A list of cool DSLs made with Swift 5.1’s @functionBuilder
Currently, you instead have to use
@_functionBuilderas it is a private implementation. This will change in the future, however.
Feel free to contribute if you make or find something awesome.
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The proposal has not been fully implemented in the current Xcode betas, which provide a simpler transformation than specified.
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Projects
A list of helpful guides/tutorials on function builders
- Crash course in Swift's 'function builders' with SwiftUI
- Inside SwiftUI's Declarative Syntax's Compiler Magic
- The Swift 5.1 features that power SwiftUI’s API
- Create Your First Function Builder in 10 Minutes
- DependencyInjection - Dependency injection with function builders and property wrappers
DIContainer.register {
New(MediaPlayer() as MediaplayerProtocol)
New { _, id in ArticleViewModel(id: id) as PageViewModelProtocol }
Shared(Router.init, as: RouterProtocol.self, DeeplinkHandler.self)
}- Artemis - Interact with GraphQL in Swift - not strings
Operation(.query) {
Add(\.country, alias: "canada") {
Add(\.name)
Add(\.continent) {
Add(\.name)
}
}.code("CA")
}- graphique - Experimental GraphQL query builders
query("") {
hero {
\.name
lens(\.friends) {
\.name
}
}
}- Graphiti - Swift GraphQL Schema/Type framework for macOS and Linux
Schema<StarWarsAPI, StarWarsStore> {
Enum(Episode.self) {
Value(.newHope)
.description("Released in 1977.")
Value(.empire)
.description("Released in 1980.")
Value(.jedi)
.description("Released in 1983.")
}
.description("One of the films in the Star Wars Trilogy.")
...
}- SociableWeaver - Build declarative GraphQL queries in Swift.
Weave(.query) {
Object(Post.self) {
Field(Post.CodingKeys.title)
Object(Post.CodingKeys.author) {
Field(Author.CodingKeys.id)
Field(Author.CodingKeys.name)
.argument(key: "lastName", value: "Doe")
}
Object(Post.CodingKeys.comments) {
Field(Comment.CodingKeys.id)
Field(Comment.CodingKeys.content)
}
.argument(key: "filter", value: CommentFilter.recent)
}
}- ...
- HTML-DSL - A DSL for writing HTML in Swift
html(lang: "en-US") {
body(customData: ["hello":"world"]) {
article(classes: "readme", "modern") {
h1 {
"Hello World"
}
}
}
}- Vaux - A HTML DSL library for Swift
html {
body {
link(url: url, label: "Google", inline: true)
}
}- ...
- swift-request - Declarative HTTP networking, designed for SwiftUI
Request {
Url("https://jsonplaceholder.typicode.com/todo")
Header.Accept(.json)
}
.onData { ... }let myJson = Json {
JsonProperty(key: "firstName", value: "Carson")
}
myJson["firstName"].string // "Carson"- ...
- NSAttributedStringBuilder - Composing NSAttributedString with SwiftUI-style syntax
NSAttributedString {
AText("Hello world")
.font(.systemFont(ofSize: 24))
.foregroundColor(.red)
LineBreak()
AText("with Swift")
.font(.systemFont(ofSize: 20))
.foregroundColor(.orange)
}- ...
- Corvus – Building RESTful APIs with a declarative syntax.
var api = Api {
BasicAuthGroup<User>("login") { login }
JWTAuthGroup<User.Payload> {
Group("users") { users }
Group("inventory") {
Group("articles") { articles }
}
}
}- ...
- ControlFlowUI - A library that add control flow functionality to SwitUI, using the power of
@functionBuilderandViewBuilder
List(dogs.identified(by: \.name)) { dog in
SwitchValue(dog) {
CaseIs(Animal.self) { value in
Text(value.species)
}
CaseIs(Dog.self) { value in
Text(value.breed)
}
}
}- PathBuilder - Implementation of function builder for SwiftUI Path.
