Add Angle.

(Also fixed spelling of 'constant').

Author: thejpster

examples/format_test.rs

@@ -1,14 +1,5 @@
 extern crate measurements;
-use measurements::Temperature;
-use measurements::Length;
-use measurements::Pressure;
-use measurements::Volume;
-use measurements::Mass;
-use measurements::Speed;
-use measurements::Acceleration;
-use measurements::Energy;
-use measurements::Power;
-use measurements::Force;
+use measurements::*;
 
 fn main() {
     for power in -12..12 {

src/acceleration.rs

@@ -1,4 +1,4 @@
-//! Types and contants for handling acceleration.
+//! Types and constants for handling acceleration.
 
 use super::measurement::*;
 use super::length;
@@ -16,7 +16,7 @@ use super::length;
 /// let track = Length::from_miles(0.25);
 /// let finish = Speed::from_miles_per_hour(120.0);
 /// let time = Duration::new(10, 0);
-/// let accel = finish / time;
+/// let accel: Acceleration = finish / time;
 /// println!("You accelerated over {} at an average of {}", track, accel);
 /// ```
 #[derive(Copy, Clone, Debug)]

src/angle.rs

@@ -0,0 +1,79 @@
+//! Types and constants for handling angles
+
+use super::measurement::*;
+use ::std::f64::consts::PI;
+
+/// The 'Angle' struct can be used to deal with angles in a common way.
+///
+/// # Example
+///
+/// ```
+/// use measurements::Angle;
+///
+/// let whole_cake = Angle::from_degrees(360.0);
+/// let pieces = 6.0;
+/// let slice = whole_cake / pieces;
+/// println!("Each slice will be {} degrees", slice.as_degrees());
+/// ```
+#[derive(Copy, Clone, Debug)]
+pub struct Angle {
+	radians: f64,
+}
+
+/// Number of degrees in a radian
+pub const RADIAN_DEGREE_FACTOR: f64 = 180.0 / PI;
+
+impl Angle {
+
+	/// Create a new Angle from a floating point value in degrees
+	pub fn from_degrees(degrees: f64) -> Self {
+		Angle::from_radians(degrees / RADIAN_DEGREE_FACTOR)
+	}
+
+	/// Create a new Angle from a floating point value in radians
+	pub fn from_radians(radians: f64) -> Self {
+		Angle { radians: radians }
+	}
+
+	/// Convert this Angle to a floating point value in degrees
+	pub fn as_degrees(&self) -> f64 {
+		self.radians * RADIAN_DEGREE_FACTOR
+	}
+
+	/// Convert this Angle to a floating point value in radians
+	pub fn as_radians(&self) -> f64 {
+		self.radians
+	}
+}
+
+impl Measurement for Angle {
+    fn as_base_units(&self) -> f64 {
+        self.radians
+    }
+
+    fn from_base_units(units: f64) -> Self {
+        Self::from_radians(units)
+    }
+
+    fn as_base_units_name(&self) -> &'static str {
+        "rad"
+    }
+}
+
+implement_measurement! { Angle }
+
+#[cfg(test)]
+mod test {
+	use angle::*;
+	use test_utils::assert_almost_eq;
+
+	#[test]
+	fn radians() {
+		let i1 = Angle::from_degrees(360.0);
+		let r1 = i1.as_radians();
+		let i2 = Angle::from_radians(PI);
+		let r2 = i2.as_degrees();
+		assert_almost_eq(r1, 2.0 * PI);
+		assert_almost_eq(r2, 180.0);
+	}
+}

src/area.rs

@@ -1,4 +1,4 @@
-//! Types and contants for handling areas.
+//! Types and constants for handling areas.
 
 use super::measurement::*;
 use super::length;

src/energy.rs

@@ -1,4 +1,4 @@
-//! Types and contants for handling energy.
+//! Types and constants for handling energy.
 
 use super::measurement::*;
 

src/force.rs

@@ -1,4 +1,4 @@
-//! Types and contants for handling force.
+//! Types and constants for handling force.
 
 use super::measurement::*;
 
@@ -23,7 +23,7 @@ pub const DYNES_PER_NEWTON: f64 = 1e5;
 ///
 /// let metric_ton = Mass::from_metric_tons(1.0);
 /// let gravity = Acceleration::from_meters_per_second_per_second(9.81);
-/// let force = metric_ton * gravity; // F=ma
+/// let force: Force = metric_ton * gravity; // F=ma
 /// println!(
 ///     "One metric ton exerts a force of {} due to gravity",
 ///     force);

src/length.rs

@@ -1,4 +1,4 @@
-//! Types and contants for handling lengths (or distances).
+//! Types and constants for handling lengths (or distances).
 
 use super::measurement::*;
 

src/lib.rs

@@ -45,6 +45,9 @@ pub use force::Force;
 pub mod area;
 pub use area::Area;
 
+pub mod angle;
+pub use angle::Angle;
+
 pub mod prelude;
 
 /// For given types A, B and C, implement, using base units:

src/mass.rs

@@ -1,4 +1,4 @@
-//! Types and contants for handling masses.
+//! Types and constants for handling masses.
 
 use super::measurement::*;
 

src/power.rs

@@ -1,4 +1,4 @@
-//! Types and contants for handling power.
+//! Types and constants for handling power.
 
 use super::measurement::*;