Types in Swift

Cocoa勉強会関西 #60の発表資料です

Transcript

1. ܕ
   <UZQF> @yashigani Cocoaษڧձؔ੢ #60
2. yashigani id:yashigani_w @yashigani Mobile Application Engineer http://yashigani.hatenablog.com Hatena
3. https://flic.kr/p/nBzE6V ܕʹϋϚͬͨ͜ͱ͸͋Γ·͔͢ • ίϯύΠϧΤϥʔʹͳΔ΍ͭͰ͠ΐʁ • ܕ੍ͬͯ໿ͳ͚ͩͰͱʹ͔͘अຐ • id࠷ߴ΍Μʂʂʂܕͱ͔͍ΒΜʂʂʂ
4. ܕͬͯԿʁ
5. ܕ͸ৼΔ෣͍
6. ৼΔ෣͍ • ৼΔ෣͍ = σʔλߏ଄ + ॲཧ • Ͳ͏͍͏σʔλ͕Ͳ͏ಈ࡞͢Δ͔༧૝Ͱ͖Δ • ΠϯλʔϑΣʔε͕ݫ֨
7. $
8. ΞυϨε௕ͷϝλσʔλ • ϝϞϦۭؒʹ͓͚Δม਺ͷҐஔ • ௿ϨΠϠͷॲཧ͕Մೳͳނ • ϓϦϛςΟϒ͗͢Δ
9. 0CKFDUJWF$
10. ৼΔ෣͍ͷϝλσʔλ • isaϙΠϯλ • ม਺͕ৼΔ෣͏΂͖͜ͱΛࣔࠦ(ಈతσΟεύον) • ͨͩ͠ඞͣ͠΋ै͑Δͱ͸ݶΒͳ͍ • ม਺ͷৼΔ෣͍Λଋറ͢Δ΋ͷͰ͸ແ͍
11. 4XJGU
12. ৼΔ෣͍Λ໿ଋ͢Δ΋ͷ • ৼΔ෣͍Λม਺ʹଋറ • ͋Δܕͷม਺͸ͦͷܕͷৼΔ෣͍͔͠͠ͳ͍ • ܕͷ͋Δϓϩάϥϛϯά͕Մೳ
13. ͳͥϓϩάϥϜʹ ܕ͕ඞཁͳͷ͔
14. ܕ ܕ͕͋Δ͔ΒɺܕഁΓɻ
    ܕ͕ͳ͚Ε͹୯ͳΔʮܗແ͠ʯ ʕ
    ेീ୅໨
    தଜצࡾ࿠ Վ෣ب໾ऀ
15. /4%JDUJPOBSZ
16. NSDictionary *user = //... NSString *name = user[@"name"];
17. NSDictionary *user = //... NSString *name; if ([user[@"name"] isKindOfClass: [NSString class]]) { //!!!!! name = user[@"name"]; } else { //!!!!! }
18. https://flic.kr/p/7BD2UE Too bad ߏ଄͕ෆ໌ͳͷͰσʔλͷଘࡏΛஅఆͰ͖ͳ͍ Կ͕ೖ͍ͬͯΔͷ͔ෆ໌ͳͷͰσʔλܕΛࢦఆ ৼΔ෣͍͕ແ͍
19. ܕ͕ແ͍
20. .PEFM
    0CKFDU
    JO
    0CKFDUJWF$
21. @interface User : NSObject @property (copy) NSString *name; @property NSUInteger age; @property (getter=isPremium) BOOL premium; @end
22. User *user = //... UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@" cell"]; cell.textLabel.text = user.name;
23. User *user = //... UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@" cell"]; if (user.name != nil) { cell.textLabel.text = user.name; } else { //!!!!! }
24. https://flic.kr/p/i74K6M Too bad σʔλͷߏ଄ͱܕ͸දݱͰ͖ͨ ΠϯλʔϑΣʔε͕ෆఆ(nilͷՄೳੑ) ৼΔ෣͍͚͕ͩ͋Δ(ଋറ͕ແ͍)
25. ܗແ͠
26. .PEFM
    0CKFDU
    JO
    4XJGU
27. struct User { let name: String let age: Int let isPremium: Bool }
28. let user = //... let cell = tableView.dequeueReusableCellWithId entifier("cell") cell?.titleLabel.text = user.name
29. https://flic.kr/p/egaNwP Relaxed ෆ֬ఆͳཁૉ͸ϏδωεϩδοΫʹӅṭ ΞϓϦέʔγϣϯ͸σʔλΛදࣔ͢Δ͚ͩ ৼΔ෣͍Λଋറ͢Δ͜ͱͰ໿ଋ͞Εͨڍಈ
