Macro menu_items 

macro_rules! menu_items {
    (@process [$($output:expr,)*]) => { ... };
    (@process [$($output:expr,)*] ($i:expr, $m:expr) , $($rest:tt)*) => { ... };
    (@process [$($output:expr,)*] ($i:expr, $m:expr)) => { ... };
    (@process [$($output:expr,)*] ($i:expr) , $($rest:tt)*) => { ... };
    (@process [$($output:expr,)*] ($i:expr)) => { ... };
    (@process [$($output:expr,)*] $item:expr , $($rest:tt)*) => { ... };
    (@process [$($output:expr,)*] $item:expr) => { ... };
    ($($input:tt)*) => { ... };
}

Creates a vec of menu Items

Syntax:

menu_items!(
    (widget),
    (widget, menu),
    expression,
    ...
)