Macro yikes_intenum 

macro_rules! yikes_intenum {
    (
        $( #[$enum_attr:meta] )*
        pub enum $name:ident($ty:ty) {
            $(
              $( #[$variant_attr:meta] )*
              $variant:ident = $value:expr
            ),+ $(,)?
        }
    ) => { ... };
}

A macro that implements useful functionality on integer-based enums.

yikes_intenum::yikes_intenum! {
    /// IP datagram encapsulated protocol.
    pub enum Protocol(u8) {
        HopByHop  = 0x00,
        Icmp      = 0x01,
        Igmp      = 0x02,
        Tcp       = 0x06,
        Udp       = 0x11,
        Ipv6Route = 0x2b,
        Ipv6Frag  = 0x2c,
        IpSecEsp  = 0x32,
        IpSecAh   = 0x33,
        Icmpv6    = 0x3a,
        Ipv6NoNxt = 0x3b,
        Ipv6Opts  = 0x3c
    }
}