30. 5IJT
    JT
    ܕ
31. ܕͷ͋ΔϓϩάϥϜ • ৼΔ෣͍͕໌֬Ͱ׬શ • ͕ͨͬͯ͠ෆඞཁͳ৺഑͕͍Βͳ͍ • ϏδωεϩδοΫͱΞϓϦέʔγϣϯͷ෼཭ • ΠϯλʔϑΣʔεͷΈʹґଘ࣮ͨ͠૷
32. 0OF
    NPSF
    UIJOH
33. func parse(JSON: AnyObject?) -> (User?, NSError?) let JSON: AnyObject? = //... let (user, error) = parse(JSON) if let e = error { //... return } if let u = user { //... } else { // maybe user is nil... }
34. https://flic.kr/p/DC3Q Too bad user΋error΋nilͷͱ͖͸Ͳ͏͍͏Τϥʔʁ ΋ͬͱ΋ͬͱstrictʹදݱ͍ͨ͠ (User?, NSError?)͸ૉ๿͗͢Δ
35. ܕΛഁΔ
    ܕʹΑΔܕͷந৅Խ
36. 3FTVMU5
37. enum Result<T> { case Success(T) case Failure(NSError) init(_ value: T) { self = .Success(value) } init(_ error: NSError) { self = .Failure(error) } }
38. ܕഁΓٕ
    ͦͷ
    ʙHFOFSJDTʙ
39. enum Result<T> { case Success(T) case Failure(NSError) init(_ value: T) { self = .Success(value) } init(_ error: NSError) { self = .Failure(error) } } generics
40. ҦΘ͹ϫΠϧυΧʔυܕ • ͱΓ͋͑ͣ͸ͳΜͰ΋ೖΕΒΕΔܕ • ಉ͡ϥϕϧͷ΋ͷ͸ಉ͡ܕ • ΠϯλʔϑΣʔεΛܾΊͨͱ͖ʹܕ͕ܾ·Δ • func parse(_:AnyObject) -> Result<User> • Any/AnyObjectͱҧͬͯղ͘ͱ͖ʹ౎౓ͳʹ͔
 ͔֬ΊΔඞཁ͕ແ͍
41. ܕഁΓٕ
    ͦͷ
    ʙFOVNʙ
42. enum Result<T> { case Success(T) case Failure(NSError) init(_ value: T) { self = .Success(value) } init(_ error: NSError) { self = .Failure(error) } } enum
43. ෳ਺ͷঢ়ଶΛऔΓ͏Δ • Aঢ়ଶͳΒaΛ࣋ͬͯΔ͚ͲɼBঢ়ଶͰ͸࣋ͬͯͳ͍ • ͱΓ͋͑ͣAnyObjectʹͿͪࠐ·ͳ͍͍ͯ͘ • ͲΕ͔ͻͱͭͷঢ়ଶ͔͠औΓಘͳ͍ • A͔ͭBͳঢ়ଶ͸ଘࡏ͠ͳ͍
44. ͭ·ΓResultͱ͸ • ੒ޭ͔ࣦഊ͔ΛऔΓ͏Δ஋ • ੒ޭͨ͠ΒT͕ɼࣦഊͨ͠ΒNSError͕ಘΒΕΔ • ୯७ʹOptional஋Λฒ΂Δͷʹൺ΂ͯѻ͍΍͍͢ • ྆ํ஋͕͋Δ྆ํແ͍ͳΜͯ͜ͱ͸͋Γ͑ͳ͍
45. func parse(JSON: AnyObject?) -> Result<User> let JSON: AnyObject? = // ... let result = parse(JSON) switch result { case .Success(let user): // ... case .Failure(let error): // ... }
46. +VTU
    B
    &JUIFS
47. 0QUJPOBM
48. Optional΋ಉྨ • Optional͸ͻͱͭͷgenericܕΛऔΔenum • enum Optional<T> • ͳʹ͔ͷ஋͕͋Δ/ͳ͍ͷ2छྨͷঢ়ଶΛऔΓ͏Δ • SomeͩͬͨΒTΛ࣋ͬͯΔ • NoneͩͬͨΒnilΛ࣋ͬͯΔ
49. 5IJT
    JT
    ܕഁΓ
50. ·ͱΊ
51. 
    ܕ͸ৼΔ෣͍ͱ஌Δ
    
    ܕͷ͋ΔϓϩάϥϜ
    
    ܕΛഁΔ
52. ͋Γ͕ͱ͏͍͟͝·ͨ͠