Elm/React.js-like architecture in Swift, powered by ReactiveSwift and LayoutKit.
Zelkova is a genus of six species of deciduous trees in the elm family Ulmaceae (Wikipedia).
Please also check out a sister project: inamiy/SwiftElm (if you like black magic ✨🔮✨)
A simple button tap (increment) example in ZelkovaPlayground.
import UIKit
import PlaygroundSupport
import LayoutKit
import Zelkova
let rootSize = CGSize(width: 320, height: 480)
enum Msg: Message
{
case increment
}
typealias Model = Int
func update(model: Model, msg: Msg) -> Model?
{
switch msg {
case .increment:
return model + 1
}
}
func view(_ model: Model, send: @escaping (Msg) -> ()) -> ButtonLayout<UIButton>
{
return ButtonLayout<UIButton>(
type: .custom,
title: "Tap me! \(model)",
font: .systemFont(ofSize: 24),
contentEdgeInsets: EdgeInsets(top: 10, left: 50, bottom: 10, right: 50),
viewReuseId: "button",
config: {
$0.setTitleColor(.white, for: .normal)
$0.zelkova.addHandler(for: .touchUpInside) { _ in
send(.increment)
}
}
)
}
let program = Program(model: 0, update: update, view: view)
PlaygroundPage.current.liveView = program.rootViewControllerMajority of the code comes from LayoutKit, which works not only as a great layout engine but also as immutable virtual-view framework (just like React.js).
Please see ZelkovaPlayground for more examples.
| Term | Type | Description |
|---|---|---|
| program | Program |
State-machine wrapper that manages whole application's states, view rendering, and event delivery. |
| model | Model |
User-defined application's whole state. |
| msg | Msg |
User-defined input (event message) that triggers Program's state-machine. |
| update | (model: Model, msg: Msg) -> Model? |
State-transition function that takes current state and input as arguments, then returns either a new state (transition success) or nil (transition failure). |
| view | (model: Model, send: @escaping (Msg) -> ()) -> LayoutKit.Layout |
View generating/reusing side-effect that creates LayoutKit.Layout (virtual-view) from current state. To let views to send a new Msg (e.g. button tap), use send to add a new side-effect. |
TBD