Macro ui 

macro_rules! ui {
    ( $widget:expr => { $( $child:tt )* } ) => { ... };
    ( $widget:expr ) => { ... };
}

Declarative UI macro for building widget trees.

Syntax

ui! {
    Container::new() => {
        Flex::row(12.0) => { btn_a, btn_b },
        label,
    }
}

• widget => { children... } — container with children
• widget — leaf node (no children), automatically wrapped
• Children can be bare widgets or nested container => { ... } expressions
• ui!(widget) still works for explicit leaf wrapping