Implement Signed for NotNaN

Author: f-fr

src/lib.rs

@@ -15,7 +15,7 @@ use std::fmt;
 use std::io;
 use std::mem;
 use unreachable::unreachable;
-use num_traits::{Bounded, Float, FromPrimitive, Num, One, ToPrimitive, Zero};
+use num_traits::{Bounded, Float, FromPrimitive, Num, One, Signed, ToPrimitive, Zero};
 
 /// A wrapper around Floats providing an implementation of Ord and Hash.
 ///
@@ -652,6 +652,18 @@ impl<T: Float + Num> Num for NotNaN<T> {
     }
 }
 
+impl<T: Float + Signed> Signed for NotNaN<T> {
+    fn abs(&self) -> Self { NotNaN(self.0.abs()) }
+
+    fn abs_sub(&self, other: &Self) -> Self {
+        NotNaN::new(self.0.abs_sub(other.0)).expect("Subtraction resulted in NaN")
+    }
+
+    fn signum(&self) -> Self { NotNaN(self.0.signum()) }
+    fn is_positive(&self) -> bool { self.0.is_positive() }
+    fn is_negative(&self) -> bool { self.0.is_negative() }
+}
+
 #[cfg(feature = "serde")]
 mod impl_serde {
     extern crate serde;

tests/test.rs

@@ -5,7 +5,7 @@ extern crate ordered_float;
 extern crate num_traits;
 
 pub use ordered_float::*;
-pub use num_traits::{Bounded, Float, FromPrimitive, Num, One, ToPrimitive, Zero};
+pub use num_traits::{Bounded, Float, FromPrimitive, Num, One, Signed, ToPrimitive, Zero};
 pub use std::cmp::Ordering::*;
 pub use std::{f32, f64, panic};
 
@@ -160,6 +160,14 @@ describe! not_nan32 {
         assert_eq!(NotNaN::<f32>::from_str_radix("42.0", 10).unwrap(), NotNaN::from(42.0f32));
         assert!(NotNaN::<f32>::from_str_radix("NaN", 10).is_err());
     }
+
+    it "should implement Signed" {
+        assert_eq!(NotNaN::from(42f32).abs(), NotNaN::from(42f32));
+        assert_eq!(NotNaN::from(-42f32).abs(), NotNaN::from(42f32));
+
+        assert_eq!(NotNaN::from(50f32).abs_sub(&NotNaN::from(8f32)), NotNaN::from(42f32));
+        assert_eq!(NotNaN::from(8f32).abs_sub(&NotNaN::from(50f32)), NotNaN::from(0f32));
+    }
 }
 
 describe! not_nan64 {
@@ -279,6 +287,14 @@ describe! not_nan64 {
         assert_eq!(NotNaN::<f64>::from_str_radix("42.0", 10).unwrap(), NotNaN::from(42.0f64));
         assert!(NotNaN::<f64>::from_str_radix("NaN", 10).is_err());
     }
+
+    it "should implement Signed" {
+        assert_eq!(NotNaN::from(42f64).abs(), NotNaN::from(42f64));
+        assert_eq!(NotNaN::from(-42f64).abs(), NotNaN::from(42f64));
+
+        assert_eq!(NotNaN::from(50f64).abs_sub(&NotNaN::from(8f64)), NotNaN::from(42f64));
+        assert_eq!(NotNaN::from(8f64).abs_sub(&NotNaN::from(50f64)), NotNaN::from(0f64));
+    }
 }
 
 describe! hashing {