Reactive props

Native props accept Value<T>: a literal, Source<T>, derived value, read-only row value or spring. Wrap other getters explicitly; text also has a direct getter overload.

var count = P.Source(0);
var enabled = P.Derive(() => count.Value > 0);
return P.Vertical(
    P.Text(() => $"Count: {count.Value}"),
    P.Button("Reset", onClick: () => count.Value = 0, interactable: enabled)
);

var position = new Value<Vector2>(() => new Vector2(count.Value * 10, 0));
return P.Text("Moving", anchoredPosition: position);

Construct owned calculations inside App.Mount, P.Mount, an owned component renderer or P.Root. Getters track source reads, then update the same native instance. Event callbacks are batched and untracked and retain their declaration context. Disposal removes bindings and handlers. P.Batch groups related writes.

Omitting a nullable prop preserves its native default. For an explicit null reference, pass a typed literal such as new Value<Sprite>((Sprite)null); bare null means omitted. Editable text, value and isOn props write back when supplied a Source<T>. Derived/read-only/getter props are one-way.