Runtime

Contents

How a Program becomes Swift, in parts. Start with the introduction, then follow each part into the rendered output and the runtime it links against.

• Introduction — what the Swift target is, and how to read the rest of this section.
• Capabilities — which high-level features are possible, built in or through a library.
• Example — a full program using every keyword, and the Swift it renders to.
• Naming considerations — how Program's dotted names are carried into Swift.
• Entry point — starting a program and mounting it as a SwiftUI app.
• Drivers — the native drivers that provide the interface, animation and network.
• Runtime — the Reactive and Context machinery the rendered code links against.
• Native modules — the hand-written Swift behind NATIVE functions.
• Keywords — how each of Program's keywords renders to Swift.
• Project setup — the files and commands to build and run the rendered program.
• Reserved words — the words Swift keeps for itself, and how a colliding name is escaped.

Reactive and Context, in Swift

The runtime is the same three parts as every target — the Reactive graph, the Context channels, and the native drivers — ported to Swift. State is Reactive.State<T>(…), a value is a ReactiveValue<T> (a class, for reference identity across cycles), and derived values come from Reactive.Calculate { … }.

Swift's value types map cleanly: a record becomes a struct and a union an enum, both carrying Program's types through real generics. The cycle (open channels, run, drain, dispatch, wait) is identical; read the JavaScript runtime for the full walkthrough.