Macro item 

macro_rules! item {
    (action: $text:expr, command: $command:expr $(, hotkey: $hotkey:expr)? $(, shortcut: $shortcut:expr)?) => { ... };
    (separator) => { ... };
    (submenu: $text:expr, items: [$($sub_item:expr),*] $(, hotkey: $hotkey:expr)?) => { ... };
}