devela/num/unit/
helpers.rs

1// devela::num::unit::helpers
2
3// Implements TryFrom for `$to_prim` from the `$unit` type `$from_prim` value
4macro_rules! impl_try_from {
5    ($unit:ty, $from_prim:ty => $($to_prim:ty),+) => {
6        $( impl_try_from![@$unit, $from_prim => $to_prim]; )+
7    };
8
9    (@$unit:ty, $from_prim:ty => $to_prim:ty) => {
10        #[cfg(feature = "cast")]
11        #[cfg_attr(feature = "nightly_doc", doc(cfg(feature = "cast")))]
12        impl TryFrom<$unit> for $to_prim {
13            type Error = $crate::num::NumError;
14            fn try_from(from: $unit) -> Result<$to_prim, Self::Error> { crate::paste! {
15                $crate::num::Cast($from_prim::from(from)).[< checked_cast_to_ $to_prim>]()
16            }}
17        }
18    };
19}
20pub(super) use impl_try_from;