Macro ast_enum_of_structs 

macro_rules! ast_enum_of_structs {
    (
        $(#[$enum_attr:meta])*
        pub enum $name:ident {
            $(
                $(#[$variant_attr:meta])*
                pub $variant:ident $( ($member:ident $($rest:tt)*) )*,
            )*
        }

        $($remaining:tt)*
    ) => { ... };
}