Formatting for Volume.

Author: thejpster

examples/format_test.rs

@@ -2,14 +2,18 @@ extern crate measurements;
 use measurements::Temperature;
 use measurements::Length;
 use measurements::Pressure;
+use measurements::Volume;
 fn main() {
 	let t = Temperature::from_celsius(123.456);
 	let d = Length::from_meters(123.456);
 	let p = Pressure::from_pascals(123.456);
+	let v = Volume::from_cubic_meters(123.456);
 	println!("Temp of {0:.5} outside", t);
 	println!("Temp of {0:.5} C outside", t.as_celsius());
 	println!("Distance of {0:.5}", d);
 	println!("Distance of {0:.5} m", d.as_meters());
 	println!("Pressure of {0:.5}", p);
 	println!("Pressure of {0:.5} Pa", p.as_pascals());
+	println!("Volume of {0:.5}", v);
+	println!("Volume of {0:.5} m3", v.as_cubic_meters());
 }

src/volume.rs

@@ -211,6 +211,8 @@ implement_measurement! { Volume }
 
 impl ::std::fmt::Display for Volume {
     fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
-        write!(f, "{:.1} m\u{00B3}", self.as_cubic_meters())
+        let p = f.precision().unwrap_or(1);
+        let w = f.width().unwrap_or(0);
+        write!(f, "{volume:width$.prec$}\u{00A0}m\u{00B3}", prec=p, width=w, volume=self.as_cubic_meters())
     }
 }