Add FloatConst implementations

Author: justinlovinger

src/lib.rs

@@ -29,7 +29,7 @@ use num_traits::float::FloatCore as Float;
 #[cfg(feature = "std")]
 pub use num_traits::Float;
 use num_traits::{
-    AsPrimitive, Bounded, FromPrimitive, Num, NumCast, One, Signed, ToPrimitive, Zero,
+    AsPrimitive, Bounded, FloatConst, FromPrimitive, Num, NumCast, One, Signed, ToPrimitive, Zero,
 };
 
 // masks for the parts of the IEEE 754 float
@@ -1537,6 +1537,42 @@ impl<T: Float> NumCast for NotNan<T> {
     }
 }
 
+macro_rules! impl_float_const_method {
+    ($wrapper:expr, $method:ident) => {
+        #[allow(non_snake_case)]
+        fn $method() -> Self {
+            $wrapper(T::$method())
+        }
+    };
+}
+
+macro_rules! impl_float_const {
+    ($type:ident, $wrapper:expr) => {
+        impl<T: FloatConst> FloatConst for $type<T> {
+            impl_float_const_method!($wrapper, E);
+            impl_float_const_method!($wrapper, FRAC_1_PI);
+            impl_float_const_method!($wrapper, FRAC_1_SQRT_2);
+            impl_float_const_method!($wrapper, FRAC_2_PI);
+            impl_float_const_method!($wrapper, FRAC_2_SQRT_PI);
+            impl_float_const_method!($wrapper, FRAC_PI_2);
+            impl_float_const_method!($wrapper, FRAC_PI_3);
+            impl_float_const_method!($wrapper, FRAC_PI_4);
+            impl_float_const_method!($wrapper, FRAC_PI_6);
+            impl_float_const_method!($wrapper, FRAC_PI_8);
+            impl_float_const_method!($wrapper, LN_10);
+            impl_float_const_method!($wrapper, LN_2);
+            impl_float_const_method!($wrapper, LOG10_E);
+            impl_float_const_method!($wrapper, LOG2_E);
+            impl_float_const_method!($wrapper, PI);
+            impl_float_const_method!($wrapper, SQRT_2);
+        }
+    };
+}
+
+impl_float_const!(OrderedFloat, OrderedFloat);
+// Float constants are not NaN.
+impl_float_const!(NotNan, |x| unsafe { NotNan::new_unchecked(x) });
+
 #[cfg(feature = "serde")]
 mod impl_serde {
     extern crate serde;

tests/test.rs

@@ -7,7 +7,7 @@ extern crate ordered_float;
 pub use num_traits::float::FloatCore as Float;
 #[cfg(feature = "std")]
 pub use num_traits::Float;
-pub use num_traits::{Bounded, FromPrimitive, Num, One, Signed, ToPrimitive, Zero};
+pub use num_traits::{Bounded, FloatConst, FromPrimitive, Num, One, Signed, ToPrimitive, Zero};
 pub use ordered_float::*;
 
 pub use std::cmp::Ordering::*;
@@ -693,6 +693,41 @@ fn from_ref() {
     assert_eq!(f, 2.0f64);
 }
 
+macro_rules! test_float_const_method {
+    ($type:ident < $inner:ident >, $method:ident) => {
+        assert_eq!($type::<$inner>::$method().into_inner(), $inner::$method())
+    };
+}
+
+macro_rules! test_float_const_methods {
+    ($type:ident < $inner:ident >) => {
+        test_float_const_method!($type<$inner>, E);
+        test_float_const_method!($type<$inner>, FRAC_1_PI);
+        test_float_const_method!($type<$inner>, FRAC_1_SQRT_2);
+        test_float_const_method!($type<$inner>, FRAC_2_PI);
+        test_float_const_method!($type<$inner>, FRAC_2_SQRT_PI);
+        test_float_const_method!($type<$inner>, FRAC_PI_2);
+        test_float_const_method!($type<$inner>, FRAC_PI_3);
+        test_float_const_method!($type<$inner>, FRAC_PI_4);
+        test_float_const_method!($type<$inner>, FRAC_PI_6);
+        test_float_const_method!($type<$inner>, FRAC_PI_8);
+        test_float_const_method!($type<$inner>, LN_10);
+        test_float_const_method!($type<$inner>, LN_2);
+        test_float_const_method!($type<$inner>, LOG10_E);
+        test_float_const_method!($type<$inner>, LOG2_E);
+        test_float_const_method!($type<$inner>, PI);
+        test_float_const_method!($type<$inner>, SQRT_2);
+    };
+}
+
+#[test]
+fn float_consts_equal_inner() {
+    test_float_const_methods!(OrderedFloat<f64>);
+    test_float_const_methods!(OrderedFloat<f32>);
+    test_float_const_methods!(NotNan<f64>);
+    test_float_const_methods!(NotNan<f32>);
+}
+
 #[cfg(feature = "arbitrary")]
 mod arbitrary_test {
     use super::{NotNan, OrderedFloat};