Macro event_property 

macro_rules! event_property {
    ($(
        $(#[$meta:meta])+
        $vis:vis fn $on_ident:ident $(< $on_pre_ident:ident $(,)?>)? (
            $child:ident: impl $IntoUiNode:path,
            $handler:ident: $Handler:ty $(,)?
        ) -> $UiNode:path {
            $($body:tt)+
        }
    )+) => { ... };
}

Declare event properties.

Each declaration can expand to an on_event and optionally an on_pre_event. The body can be declared using EventNodeBuilder or VarEventNodeBuilder.

Examples

event_property! {
    /// Docs copied for `on_key_input` and `on_pre_key_input`.
    ///
    /// The macro also generates docs linking between the two properties.
    #[property(EVENT)]
    pub fn on_key_input<on_pre_key_input>(child: impl IntoUiNode, handler: Handler<KeyInputArgs>) -> UiNode {
        // Preview flag, only if the signature contains the `<on_pre...>` part,
        // the macro matches `const $IDENT: bool;` and expands to `const IDENT: bool = true/false;`.
        const PRE: bool;

        // rest of the body can be anything the builds a node.
        EventNodeBuilder::new(KEY_INPUT_EVENT).build::<PRE>(child, handler)
    }

    /// Another property.
    #[property(EVENT)]
    pub fn on_key_down<on_pre_key_down>(child: impl IntoUiNode, handler: Handler<KeyInputArgs>) -> UiNode {
        const PRE: bool;
        EventNodeBuilder::new(KEY_INPUT_EVENT)
            .filter(|| |a| a.state == KeyState::Pressed)
            .build::<PRE>(child, handler)
    }

    /// Another, this time derived from a var source, and without the optional preview property.
    #[property(EVENT)]
    pub fn on_state(child: impl IntoUiNode, handler: Handler<bool>) -> UiNode {
        VarEventNodeBuilder::new(|| CONTEXT.state())
            .map_args(|b| !*b)
            .build::<false>(child, handler)
    }
}

The example above generates five event properties.

Route

Note that is an event property has an on_pre_* pair it is expected to be representing a fully routing event, with args that implement EventArgs. If the property does not have a preview pair it is expected to be a direct event. This is the event property pattern and is explained in the generated documentation, don’t declare a non-standard pair using this macro.

Commands

You can use command_property to declare command event properties, it also generates enabled control properties.