Macro typeenum 

macro_rules! typeenum {
    ( $(#[$attr:meta])* 
        $name:ident,
        $ty:ty,
        {
            $($x:expr => $y:ident),+ $(,)*
        }
        $(,{
            $( $x1:pat => $y1:ident ),* $(,)*
        })?
    ) => { ... };
}

Generate enums for codepoints in protocols.

Example

typeenum!(
    AFI, u16,
    {
        1 => Ipv4,
        2 => Ipv6,
        25 => L2Vpn
    }
);

This will create a pub enum AFI, comprised of variants IPv4, IPv6 and L2Vpn. On this enum, the From (for conversion between the variants and u16) and std::fmt::Display traits are implemented.

You can also specify ranges as like so:

typeenum!(
    PeerType, u8,
    {
        0 => GlobalInstance,
        1 => RdInstance,
        2 => LocalInstance,
        3 => LocalRibInstance,
    },
    {
        4..=250 => Unassigned,
        251..=254 => Experimental,
        255 => Reserved,
    }
);

Note that match lines with ranges are come in a separate block after the block with single selector values. Range variants have a data field with the specified value. Specifying an half-open range to the right or specifying the matches exhaustively will disable the default Unimplemented variant.