Macro protocol_constants 

macro_rules! protocol_constants {
    (@construct_u8 $ztype:ty, $val:expr) => { ... };
    (@construct_new $ztype:ty, $val:expr) => { ... };
    (@impl $(#[$outer:meta])*, $type_name:ident, $ztype:ty, $primitive:ty, $strategy:ident, $( $(#[$default:ident])? $const_name:ident = $val:expr; )+ ) => { ... };
    (   $(#[$outer:meta])*
        $type_name:ident,
        u8,
        $primitive:ty:
        $( $(#[$default:ident])? $const_name:ident = $val:expr; )+
    ) => { ... };
    (   $(#[$outer:meta])*
        $type_name:ident,
        $ztype:ty,
        $primitive:ty:
        $( $(#[$default:ident])? $const_name:ident = $val:expr; )+
    ) => { ... };
}