#[macro_export] macro_rules! enum_from_u32 { ($(#[$attr:meta])* pub enum $name:ident { $($(#[$var_attr:meta])* $variant:ident = $e:expr,)* }) => { $(#[$attr])* pub enum $name { $($(#[$var_attr])* $variant = $e),* } impl $name { pub fn from_u32(u: u32) -> Option<$name> { $(if u == $name::$variant as u32 { return Some($name::$variant) })* None } } }; ($(#[$attr:meta])* pub enum $name:ident { $($(#[$var_attr:meta])* $variant:ident,)* }) => { $(#[$attr])* pub enum $name { $($(#[$var_attr])* $variant,)* } impl $name { pub fn from_u32(u: u32) -> Option<$name> { $(if u == $name::$variant as u32 { return Some($name::$variant) })* None } } } }