Macro bevy::utils::define_label

macro_rules! define_label {
    (
        $(#[$label_attr:meta])*
        $label_name:ident,

        $(#[$id_attr:meta])*
        $id_name:ident $(,)?
    ) => { ... };
}

Macro to define a new label trait

Example

define_label!(
    /// A class of labels.
    MyNewLabelTrait,
    /// Identifies a value that implements `MyNewLabelTrait`.
    MyNewLabelId,
);