SwiftGen is a suite of tools written in Swift to auto-generate Swift code (or anything else actually) for various assets of your project:
enumsfor your Assets Catalogs imagesenumsfor yourLocalizable.stringsstrings.enumsfor your Storyboards and their Scenesenumsfor your Fonts.enumsfor your Colors.
If you're using CocoaPods, you can simply add pod 'SwiftGen' to your Podfile.
This will download the SwiftGen binaries and dependencies in Pods/ during your next pod install execution
and will allow you to invoke it via $PODS_ROOT/SwiftGen/bin/swiftgen in your Script Build Phases.
To install SwiftGen via Homebrew, simply use:
$ brew update
$ brew install swiftgenAlternatively, you can clone the repository and use rake install to build the tool.
With this solution you're sure to build and install the latest version from master.
You can install to the default locations (no parameter) or to custom locations:
# Binary is installed in `./swiftgen/bin`, frameworks in `./swiftgen/lib` and templates in `./swiftgen/templates`
$ rake install
# - OR -
# Binary will be installed in `~/swiftgen/bin`, framworks in `~/swiftgen/fmk` and templates in `~/swiftgen/tpl`
$ rake install[~/swiftgen/bin,~/swiftgen/fmk,~/swiftgen/tpl]The tool is provided as a unique swiftgen binary command-line, with the following subcommands:
swiftgen images [OPTIONS] DIRswiftgen strings [OPTIONS] FILEswiftgen storyboards [OPTIONS] DIRswiftgen colors [OPTIONS] FILEswiftgen fonts [OPTIONS] DIR
Each subcommand has its own option and syntax, but some options are common to all:
--output FILE: set the file where to write the generated code. If omitted, the generated code will be printed onstdout.--template NAME: define the Stencil template to use (by name, see here for more info) to generate the output.--templatePath PATH: define the Stencil template to use, using a full path.
You can use --help on swiftgen or one of its subcommand to see the detailed usage.
You can also see in the wiki some additional doc about how to integrate SwiftGen in your Continuous Integration (Travis-CI, CircleCI, Jenkins, …) and how to integrate in your Xcode project so it rebuild the constants every time you build.
SwiftGen uses Stencil as its template engine.
It comes bundled with some default templates for each of the subcommand (colors, images, strings, storyboard, fonts…), but you can also create your own templates if the defaults don't suit your coding conventions or needs. Simply store them in ~/Library/Application Support/SwiftGen/templates, then use the -t / --template option to specify the name of the template to use.
💡 You can use the swiftgen templates command to list all the available templates (both custom and bundled templates) for each subcommand.
For more information about how to create your own templates, see the dedicated documentation.
Don't hesitate to make PRs to share your improvements suggestions on the default templates 😉
The SwiftGen.playground available in this repository will allow you to play with the code that the tool typically generates, and see some examples of how you can take advantage of it.
This allows you to have a quick look at how typical code generated by SwiftGen looks like, and how you will then use the generated enums in your code.
swiftgen images /dir/to/search/for/imageset/assets
This will generate an enum Asset with one case per image asset in your assets catalog, so that you can use them as constants.
The generated code will look like this:
// The Image type below is typealias'ed to UIImage on iOS and NSImage on OSX
enum Asset: String {
case Green_Apple = "Green-Apple"
case Red_Apple = "Red apple"
case _2_Pears = "2-pears"
var image: Image {
return Image(asset: self)
}
}
extension Image {
convenience init!(asset: Asset) {
self.init(named: asset.rawValue)
}
}let image1 = UIImage(asset: .Banana) // iOS Prefered way
let image2 = NSImage(asset: .Banana) // OS X Prefered way
let image3 = Asset.Apple.image // Alternate wayThis way, no need to enter the "Banana" string in your code and risk any typo.
There are multiple benefits in using this:
- Avoid any typo you could have when using a String
- Free auto-completion
- Avoid the risk to use an non-existing asset name
- All this will be ensured by the compiler.
swiftgen strings /path/to/Localizable.strings
This will generate a Swift enum L10n that will map all your Localizable.strings keys to an enum case. Additionaly, if it detects placeholders like %@,%d,%f, it will add associated values to that case.