Path {
Move(to: CGPoint(x: 50, y: 50))
Line(to: CGPoint(x: 100, y: 100))
Line(to: CGPoint(x: 0, y: 100))
Close()
}- SwiftWebUI - A demo implementation of SwiftUI for the Web
VStack {
Text("🥑🍞 #\(counter)")
.padding(.all)
.background(.green, cornerRadius: 12)
.foregroundColor(.white)
.tapAction(self.countUp)
}- SequenceBuilder - Allows you to build arbitrary heterogenous sequences without loosing information about the underlying types. It is especially useful for building custom container views in SwiftUI.
struct EnumerationView<Content: Sequence>: View where Content.Element: View {
let content: Content
init(@SequenceBuilder builder: () -> Content) {
self.content = builder()
}
var body: some View {
VStack(alignment: .leading, spacing: 8) {
ForEach(sequence: content) { (index, content) in
HStack(alignment: .top) {
Text("\(index + 1). ")
content
}
}
}
}
}
// Usage:
EnumerationView {
Text("Some text")
VStack {
ForEach(0..<10, id: \.self) { _ in
Text("Lorem ipsum dolet.")
}
}
HStack {
Text("With image:")
Image(systemName: "checkmark")
}
}- Rorschach - Write Xcode UI Tests BDD style 🤷🏻♂️
expect(in: &context) {
Given {
ILearnABitMore()
IBuildARocket()
}
When {
ILaunchARocket()
}
Then {
ICanSeeTheStars()
}
}- BoxLayout - [WIP] SwiftUI's interface like AutoLayout DSL
BoxCenter {
BoxVStack {
BoxElement { toggleView }
BoxEmpty()
.frame(height: 20)
if flag {
BoxElement { top }
.aspectRatio(ratio: CGSize(width: 1, height: 1))
}
}
}Lego {
ForIn(3...4) { x in
Section(layout:FlowLayout(col: x)) {
ForIn(0...(x + 3)) { y in
ImageItem(value: UIImage(named: "\(y % 2)")!)
}
}
}
}- Mockingbird - An experiment of implementing a UI layout and rendering framework inspired by SwiftUI
var content: some Node {
VerticalStack {
Repeated(0..<count) {
Button(action: { self.count += 1 }) {
BoxedText()
}
}
}
.cornerRadius(20)
.animation(.spring)
}- TurtleBuilder - Turtle graphics made on the top of Swift's function builder. It allows you to use a Logo-like syntax to create and draw lines in your Swift project.
let turtle = Turtle {
penDown()
loop(9) {
left(140)
forward(30)
left(-100)
forward(30)
}
penUp()
}- ...
- MenuBuilder - A convenient way to create menus.
let menu = NSMenu {
MenuItem("Click me")
.onSelect { print("clicked!") }
MenuItem("Item with a view")
.view {
MyMenuItemView() // any SwiftUI view
}
SeparatorItem()
MenuItem("About") {
// rendered as disabled items in a submenu
MenuItem("Version 1.2.3")
MenuItem("Copyright 2021")
}
MenuItem("Quit")
.shortcut("q")
.onSelect { NSApp.terminate(nil) }
}
// later, to replace the menu items with different/updated ones:
menu.replaceItems {
MenuItem("New Item").onSelect { print("Hello!") }
}- ...
- Pappe - A Proof of concept embedded interpreted synchronous DSL for Swift.
let m = Module { name in
activity (name.Wait, [name.ticks]) { val in
exec { val.i = val.ticks as Int }
whileRepeat(val.i > 0) {
exec { val.i -= 1 }
await { true }
}
}
activity (name.Main, []) { val in
cobegin {
strong {
doRun(name.Wait, [10])
}
weak {
loop {
doRun(name.Wait, [2])
exec { print("on every third") }
await { true }
}
}
weak {
loop {
doRun(name.Wait, [1])
exec { print("on every second") }
await { true }
}
}
}
exec { print("done") }
}
}- ...
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