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#![no_std]
pub trait ConstKey<T>: Copy + Clone {
fn value_list() -> &'static [T];
fn get_id(self) -> usize;
fn get(self) -> &'static T {
Self::value_list().get(self.get_id()).unwrap()
}
}
#[macro_export]
macro_rules! const_enum_map {
( $key_type:ident => $item_type:ty , $( $enum_value:ident => $item_value:expr ,)+ ) => {
#[derive(Copy,Clone)]
enum $key_type {
$(
$enum_value ,
)+
}
impl ConstKey<$item_type> for $key_type {
fn value_list()->&'static [$item_type] {
const VALUES:&'static [$item_type] = &[
$( $item_value ),+
];
VALUES
}
fn get_id(self) -> usize {
self as usize
}
}
};
( $key_type:ident => $item_type:ty , $( $enum_value:ident => $item_value:expr ),+ ) => {
const_enum_map! {
$key_type => $item_type ,
$( $enum_value => $item_value ,)+
}
}
}