Macro trigger 

macro_rules! trigger {
    (KeyBinding, $key:literal, $location:expr) => { ... };
    (KeyBinding, $key:literal,) => { ... };
    (KeyBinding, $key:ident, $location:expr) => { ... };
    (KeyBinding, $key:ident,) => { ... };
    (MouseBinding, MouseButton::$button:ident,) => { ... };
    (MouseBinding, MouseEvent::$event:ident,) => { ... };
}