Mobile Development

Cross-compile Wyn to native arm64 binaries for iOS and Android.

Mobile support today covers the compiled core of an app: develop and test the logic on your desktop, then produce a device-architecture binary with wyn cross. The platform UI shell (which would turn wyn_ui_* calls into real widgets and produce an installable .app/.apk) is not shipped yet, so the wyn_* mobile functions are stubs you declare yourself.

iOS App Shape

// Mobile SDK stubs - declare these yourself for now
fn wyn_ui_text(ctx: int, text: string, size: int) {}
fn wyn_ui_spacer(ctx: int, size: int) {}
fn wyn_ui_button(ctx: int, label: string, id: int) {}
fn wyn_ios_main(a: int, b: int) -> int { return 0 }

fn wyn_app_title() -> string {
    return "My App"
}

fn wyn_app_build(ctx: int) {
    wyn_ui_text(ctx, "Hello World!", 28)
    wyn_ui_spacer(ctx, 16)
    wyn_ui_button(ctx, "Tap Me", 1)
}

fn wyn_on_button(id: int) {
    println("Button tapped!")
}

fn main() -> int {
    return wyn_ios_main(0, 0)
}

Cross-compile for iOS

Requires Xcode's iOS SDK (Command Line Tools alone are not enough):

wyn cross ios app.wyn
# Produces app.wyn.ios (arm64 Mach-O, min iOS 15)

Cross-compile for Android

Requires the Android NDK (Android Studio, SDK Manager, NDK):

wyn cross android app.wyn
# Produces app.wyn.android (arm64)

The output is a bare executable, not an installable app bundle. Shipping to a device still requires an Xcode or Gradle host project that embeds the binary, plus signing. CLI packaging to .app/.apk is on the roadmap.

Planned Shell Contract

The stub names are the planned contract with the future platform shell:

Function	Maps to (planned)	Description
wyn_ui_text(ctx, text, size)	UILabel	Display text
wyn_ui_button(ctx, title, id)	UIButton	Tappable button
wyn_ui_spacer(ctx, height)	UIView	Vertical spacing

On mobile builds the runtime already guards desktop-only behavior: System::exec returns an empty string and Process::exec_status returns -1 instead of shelling out.

Fast Iteration

wyn watch app.wyn

Edit, save, and wyn watch rebuilds and reruns automatically. Develop the app logic on your desktop with stubs, then wyn cross ios/android to produce the device binary.

See Also

• Cross-Compilation - build for other platforms
• Installation - install Wyn