[rust] Space Age

1 files changed, 37 insertions, 0 deletions

diff --git a/rust/space-age/src/lib.rs b/rust/space-age/src/lib.rs
new file mode 100644
index 0000000..9d24481
--- /dev/null
+++ b/rust/space-age/src/lib.rs
@@ -0,0 +1,37 @@
+#[derive(Debug)]
+pub struct Duration(f64);
+
+impl From<u64> for Duration {
+    fn from(s: u64) -> Self {
+        Self(s as f64)
+    }
+}
+
+pub trait Planet {
+    const EARTH_SECONDS: f64 = 31557600.;
+    const SECONDS_IN_YEAR: f64;
+    fn years_during(d: &Duration) -> f64 { d.0 / Self::SECONDS_IN_YEAR }
+}
+
+
+macro_rules! planets {
+    ( $( $planet:ident -> $ratio:expr ),* ) => {
+        $(
+            pub struct $planet;
+            impl Planet for $planet {
+                const SECONDS_IN_YEAR: f64 = $ratio * Self::EARTH_SECONDS;
+            }
+        )*
+    }
+}
+
+planets!(
+    Mercury -> 0.2408467,
+    Venus -> 0.61519726,
+    Earth -> 1.0,
+    Mars -> 1.8808158,
+    Jupiter -> 11.862615,
+    Saturn -> 29.447498,
+    Uranus -> 84.016846,
+    Neptune -> 164.79132
+);