UIKonf talk - CodeGeneration in Swift - Links & Snippets

README-UIKonf17-Talk.md

This is a reference of all the useful links to follow my UIKonf'17 talk on Code Generation in Swift

• Slides on SpeakerDeck
• Keynote Live URL
• All the other files in this GIST contains the code snippets I used in my slides, referenced by slide number.

Slide-08.swift

label.font =
  FontFamily.Avenir.blackOblique.font(size: 18)

label.text =
  L10n.homeGreetings("UIKonf", 1, "Berlin").string

Slide-11.sh

swiftgen fonts "…/Fonts" …

swiftgen strings "…/Localizable.strings" …

swiftgen images "…/Assets.xcassets" …

swiftgen storyboards "$PROJECT_DIR" …

swiftgen colors "…/colors.xml" …

…

Slide-12.swift

enum FontFamily {
  enum Avenir: String {
    case black = "Avenir-Black"
    case blackOblique = "Avenir-BlackOblique"
    case oblique = "Avenir-Oblique"
    case roman = "Avenir-Roman"

    func font(size: CGFloat) -> UIFont! {
      return Font(font: self.rawValue, size: size)
    }
  }
}

Slide-13.swift

enum L10n {
  /// Welcome to %@, the #%d iOS conference in %@!
  case homeGreetings(String, Int, String)

  /// Dismiss changes?
  case editAlertTitle

  /// Changes have been made to the image « %@ »
  case editAlertMessage(String)

  /// Save
  case editAlertSave

  /// Dismiss
  case editAlertDismiss
}

Slide-15.swift

enum Assets {
  static let apple = UIImage(named: "Apple")
  static let banana = UIImage(named: "Banana")
  static let orange = UIImage(named: "Orange")
  static let somePears = UIImage(named: "Some-Pears")
}

// vs

enum Assets: String {
    case apple = "Apple"
    case banana = "Banana"
    case orange = "Orange"
    case somePears = "Some-Pears"

    var image: UIImage {
        return UIImage(named: self.rawValue)
    }
}

Slide-17.stencil

enum Assets {

  {% for image in images %}

    static let {{image|swiftIdentifier}}
      = UIImage(named: "{{image}}")

  {% endfor %}

}

Slide-18.stencil

enum Assets: String {
  {% for image in images %}
    case {{image|swiftIdentifier|lowerFirstWord}} = "{{image}}"
  {% endfor %}

  var image: UIImage {
    return UIImage(asset: self)
  }
}

extension UIImage {
  convenience init!(asset: Assets) {
    self.init(named: asset.rawValue)
  }
}

Slide-21.swift

struct ImageInfo: Equatable {
  let title: String
  let author: String
  let date: Date
}



func == (lhs: ImageInfo, rhs: ImageInfo) -> Bool {
  guard lhs.title == rhs.title else { return false }
  guard lhs.author == rhs.author else { return false }
  guard lhs.date == rhs.date else { return false }
  return true
}

Slide-22.swift

struct ImageInfo: Equatable {
  let title: String
  let author: String
  let date: Date
  let cameraModel: String
  let kind: ImageKind
}

func == (lhs: ImageInfo, rhs: ImageInfo) -> Bool {
  guard lhs.title == rhs.title else { return false }
  guard lhs.author == rhs.author else { return false }
  guard lhs.date == rhs.date else { return false }
  return true
}

Slide-26.stencil

// Template:
There are {{types.all.count}} types in this code, including:
 - {{types.enums.count}} enums
 - {{types.structs.count}} structs
 - {{types.classes.count}} classes
 
// Generated Code:
There are 22 types in this code, including:
 - 11 enums
 - 1 structs
 - 6 classes

Slide-27.swift

struct ImageInfo {
  let title: String
  let author: String
  let date: Date
}

Slide-28.swift

extension ImageInfo: Equatable {}

func == (lhs: ImageInfo, rhs: ImageInfo) -> Bool {
  guard lhs.title == rhs.title
    else { return false }
  guard lhs.author == rhs.author
    else { return false }
  guard lhs.date == rhs.date
    else { return false }

  return true
}

Slide-29.stencil

{% for type in types.implementing.AutoEquatable %}

extension {{ type.name }}: Equatable {}

func == (lhs: {{ type.name }}, rhs: {{ type.name }}) -> Bool {
  {% for variable in type.storedVariables %}
  guard lhs.{{ variable.name }} == rhs.{{ variable.name }}
    else { return false }
  {% endfor %}
  return true
}

