#![deny(warnings)]
use macro_attr_2018::macro_attr;
macro_rules! EnumIterator {
(() $(pub)* enum $name:ident { $($body:tt)* }) => {
EnumIterator! {
@collect_variants ($name),
($($body)*,) -> ()
}
};
(
@collect_variants ($name:ident),
($(,)*) -> ($($var_names:ident,)*)
) => {
type NameIter = ::std::vec::IntoIter<&'static str>;
type VariantIter = ::std::vec::IntoIter<$name>;
impl $name {
#[allow(dead_code)]
pub fn iter_variants() -> VariantIter {
vec![$($name::$var_names),*].into_iter()
}
#[allow(dead_code)]
pub fn iter_variant_names() -> NameIter {
vec![$(stringify!($var_names)),*].into_iter()
}
}
};
(
@collect_variants $fixed:tt,
($var:ident $(= $_val:expr)*, $($tail:tt)*) -> ($($var_names:tt)*)
) => {
EnumIterator! {
@collect_variants $fixed,
($($tail)*) -> ($($var_names)* $var,)
}
};
}
macro_attr! {
#[derive(Debug, PartialEq, EnumIterator!)]
enum Get { Up, Down, AllAround }
}
#[test]
fn test_enum_iterator() {
let vs: Vec<_> = Get::iter_variant_names().zip(Get::iter_variants()).collect();
assert_eq!(&*vs, &[("Up", Get::Up), ("Down", Get::Down), ("AllAround", Get::AllAround)]);
}