10 - line:2:15] nothrow arg_labels= (dot_syntax_call_expr implicit type='() -> Int1' location=sample.swift:2:10 range=[sample.swift:2:10 - line:2:15] nothrow (declref_expr implicit type='(Bool) -> () -> Int1' location=sample.swift:2:11 range=[sample.swift: 2:11 - line:2:11] decl=Swift.(file).Bool._getBuiltinLogicValue() function_ref=double) (paren_expr type='(Bool)' location=sample.swift:2:11 range=[sample.swift:2:10 - line:2:15] (call_expr implicit type='Bool' location=sample.swift:2:11 range=[sample.swift:2:11 - line:2:11] nothrow arg_labels=_builtinBooleanLiteral: (constructor_ref_call_expr implicit type='(Int1) -> Bool' location=sample.swift:2:11 range=[sample.swift:2:11 - line:2:11] nothrow (declref_expr implicit type='(Bool.Type) -> (Int1) -> Bool' location=sample.swift:2:11 range=[sample.swift:2:11 - line:2:11] decl=Swift.(file).Bool.init(_builtinBooleanLiteral:) function_ref=single) (type_expr implicit type='Bool.Type' location=sample.swift:2:11 range=[sample.swift:2:11 - line:2:11] typerepr='Bool')) (tuple_expr implicit type='(_builtinBooleanLiteral: Builtin.Int1)' location=sample.swift:2:11 range=[sample.swift:2:11 - line:2:11] names=_builtinBooleanLiteral (boolean_literal_expr type='Builtin.Int1' location=sample.swift:2:11 range=[sample.swift:2:11 - line:2:11] value=true))))) (tuple_expr implicit type='()')) (brace_stmt)))) (tuple_expr type='()' location=sample.swift:3:2 range=[sample.swift:3:2 - line:3:3]))) )) (var_decl "myVariable" type='Int' interface type='Int' access=internal let storage_kind=stored))
(closure_expr type='() -> Int' location=sample.swift:1:23 range=[sample.swift:1:23 - line:3:1] discriminator=0 let
myVariable: Int = { while(true) {} }()
let _: Int = { preconditionFailure() }() let _: Void
= { fatalError() }() let _: Never = { while(true) {} }()
class SomeClass { lazy var v: Int = { preconditionFailure("Variable
'\(#function)' used before being initialized") }()
class SomeClass { var v: Int! lazy var v: Int
= { preconditionFailure("Variable '\(#function)' used before being initialized") }()
Closure
let _: (Int) -> Int = { $0 + 1
}
func f(x: Int...) -> String { … } let _:
(Int...) -> String = f
struct SomeType { func f(x: Int) -> String { …
} } let _: (Int) -> String = SomeType().f let _: (SomeType) -> (Int) -> String = SomeType.f
enum Rank: Int { case ace = 1 case two,
three, four, five, six, seven, eight, nine, ten case jack, queen, king } let _: (Int) -> Rank? = Rank.init init?(rawValue: Int)
let _: (Int, Int) -> (Int) = (+) let _:
(inout Int, Int) -> () = (+=)
enum Page { case settings case externalSite(URL) let _: (URL)
-> Page = Page.externalSite }
static var settings: Page { return Page.settings } static func
externalSite(_ url: URL) -> Page { return Page.externalSite(url) } let _: (URL) -> Page = Page.externalSite enum Page { case settings case externalSite(URL) }
[1.1, 3.2 ,3.5].map(round) [1.1, 3.2 ,3.5].sorted(by: <) ["www.ezura.me", ""].flatMap(URL.init)
inout
let _: (Int...) -> String = f let _: (Int)
-> String = SomeType().f let _: (SomeType) -> (Int) -> String = SomeType.f let _: (Int, Int) -> (Int) = (+) let _: (inout Int, Int) -> () = (+=) let _: (URL) -> Page = Page.externalSite inout
static func +=(lhs: inout Self, rhs: Self) var x =
1 // x: 1 x += 1 // x: 2 inout
! error: Escaping closures can only capture inout parameters explicitly
by value func f(_ arg: inout String) -> () -> () { return { print(arg) } }
func f(_ arg: inout String) { arg = "" arg
= "" } var testString = "" { didSet { print("changed: \(testString)") } } f(&testString) changed:
change to “" change to “" func f(_ arg: inout
String) var testString "" "" "" "" ""
current testString: changed: func f(_ arg: inout String) { arg
= "" sleep(2) arg = "" } var testString = "" { didSet { print("changed: \(testString)") } } DispatchQueue.global().asyncAfter(deadline: .now() + .seconds(1)) { print("current testString: \(testString)") } f(&testString)
func f(_ arg: inout String) { arg = "" sleep(2)
arg = "" } var testString = "" /* { didSet { print("changed: \(testString)") } } */ DispatchQueue.global().asyncAfter(deadline: .now() + .seconds(1)) { print("current testString: \(testString)") } f(&testString) current testString:
change to “" change to “" func f(_ arg: inout
String) var testString "" "" ""
func f(_ arg: inout String) inout change to “" change
to “" var testString "" "" "" "" "" ""
inout return defer
defer execute after all other code in the scope
x++, ++x or neither? /* ??? */ func ++(x: inout
Int) -> Int { defer { x += 1 } return x }
postfix func ++(x: inout Int) -> Int { defer {
x += 1 } return x } x++
func f() { let v: String defer { print(v) }
v = "init value" }
func f() { let v: String defer { print(v) }
v = "init value" }
class SomeType { var v: String { didSet { …
} } init() { defer { v = " in defer" } v = "" v = "" } }
deinit { defer { v = "goodbye in defer" }
changeV() _ = { v = "goodbye in block" }() }
Swift Tour = (obj?.myVariable = 50) .map { /* …
*/ } { while(true) {} }() let _: (inout Int, Int) -> () = (+=) let _: (URL) -> Enum = Enum.case Closure
inout func f(_ arg: inout String) -> () -> ()
{ return { print(arg) } } copy-in copy-out / Optimized inout defer return
defer init() { defer { v = " in defer"
} v = " initialize" } deinit { v = "goodbye " defer { v = "goodbye in defer" } }
Swift Tour myVariable = 50 obj?.myVariable = 50 return Closure
defer didSet inout enum Never init, deinit
Thank you for listening!!