From e4c7d8ec8764d1daf8b247c359d564daea1c113c Mon Sep 17 00:00:00 2001
From: Brendan Zabarauskas <bjzaba@yahoo.com.au>
Date: Thu, 7 Feb 2013 22:54:52 +1100
Subject: [PATCH] Add type parameter for epsilon value

---
 src/libstd/cmp.rs | 47 ++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 42 insertions(+), 5 deletions(-)

diff --git a/src/libstd/cmp.rs b/src/libstd/cmp.rs
index c3c6fc029df..6e783a4be7f 100644
--- a/src/libstd/cmp.rs
+++ b/src/libstd/cmp.rs
@@ -17,12 +17,12 @@ use core::float;
 
 pub const FUZZY_EPSILON: float = 1.0e-6;
 
-pub trait FuzzyEq {
+pub trait FuzzyEq<Eps> {
     pure fn fuzzy_eq(&self, other: &Self) -> bool;
-    pure fn fuzzy_eq_eps(&self, other: &Self, epsilon: &Self) -> bool;
+    pure fn fuzzy_eq_eps(&self, other: &Self, epsilon: &Eps) -> bool;
 }
 
-impl float: FuzzyEq {
+impl float: FuzzyEq<float> {
     pure fn fuzzy_eq(&self, other: &float) -> bool {
         self.fuzzy_eq_eps(other, &FUZZY_EPSILON)
     }
@@ -32,7 +32,7 @@ impl float: FuzzyEq {
     }
 }
 
-impl f32: FuzzyEq {
+impl f32: FuzzyEq<f32> {
     pure fn fuzzy_eq(&self, other: &f32) -> bool {
         self.fuzzy_eq_eps(other, &(FUZZY_EPSILON as f32))
     }
@@ -42,7 +42,7 @@ impl f32: FuzzyEq {
     }
 }
 
-impl f64: FuzzyEq {
+impl f64: FuzzyEq<f64> {
     pure fn fuzzy_eq(&self, other: &f64) -> bool {
         self.fuzzy_eq_eps(other, &(FUZZY_EPSILON as f64))
     }
@@ -64,3 +64,40 @@ fn test_fuzzy_eq_eps() {
     assert (&1.2f).fuzzy_eq_eps(&0.9, &0.5);
     assert !(&1.5f).fuzzy_eq_eps(&0.9, &0.5);
 }
+
+#[test]
+mod test_complex{
+    use cmp::*;
+
+    struct Complex { r: float, i: float }
+
+    impl Complex: FuzzyEq<float> {
+        pure fn fuzzy_eq(&self, other: &Complex) -> bool {
+            self.fuzzy_eq_eps(other, &FUZZY_EPSILON)
+        }
+
+        pure fn fuzzy_eq_eps(&self, other: &Complex,
+                             epsilon: &float) -> bool {
+            self.r.fuzzy_eq_eps(&other.r, epsilon) &&
+            self.i.fuzzy_eq_eps(&other.i, epsilon)
+        }
+    }
+
+    #[test]
+    fn test_fuzzy_equals() {
+        let a = Complex {r: 0.9, i: 0.9};
+        let b = Complex {r: 0.9, i: 0.9};
+
+        assert (a.fuzzy_eq(&b));
+    }
+
+    #[test]
+    fn test_fuzzy_eq_eps() {
+        let other = Complex {r: 0.9, i: 0.9};
+
+        assert (&Complex {r: 0.9, i: 1.2}).fuzzy_eq_eps(&other, &0.5);
+        assert (&Complex {r: 1.2, i: 0.9}).fuzzy_eq_eps(&other, &0.5);
+        assert !(&Complex {r: 0.9, i: 1.5}).fuzzy_eq_eps(&other, &0.5);
+        assert !(&Complex {r: 1.5, i: 0.9}).fuzzy_eq_eps(&other, &0.5);
+    }
+}