Updates for multiplication and division. Doc and test updates.

Author: James O'Cull

src/length/traits.rs

@@ -19,22 +19,50 @@ impl Sub for Length {
     }
 }
 
-impl Div for Length {
+/// 
+/// Dividing a `Length` by another `Length` returns a ratio.
+/// 
+impl Div<Length> for Length {
+    type Output = f64;
+    
+    fn div(self, rhs: Length) -> f64 {
+        self.meters / rhs.meters
+    }
+}
+
+/// 
+/// Dividing a `Length` by a factor returns a new portion of that length.
+/// 
+impl Div<f64> for Length {
     type Output = Length;
 
-    fn div(self, rhs: Length) -> Length {
-        Length::from_meters(self.meters / rhs.meters)
+    fn div(self, rhs: f64) -> Length {
+        Length::from_meters(self.meters / rhs)
     }
 }
 
-impl Mul for Length {
+/// 
+/// Multiplying a `Length` by another `Length` returns the product of those lengths.
+/// 
+impl Mul<Length> for Length {
     type Output = Length;
 
     fn mul(self, rhs: Length) -> Length {
         Length::from_meters(self.meters * rhs.meters)
     }
 }
 
+/// 
+/// Multiplying a `Length` by a factor increases (or decreases) that length a number of times.
+/// 
+impl Mul<f64> for Length {
+    type Output = Length;
+    
+    fn mul(self, rhs: f64) -> Length {
+        Length::from_meters(self.meters * rhs)
+    }
+}
+
 impl Eq for Length { }
 impl PartialEq for Length {
     fn eq(&self, other: &Length) -> bool {

src/temperature/traits.rs

@@ -19,22 +19,50 @@ impl Sub for Temperature {
     }
 }
 
-impl Div for Temperature {
+/// 
+/// Dividing a Temperature by another Temperature returns a ratio.
+/// 
+impl Div<Temperature> for Temperature {
+    type Output = f64;
+    
+    fn div(self, rhs: Temperature) -> f64 {
+        self.kelvin / rhs.kelvin
+    }
+}
+
+/// 
+/// Dividing a `Temperature` by a factor returns a new portion of that temperature.
+/// 
+impl Div<f64> for Temperature {
     type Output = Temperature;
 
-    fn div(self, rhs: Temperature) -> Temperature {
-        Temperature::from_kelvin(self.kelvin / rhs.kelvin)
+    fn div(self, rhs: f64) -> Temperature {
+        Temperature::from_kelvin(self.kelvin / rhs)
     }
 }
 
-impl Mul for Temperature {
+/// 
+/// Multiplying a `Temperature` by another `Temperature` returns the product of those temperatures.
+/// 
+impl Mul<Temperature> for Temperature {
     type Output = Temperature;
 
     fn mul(self, rhs: Temperature) -> Temperature {
         Temperature::from_kelvin(self.kelvin * rhs.kelvin)
     }
 }
 
+/// 
+/// Multiplying a `Temperature` by a factor increases (or decreases) that temperature a number of times.
+/// 
+impl Mul<f64> for Temperature {
+    type Output = Temperature;
+    
+    fn mul(self, rhs: f64) -> Temperature {
+        Temperature::from_kelvin(self.kelvin * rhs)
+    }
+}
+
 impl Eq for Temperature { }
 impl PartialEq for Temperature {
     fn eq(&self, other: &Temperature) -> bool {

src/tests/length_tests.rs

@@ -169,15 +169,19 @@ fn mul() {
     let a = Length::from_meters(2.0);
     let b = Length::from_meters(4.0);
     let c = a * b;
+    let d = b * 2.0;
     assert_almost_eq(c.as_meters(), 8.0);
+    assert_almost_eq(d.as_meters(), 8.0);
 }
 
 #[test]
 fn div() {
     let a = Length::from_meters(2.0);
     let b = Length::from_meters(4.0);
-    let c = a / b;
-    assert_almost_eq(c.as_meters(), 0.5);
+    let c = a * b;
+    let d = a * 2.0;
+    assert_almost_eq(c.as_meters(), 8.0);
+    assert_almost_eq(d.as_meters(), 4.0);
 }
 
 #[test]

src/tests/temperature_tests.rs

@@ -56,15 +56,19 @@ fn mul() {
     let a = Temperature::from_kelvin(2.0);
     let b = Temperature::from_kelvin(4.0);
     let c = a * b;
+    let d = a * 2.0;
     assert_almost_eq(c.as_kelvin(), 8.0);
+    assert_almost_eq(d.as_kelvin(), 4.0);
 }
 
 #[test]
 fn div() {
     let a = Temperature::from_kelvin(2.0);
     let b = Temperature::from_kelvin(4.0);
     let c = a / b;
-    assert_almost_eq(c.as_kelvin(), 0.5);
+    let d = a / 2.0;
+    assert_almost_eq(c, 0.5);
+    assert_almost_eq(d.as_kelvin(), 1.0);
 }
 
 #[test]