Given the following Localizable.strings file:
"alert_title" = "Title of the alert";
"alert_message" = "Some alert body there";
"greetings" = "Hello, my name is %@ and I'm %d";
"apples.count" = "You have %d apples";
"bananas.owner" = "Those %d bananas belong to %@.";The generated code will contain this:
enum L10n {
/// Title of the alert
case AlertTitle
/// Some alert body there
case AlertMessage
/// Hello, my name is %@ and I'm %d
case Greetings(String, Int)
/// You have %d apples
case ApplesCount(Int)
/// Those %d bananas belong to %@.
case BananasOwner(Int, String)
}
extension L10n : CustomStringConvertible {
var description : String { return self.string }
var string : String {
/* Implementation Details */
}
...
}
func tr(key: L10n) -> String {
return key.string
}Reminder: Don't forget to end each line in your *.strings files with a semicolon ;! Now that in Swift code we don't need semi-colons, it's easy to forget it's still required by the Localizable.strings file format 😉
Once the code has been generated by the script, you can use it this way in your Swift code:
let title = L10n.AlertTitle.string
// -> "Title of the Alert"
// Alternative syntax, shorter
let msg = tr(.AlertMessage)
// -> "Some alert body there"
// Strings with parameters
let nbApples = tr(.ApplesCount(5))
// -> "You have 5 apples"
// More parameters of various types!
let ban = tr(.BananasOwner(2, "John"))
// -> "Those 2 bananas belong to John."This script from Lutzifer can be run inside the project to transform NSLocalizedString(...) calls to the tr(...) syntax.
swiftgen storyboards /dir/to/search/for/storyboards
This will generate an enum for each of your UIStoryboard, with one case per storyboard scene.
Note: there is no OS X storyboards yet (but a PR #131 is pending to add that template if you want to help)
The generated code will look like this:
protocol StoryboardSceneType {
static var storyboardName : String { get }
}
extension StoryboardSceneType {
static func storyboard() -> UIStoryboard {
return UIStoryboard(name: self.storyboardName, bundle: nil)
}
static func initialViewController() -> UIViewController {
return storyboard().instantiateInitialViewController()!
}
}
extension StoryboardSceneType where Self: RawRepresentable, Self.RawValue == String {
func viewController() -> UIViewController {
return Self.storyboard().instantiateViewControllerWithIdentifier(self.rawValue)
}
static func viewController(identifier: Self) -> UIViewController {
return identifier.viewController()
}
}
protocol StoryboardSegueType : RawRepresentable { }
extension UIViewController {
func performSegue<S : StoryboardSegueType where S.RawValue == String>(segue: S, sender: AnyObject? = nil) {
performSegueWithIdentifier(segue.rawValue, sender: sender)
}
}
struct StoryboardScene {
enum Message : String, StoryboardSceneType {
static let storyboardName = "Message"
case Composer = "Composer"
static func composerViewController() -> UIViewController {
return Message.Composer.viewController()
}
case URLChooser = "URLChooser"
static func urlChooserViewController() -> XXPickerViewController {
return Message.URLChooser.viewController() as! XXPickerViewController
}
}
enum Wizard : String, StoryboardSceneType {
static let storyboardName = "Wizard"
case CreateAccount = "CreateAccount"
static func createAccountViewController() -> CreateAccViewController {
return Wizard.CreateAccount.viewController() as! CreateAccViewController
}
case ValidatePassword = "Validate_Password"
static func validatePasswordViewController() -> UIViewController {
return Wizard.ValidatePassword.viewController()
}
}
}
struct StoryboardSegue {
enum Message : String, StoryboardSegueType {
case Back = "Back"
case Custom = "Custom"
case NonCustom = "NonCustom"
}
}// Initial VC
let initialVC = StoryboardScene.Wizard.initialViewController()
// Generic ViewController constructor, returns a UIViewController instance
let validateVC = StoryboardScene.Wizard.ValidatePassword.viewController()
// Dedicated type var that returns the right type of VC (CreateAccViewController here)
let createVC = StoryboardScene.Wizard.createAccountViewController()
override func prepareForSegue(_ segue: UIStoryboardSegue, sender sender: AnyObject?) {
switch StoryboardSegue.Message(rawValue: segue.identifier)! {
case .Back:
// Prepare for your custom segue transition
case .Custom:
// Prepare for your custom segue transition
case .NonCustom:
// Prepare for your custom segue transition
}
}
initialVC.performSegue(StoryboardSegue.Message.Back)swiftgen colors /path/to/colors-file.txt
This will generate a enum ColorName with one case per color listed in the text file passed as argument.
