Constant BUTTON 

pub const BUTTON: &str = "type Button { label: Str = \"Button\"; action: func() -> Res[Unit, DataError] = noop; }";

A host-rendered control with a typed no-argument action.

The host invokes action through Machine::invoke_component. The default noop is intentional; a Button schema never dispatches an action by itself.

Declaration

type Button { label: Str = "Button"; action: func() -> Res[Unit, DataError] = noop; }

Fields and methods

• label: Visible label; defaults to Button.

• action: Typed zero-argument callback; defaults to noop. Bind a live component method to persist mutations.

Use the default action

The default callback is callable and produces no log output.

let button = Button {};
button.action()?;
print(button.label);

Expose a clickable control

The spawned control retains a typed callback for host click dispatch; initialization makes the example’s ready state observable.

func activate() -> Res[Unit, DataError] { print("activated"); ret Ok(()); }
let control = spawn(Button { label: "Start", action: activate });
print("button ready");