{% endfor %}

Slide-30.swift

struct ImageInfo : AutoEquatable {
  let title: String
  let author: String
  let date: Date
}

// + `sourcery/bin/sourcery`

// = Magic

Slide-31.swift

struct Contact {
  let id: String
  let firstName: String
  let lastName: String
}

Slide-32.swift

extension Contact: JSONDeserializable {
  init?(json: [String: Any]) {

    self.id = json["id"] as? String

    self.firstName = json["first_name"] as? String

    self.lastName = json["last_name"] as? String

    self.dateOfBirth = (json["dob"] as? String)
      .flatMap(JSONDateFormatter.date(from:))

    self.avatar = (json["avatar"] as? [String: Any])
      .flatMap(Avatar.init(json:))
  }
}

Slide-33.stencil

{% for type in types.implementing.AutoJSONDeserializable %}

extension {{ type.name }}: JSONDeserializable {
  init?(json: [String: Any]) {
    {% for prop in type.storedVariables %}
    // ?
    {% endfor %}
  }
}

{% endfor %}

Slide-34.sh

// daemon mode to write your templates live:

$ sourcery/bin/sourcery --watch

Slide-35.stencil

// Template (extract)
{% for prop in type.storedVariables %}

    self.{{prop.name}} = json["{{prop.name}}"] as? {{prop.typeName}}

{% endfor %}

// Generated code
self.id = json["id"] as? String
self.firstName = json["firstName"] as? String
self.lastName = json["lastName"] as? String

Slide-36.swift

// Your code
struct Contact {
  let id: String
  // sourcery: JSONKey = "first_name"
  let firstName: String
  // sourcery: JSONKey = "last_name"
  let lastName: String
}

// How to reference that in your template:
{% for prop in type.storedVariables %}
json["{{ prop.annotations.JSONKey |default:prop.name }}"]
{% endfor %}

Slide-37.stencil

// Template
{% for prop in type.storedVariables %}

 self.{{prop.name}} = json["{{ prop.annotations.JSONKey |default:prop.name }}"] as? {{prop.typeName}}

{% endfor %}


// Generated Code
self.id = json["id"] as? String
self.firstName = json["first_name"] as? String
self.lastName = json["last_name"] as? String

Slide-39.swift

struct Customer: AutoEquatable, AutoJSONDeserializable {
  … // 15 properties
}

struct Product: AutoEquatable, AutoJSONDeserializable {
  … // 28 properties
}

struct Cart: AutoEquatable, AutoJSONDeserializable {
  … // 12 properties
}

struct Order: AutoEquatable, AutoJSONDeserializable {
  … // 17 properties
}

enum ShippingOption: AutoCases {
  … // 9 cases
}

Slide-40.swift

// sourcery: TypeErase = PokemonType
protocol Pokemon {
  associatedtype PokemonType
  func attack(move: PokemonType)
}

// + github.com/AliSoftware/SourceryTemplates
// =

let list: [AnyPokemon<Thunder>] = …

SUMMARY-LINKS.md

Other Examples

• Building an API Client using Sourcery Annotations

  • http://littlebitesofcocoa.com/295-building-an-api-client-with-sourcery-key-value-annotations

• Generate JSON Parsing code

  • https://github.com/Liquidsoul/Sourcery-AutoJSONSerializable

• Automatic Type Erasure

  • https://github.com/AliSoftware/SourceryTemplates

Links

• Krzysztof’s talk at CraftConf about Sourcery

  • https://www.ustream.tv/recorded/102903026

• My Live Demo of SwiftGen at NSBudapest

  • Slides: http://speakerdeck.com/alisoftware
  • Video: http://www.ustream.tv/recorded/103135632

• Improve SwiftGen

  • We love contrbutors! ❤️ (Free push access)
  • Lots of very interesting 💡 pending implementation 😉

About me & the tools

• Twitter: @aligatr
• Blog: https://alisoftware.github.io
• My company: Niji
• My GitHub: https://github.com/AliSoftware (OHHTTPStubs, Reusable, …)
• SwiftGen: https://github.com/SwiftGen/SwiftGen
• Sourcery: https://github.com/krzysztofzablocki/Sourcery