Widget events 1

The widgets for rat-widget use the trait HandleEvent defined in rat-event.

#![allow(unused)]
fn main() {
    try_flow!(match self.menu.handle(event, Regular) {
        MenuOutcome::Activated(0) => {
            Control::Quit
        }
        v => v.into(),
    });
}

self.menu is the state struct for the menu widget. It can have multiple HandleEvent implementations, typical are Regular and MouseOnly. The second parameter selects the event-handler.

• Regular: Does all the expected event-handling and returns an Outcome value that details what has happened.

• MouseOnly: Only uses mouse events. Generally not very useful except when you want to write your own keybindings for a widget. Then you can forward that part to the MouseOnly handler and be done with the mousey part.

  See mdedit. It overrides only part of the keybindings with its own implementation and forwards the rest to the Regular handler.

• Readonly: Text widgets have a Regular handler and a ReadOnly handler. The latter only moves and allows selections.

• DoubleClick: Some widgets add one. Double clicks are a bit rarer and often require special attention, so this behaviour is split off from Regular handling.

• Dialog and Popup: These are the regular handlers for dialog and popup widgets. They have some irregular behaviour, so it's good to see this immediately.

The handle functions return an outcome value that describes what has happened. This value usually is widget specific.

And there is the try_flow! macro that surrounds it all. It returns early, if the event has been consumed by the handler.