The input file is expected to be either:
- a plain text file, with one line per color to register, each line being composed by the Name to give to the color, followed by ":", followed by the Hex representation of the color (like
rrggbborrrggbbaa, optionally prefixed by#or0x). Whitespaces are ignored. - a JSON file, representing a dictionary of names -> values, each value being the hex representation of the color
- a XML file, expected to be the same format as the Android colors.xml files, containing tags
<color name="AColorName">AColorHexRepresentation</color> - a
*.clrfile used by Apple's Color Paletes.
For example you can use this command to generate colors from one of your system color lists:
swiftgen colors ~/Library/Colors/MyColors.clr
Generated code will look the same as if you'd use text file.
Given the following colors.txt file:
Cyan-Color : 0xff66ccff
ArticleTitle : #33fe66
ArticleBody : 339666
ArticleFootnote : ff66ccff
Translucent : ffffffcc
The generated code will look like this:
// The Color type below is typealias'ed to UIColor on iOS and NSColor on OSX
extension Color {
/* Private Implementation details */
...
}
enum ColorName {
/// <span style="display:block;width:3em;height:2em;border:1px solid black;background:#339666"></span>
/// Alpha: 100% <br/> (0x339666ff)
case ArticleBody
/// <span style="display:block;width:3em;height:2em;border:1px solid black;background:#ff66cc"></span>
/// Alpha: 100% <br/> (0xff66ccff)
case ArticleFootnote
/// <span style="display:block;width:3em;height:2em;border:1px solid black;background:#33fe66"></span>
/// Alpha: 100% <br/> (0x33fe66ff)
case ArticleTitle
/// <span style="display:block;width:3em;height:2em;border:1px solid black;background:#ff66cc"></span>
/// Alpha: 100% <br/> (0xff66ccff)
case Cyan_Color
/// <span style="display:block;width:3em;height:2em;border:1px solid black;background:#ffffff"></span>
/// Alpha: 80% <br/> (0xffffffcc)
case Translucent
}
extension Color {
convenience init(named name: ColorName) {
self.init(rgbaValue: name.rgbaValue)
}
}// iOS
UIColor(named: .ArticleBody)
UIColor(named: .ArticleFootnote)
UIColor(named: .ArticleTitle)
UIColor(named: .Cyan_Color)
UIColor(named: .Translucent)
// OS X
NSColor(named: .ArticleBody)
NSColor(named: .ArticleFootnote)
NSColor(named: .ArticleTitle)
NSColor(named: .Cyan_Color)
NSColor(named: .Translucent)This way, no need to enter the color red, green, blue, alpha values each time and create ugly constants in the global namespace for them.
swiftgen fonts /path/to/font/dir
This will recursively go through the specified directory, finding any typeface files (TTF, OTF, …), defining a struct FontFamily for each family, and an enum nested under that family that will represent the font styles.
// The Font type below is typealias'ed to UIFont on iOS and NSFont on OSX
struct FontFamily {
enum Helvetica: String {
case Regular = "Helvetica"
case Bold = "Helvetica-Bold"
case Thin = "Helvetica-Thin"
case Medium = "Helvetica-Medium"
func font(size: CGFloat) -> Font? { return Font(name:self.rawValue, size:size)}
}
}// Helvetica Bold font of point size 16.0
let font = FontFamily.Helvetica.Bold.font(16.0)
// Another way to build the same font
let sameFont = UIFont(font: FontFamily.Helvetica.Bold, size: 16.0) // iOS
let sameFont = NSFont(font: FontFamily.Helvetica.Bold, size: 16.0) // OS XThis code and tool is under the MIT License. See LICENSE file in this repository.
It also relies on Stencil, Commander and PathKit licenses.
Any ideas and contributions welcome!