---

yaml
---
r: 52347
b: refs/heads/dist-snap
c: a73f4b1
h: refs/heads/master
i:
  52345: e483990
  52343: df153ef
v: v3

Author: thestinger

[refs]

@@ -7,7 +7,7 @@ refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
 refs/heads/try2: 147ecfdd8221e4a4d4e090486829a06da1e0ca3c
 refs/heads/incoming: 44d4d6de762f3f9aae1fedcf454c66b79b3ad58d
-refs/heads/dist-snap: d44084e10084c1f442f8eb8932590c252eb6df85
+refs/heads/dist-snap: a73f4b1baa3533956582ec9892cc4d1780e45ed0
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503
 refs/heads/try3: 9387340aab40a73e8424c48fd42f0c521a4875c0

branches/dist-snap/src/libstd/treemap.rs

@@ -279,15 +279,45 @@ impl <T: Ord> TreeSet<T> {
 
     /// Visit the values (in-order) representing the symmetric difference
     pure fn symmetric_difference(&self, other: &TreeSet<T>,
-                                 _f: fn(&T) -> bool) {
+                                 f: fn(&T) -> bool) {
         unsafe { // purity workaround
             let mut x = self.map.iter();
             let mut y = other.map.iter();
 
             let mut a = x.next();
             let mut b = y.next();
+
+            while a.is_some() {
+                if b.is_none() {
+                    while a.is_some() {
+                        let (a1, _) = a.unwrap();
+                        if !f(a1) { return }
+                        a = x.next();
+                    }
+                    return
+                }
+
+                let (a1, _) = a.unwrap();
+                let (b1, _) = b.unwrap();
+
+                if a1 < b1 {
+                    if !f(a1) { return }
+                    a = x.next();
+                } else {
+                    if b1 < a1 {
+                        if !f(b1) { return }
+                    } else {
+                        a = x.next();
+                    }
+                    b = y.next();
+                }
+            }
+            while b.is_some() {
+                let (b1, _) = b.unwrap();
+                if !f(b1) { return }
+                b = y.next();
+            }
         }
-        fail ~"not yet implemented"
     }
 
     /// Visit the values (in-order) representing the intersection
@@ -895,6 +925,32 @@ mod test_set {
         assert i == expected.len();
     }
 
+    #[test]
+    fn test_symmetric_difference() {
+        let mut a = TreeSet::new();
+        let mut b = TreeSet::new();
+
+        assert a.insert(1);
+        assert a.insert(3);
+        assert a.insert(5);
+        assert a.insert(9);
+        assert a.insert(11);
+
+        assert b.insert(-2);
+        assert b.insert(3);
+        assert b.insert(9);
+        assert b.insert(14);
+        assert b.insert(22);
+
+        let mut i = 0;
+        let expected = [-2, 1, 5, 11, 14, 22];
+        for a.symmetric_difference(&b) |x| {
+            assert *x == expected[i];
+            i += 1
+        }
+        assert i == expected.len();
+    }
+
     #[test]
     fn test_union() {
         let mut a = TreeSet::new();