From fa83c7a46ab18a152190275e6d5defd96f530bf5 Mon Sep 17 00:00:00 2001
From: Juhana Helovuo <juhana.helovuo@atostek.com>
Date: Tue, 11 Feb 2020 13:35:46 +0200
Subject: [PATCH] Add Curvature.

---
 src/si/curvature.rs | 57 +++++++++++++++++++++++++++++++++++++++++++++
 src/si/mod.rs       |  1 +
 2 files changed, 58 insertions(+)
 create mode 100644 src/si/curvature.rs

diff --git a/src/si/curvature.rs b/src/si/curvature.rs
new file mode 100644
index 00000000..689fc7a6
--- /dev/null
+++ b/src/si/curvature.rs
@@ -0,0 +1,57 @@
+//! [Curvature](https://en.wikipedia.org/wiki/Curvature) (base unit radian per meter, m⁻¹).
+
+quantity! {
+    /// Curvature (base unit radian per meter, m⁻¹).
+    quantity: Curvature; "curvature";
+    /// Dimension of curvature, L⁻¹ (base unit radian per meter, m⁻¹).
+    dimension: ISQ<
+        N1,     // length
+        Z0,     // mass
+        Z0,     // time
+        Z0,     // electric current
+        Z0,     // thermodynamic temperature
+        Z0,     // amount of substance
+        Z0>;    // luminous intensity
+    kind: dyn (::si::marker::AngleKind);
+    units {
+        @radian_per_meter: 1.0_E0; "rad/m", "radian per meter", "radians per meter";
+        @degree_per_meter: 1.745_329_251_994_329_5_E-2; "°/m", "degree per meter",
+            "degrees per meter";
+
+        @radian_per_millimeter: 1000.0; "rad/mm", "radian per millimeter", "radians per millimeter";
+        @degree_per_millimeter: 1.745_329_251_994_329_5_E1; "°/mm", "degree per millimeter",
+            "degrees per millimeter";
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    storage_types! {
+        use num::One;
+        use si::quantities::*;
+        use si::curvature as c;
+        use si::length as l;
+        use si::angle as a;
+        use tests::Test;
+
+        #[test]
+        fn check_dimension() {
+            let _: Curvature<V> =
+                (Angle::new::<a::radian>(V::one())
+                    / Length::new::<l::meter>(V::one())).into();
+        }
+
+        #[test]
+        fn check_units() {
+            test::<a::radian, l::meter, c::radian_per_meter>();
+            test::<a::degree, l::meter, c::degree_per_meter>();
+            test::<a::radian, l::millimeter, c::radian_per_millimeter>();
+            test::<a::degree, l::millimeter, c::degree_per_millimeter>();
+
+            fn test<A: a::Conversion<V>, L: l::Conversion<V>, C: c::Conversion<V>>() {
+                Test::assert_approx_eq(&Curvature::new::<C>(V::one()),
+                    &(Angle::new::<A>(V::one()) / Length::new::<L>(V::one())).into());
+            }
+        }
+    }
+}
diff --git a/src/si/mod.rs b/src/si/mod.rs
index b6918e9e..cdc09b4d 100644
--- a/src/si/mod.rs
+++ b/src/si/mod.rs
@@ -56,6 +56,7 @@ system! {
         capacitance::Capacitance,
         catalytic_activity::CatalyticActivity,
         catalytic_activity_concentration::CatalyticActivityConcentration,
+        curvature::Curvature,
         electric_charge::ElectricCharge,
         electric_current::ElectricCurrent,
         electric_potential::ElectricPotential,