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